[BISC 220] Exam 3

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Open and Closed Circulatory Systems: A circulatory system has:

(1)A circulatory fluid (2) A set of interconnecting vessels (3) A muscular pump, the heart The circulatory system connects the fluid that surrounds cells with the organs that exchange gases, absorb nutrients, and dispose of wastes. Circulatory systems can be open or closed and vary in the number of circuits in the body. In insects, other arthropods, and some molluscs, circulatory fluid called hemolymph bathes the organs directly in an open circulatory system. In a closed circulatory system, blood is confined to vessels and is distinct from the interstitial fluid. Annelids, cephalopods, and vertebrates have closed circulatory systems.

IgG

(monomer). Most abundant Ig class in blood; also present in tissue fluids. Promotes opsoniza- tion, neutralization, and cross-linking of antigens; less effec- tive in activation of complement system than IgM. Only Ig class that crosses placenta, thus conferring passive immunity on fetus

IgE

(monomer). Present in blood at low concen- trations. Triggers release from mast cells and basophils of hista- mine and other chemicals that cause allergic reactions.

artificial passive immunization

, antibodies from an immune animal are injected into a nonimmune animal

Design strategies to deal with diffusion

1) Be small, very small, very very small . In unicellular organisms, exchanges occur directly with the environment 2) Be thin, very thin, very very thin (a) The moon jelly Aurelia, a cnidarian. cnidarians have gastrovascular cavities. The body wall that encloses the cavity is only two cells thick. (b) The planarian Dugesia, a flatworm. Flatworms have a gastrovascular cavity and a flat body that minimizes diffusion distances. 3) Build a circulatory system.

Three Steps of complement proteins

1) Neutralization 2). Opsonization 3). Activation of complement system and pore formation

Explanation of the key functions:

1) filtration by glomerule. 2). Reabsorption of some stuff by blood. 3). Secretion of wastes by blood. 4). Excretion of urine out of the body.

Stent and Balloon

1). A stent and a balloon are inserted into an obstructed artery (obstructed by plaque). 2). Inflating the balloon expands the stent, widening the artery. 3). The balloon is removed, leaving the stent in place, causing increased blood flow.

Evolutionary Adaptations of Pathogens That Underlie Immune System Avoidance

1). Antigenic Variation 2). Latency

Measurement of blood pressure

1). Artery closed by cuff inflated with air (pressure in cuff greater than 120 mmHg) 2). Sounds audible in stethoscope (pressure in cuff drops below 120 mmHg) 3). Sounds stop (Pressure in cuff below 70 mmHg)

Blood Clotting Molecular Foctils

1). Collagen Gibers and Platelet on the wound. Clotting factors from platelets, damaged cells, Plasma (factors like calcium, vitamin K). This causes an enzymatic cascade that catalyzes conversion of Prothrombin to thrombin (thrombin has positive feedback, activating the enzymatic cascade). thrombin catalyzes conversion of fibronogen to fibrin. 2). Platelet Plug 3). Fibrin clot forms

What mechanisms regulate distribution of blood in capillary beds? (2)

1). Constriction or dilation of arterioles that supply capillary beds. 2). Precapillary sphincters that control flow of blood between arterioles and venules Blood flow is regulated by nerve impulses, hormones, and other chemicals

Figure 43.8-3 Major events in a local inflammatory response (3 steps)

1). Histamines and cytokines released. Capillaries dilate. 2). Antimicrobial peptides enter tissue. Neutrophils are recruited. 3). Neutrophils digest pathogens and cell debris. Tissue heals.

The adaptive immune system has four major characteristics:

1). Immense diversity of lymphocytes and receptors. 2). Self-tolerance; lack of reactivity against an animal's own molecules. 3). B and T cells proliferate after activation. 4). Immunological memory

Cycle of Osmolarity

1). Normal Blood Osmolarity (300 mOsm/L). 2). Blood osmolarity increases (such as after sweating profusely). 3). Osmoreceptors in hypothalamus triggers release of ADH (AND GENERATES THIRST). 4). ADH goes to collecting duct; distal tubule. H2O reabsorption. Organism drinks water. 5). Organism returns to normal blood osmolarity.

Regulation of blood volume and blood pressure by the renin-angiotensin-aldosterone system

1). Normal Blood Pressure and Volume. 2). Blood pressure of blood volume drops because of dehydration or blood loss, etc. 3). Sensors in JGA detect decrease. 4). JGA releases Renin. Liver releases Angiotensinogen. 5). Angiotenin I, ACE, Angiotensin II, causes Adrenal gland to releases ALDOSTERONE and arterioles constrict. 6). Back to normal blood pressure and volume.

How Phagocytosis works (6 steps)

1). Pseudopodia surround pathogens. 2). Pathogens engulfed by endocytosis. 3). Vacuole forms. 4). Vacuole and lysosome fuse. 5). Pathogens destroyed. 6). Debris from pathogens released.

Steps of: Figure 43.13a Immunoglobulin (antibody) gene rearrangement (part 1: pre-mRNA)

1). Recombination deletes DNA between randomly selected V segment and J segment 2). Transcription of permanently rearranged, functional gene

Figure 43.13 Immunoglobulin (antibody) gene rearrangement Steps

1). Recombination deletes DNA between randomly selected V segment and J segment. 2). Transcription of permanently rearranged, functional gene. 3). RNA processing. 4). Translation

Steps of Nephron and Collecting Duct (5)

1). proximal tubule. 2). descending limb of loop of Henle. 3). Thin segment of ascending limb -> thick segment. 4). Distal Tubule. 5). Collecting Duct.

Blood Vessel Structure and Function

A vessel's cavity is called the central lumen The epithelial layer that lines blood vessels is called the endothelium The endothelium is smooth and minimizes resistance Capillaries are only slightly wider than a red blood cell

Coordination of ADH and RAAS Activity

ADH and RAAS both increase water reabsorption, but only RAAS will respond to a decrease in blood volume Another hormone, atrial natriuretic peptide (ANP), opposes the RAAS ANP is released in response to an increase in blood volume and pressure and inhibits the release of renin

Balancing ADH and RAAS

ADH and RAAS work in complex feedback circuit to maintain homeostasis. Both increase water re-absorption but counter different osmolarity problems. ADH released in response to increased blood osmolarity in dehydration conditions RAAS responds to changes in blood volume such as wounds that lead to blood loss. Both systems work synergistically

Tardigrade

ANHYDROBIOSIS

AIDS

Acquired immunodeficiency syndrome, or AIDS, is caused by the human immunodeficiency virus (HIV).

Cytokines

Activated macrophages and neutrophils release____, signaling molecules that enhance the immune response. Enhanced blood flow to the site helps deliver antimicrobial peptides that result in an accumulation of pus. Cytokines increase local blood supply and cause the characteristic redness and heat of inflammation. Blood-engorged capillaries leak fluid into neighboring tissue, causing swelling. Enhanced blood flow and vessel permeability aid in delivering clotting elements and antimicrobial proteins to the injured area. Clotting marks the beginning of the repair process and helps block the spread of pathogens elsewhere. Nearby endothelial cells secrete signals that attract neutrophils and macrophages.

Activation of complement system and pore formation

Activation of the complement system by complement proteins. Formation of membrane attack complex. Pore formation allows water and ions to rush inside the foreign cell, which swells and eventually lyses.

Activation of B Cells

Activation of B cells involves helper T cells as well as proteins on the surface of pathogens When an antigen binds a B cell, the cell takes in a few foreign molecules by receptor-mediated endocytosis The class II MHC protein of the B cell then presents an antigen fragment to a helper T cell, a process that is critical to B cell activation. The secretion of antibodies by clonally selected B cells is the hallmark of the humoral immune response. Activation of the humoral immune response typically involves B cells and helper T cells, as well as proteins on the surface of pathogens. B cell activation by an antigen is aided by cytokines secreted from helper T cells that have encountered the same antigen. Stimulated by both an antigen and cytokines, the B cell proliferates and differentiates into memory B cells and antibody-secreting effector cells called plasma cells. The pathway for antigen processing and display in B cells differs from that in other antigen-presenting cells. A macrophage or dendritic cell can present fragments from a wide variety of protein antigens, whereas a B cell presents only the antigen to which it specifically binds. When an antigen first binds to receptors on the surface of a B cell, the cell takes in a few foreign molecules by receptor-mediated endocytosis. The class II MHC protein of the B cell then presents an antigen fragment to a helper T cell. This direct cell-to-cell contact is usually critical to B cell activation.

1). Proximal Tubule

Active Transport IN: H+. Passive Transport IN: NH3. Active Transport OUT: NaCl, Nutrients. Passive Transport OUT: HCO3-, H2O, K+.

4). Distal Tubule.

Active Transport IN: K+, H+. Passive Transport IN: none. Active Transport OUT: NaCl, HCO3-. Passive Transport OUT: H2O.

5). Collecting Duct

Active Transport IN: none. Passive Transport IN: none. Active Transport OUT: NaCl Passive Transport OUT: Urea, H2O.

3). Thick segment of ascending limb.

Active Transport IN: none. Passive Transport IN: none. Active Transport OUT: NaCl. Passive Transport OUT: none.

2). Descending limb of loop of Henle

Active Transport IN: none. Passive Transport IN: none. Active Transport OUT: none. Passive Transport OUT: H2O.

3). Thin segment of ascending limb.

Active Transport IN: none. Passive Transport IN: none. Active Transport OUT: none. Passive Transport OUT: NaCl.

Land Animals

Adaptations to reduce water loss are key to survival on land Body coverings of most terrestrial animals help prevent dehydration Desert animals get major water savings from simple anatomical features and behaviors such as a nocturnal lifestyle Land animals maintain water balance by eating moist food and producing water metabolically through cellular respiration

How do Leukocytes move?

Adhesion and Rolling

Figure 43.13b Immunoglobulin (antibody) gene rearrangement (part 2: polypeptide)

After both the light- and heavy-chain genes have rearranged, antigen receptors can be synthesized. The rearranged genes are transcribed, and the transcripts are processed for translation. Following translation, the light chain and heavy chain assemble together, forming an antigen receptor. Each pair of randomly rearranged heavy and light chains results in a different antigen-binding surface. For the total population of B cells in a human body, the number of such combinations has been calculated as 3.5 x 106. Furthermore, mutations introduced during VJ recombination and from Somatic Hypermutation add additional variation, making the number of possible antigen-binding specificities even greater.

Double Circulation

Amphibians, reptiles, and mammals have _____. Oxygen-poor and oxygen-rich blood are pumped separately from the right and left sides of the heart. In reptiles and mammals, oxygen-poor blood flows through the pulmonary circuit to pick up oxygen through the lungs In amphibians, oxygen-poor blood flows through a pulmocutaneous circuit to pick up oxygen through the lungs and skin Oxygen-rich blood delivers oxygen through the systemic circuit Double circulation maintains higher blood pressure in the organs than does single circulation

Forms of Nitrogenous Waste

Animals excrete nitrogenous wastes in different forms: ammonia, urea, or uric acid These differ in toxicity and the energy costs of producing them

Transport Epithelia in Osmoregulation

Animals regulate the solute content of body fluid that bathes their cells. ___ are epithelial cells specialized for moving solutes in specific directions They are typically arranged into complex tubular networks An example is in nasal glands of marine birds, which remove excess sodium chloride from the blood

Antibodies

Antibodies do not kill pathogens, but by binding to antigens they mark pathogens in various ways for inactivation or destruction. In neutralization, antibodies bind to viral surface proteins and prevent infection of a host cell, thus neutralizing the virus. Similarly, antibodies sometimes bind to toxins released in body fluids, preventing the toxins from entering body cells.

Origin of Self-Tolerance

Antigen receptors are generated by random rearrangement of DNA. As lymphocytes mature in bone marrow or the thymus, they are tested for self-reactivity. Some B and T cells with receptors specific for the body's own molecules are destroyed by apoptosis, or programmed cell death. The remainder are rendered nonfunctional. Because antigen receptor genes are randomly rearranged, some immature lymphocytes produce receptors specific for epitopes on the organism's own molecules. If these self-reactive lymphocytes were not eliminated or inactivated, the immune system could not distinguish self from nonself and would attack body proteins, cells, and tissues. Instead, as lymphocytes mature in the bone marrow or thymus, their antigen receptors are tested for self-reactivity. Some B and T cells with receptors specific for the body's own molecules are destroyed by apoptosis or programmed cell death. The remaining self-reactive lymphocytes are typically rendered nonfunctional, leaving only those that react to foreign molecules. Since the body normally lacks mature lymphocytes that can react against its own components, the immune system is said to exhibit self-tolerance.

Figure 43.12 Antigen recognition by T cells

Antigen recognition involving T cells begins when a pathogen or part of a pathogen either infects or is taken in by a host cell. Inside the host cell, enzymes in the cell cleave the antigen into smaller peptides. Each peptide, called an antigen fragment, then binds to an MHC molecule inside the cell. If the cell displaying an antigen fragment encounters a T cell with the right specificity, the antigen receptor on the T cell can bind to both the antigen fragment and the MHC molecule. The interaction of an MHC molecule, an antigen fragment, and an antigen receptor allows a T cell to participate in an adaptive immune response.

Which cells have class I and class II MHC molecules on their surfaces

Antigen-presenting cells

Blood travel through pipes -> list order AREA in cm^2

Aorta (around 0) Arteries (around 0-1000) Arterioles (rises from 1000 to around 4000) Capillaries (peaks, 4000 to 4500 to 4000) Venules (Drops from around 4000 to 1500) Veins (around 1500-0) Venae Cavae (around 0)

Blood travel through pipes -> list order VELOCITY in (cm/sec)

Aorta (around 50) Arteries (drops from around 48 to around 30) Arterioles (Drops from around 30 to around 0) Capillaries (0) Venules (rises from around 0 to 10) Veins (rises from around 10 to around 22) Venae Cavae (rises to 25)

Blood travel through pipes -> list order PRESSURE (in mmHg)

Aorta (peaks that rise linearly and have a jagged drop, between 75 and 115 about) Arteries (jagged peaks start to taper from 75 and 115 to 70 and 90) Arterioles (peaks drop from 65 and 80 to 40 and 45) Capillaries (smooth exponential descent from 40 to 20) Venules (smooth exponential descent from 20 to 10) Veins (smooth drop from 10 to 0) Venae Cavae (drops down to 0)

Blood travel through pipes -> list order

Aorta -> Arteries -> arterioles -> capillaries -> venules -> veins -> Venae cavae

Arteries, Veins, and the Heart

Arteries and veins are distinguished by the direction of blood flow, not by O2 content. Vertebrate hearts contain two or more chambers. Blood enters through an atrium and is pumped out through a ventricle

Artery Structure

Arteries have thicker walls than veins to accommodate the high pressure of blood pumped from the heart In the thinner-walled veins, blood flows back to the heart mainly as a result of muscle action

b cells

B cells attach to the helper t cells that have been activated by the antigen presenting cell. The activated t cell talks with cytokines with the B cells, which proliferates into either memory b cells or plasma cells (that secrete antibodies).

Immunoglobulin

B cells can express five different forms of immunoglobulin (Ig). For a given B cell, each form or class has an identical antigen-binding specificity, but a distinct heavy chain C region. The B cell antigen receptor, known as IgD, is membrane bound. The other four classes consist of soluble antibodies. IgM is the first class of soluble antibody produced. IgG, which follows next, is the most abundant antibody in blood. The remaining antibody classes are IgA and IgE). IgD is membrane bound, while the other four, IgA, IgE, IgG, and IgM are soluble

Capillary Function

Blood flows through only 5-10% of the body's capillaries at any given time Capillaries in major organs are usually filled to capacity Blood supply varies in many other sites. At any given time, only about 5-10% of the body's capillaries have blood flowing through them. Capillaries in the brain, heart, kidneys, and liver are usually filled to capacity, but in many other sites, the blood supply varies over times as blood is diverted. For example, after a meal, blood supply to the digestive tract increases. During strenuous exercise, blood is diverted from the digestive tract and supplied to skeletal muscles.

Blood Composition and Function

Blood in vertebrates is a connective tissue consisting of several kinds of cells suspended in a liquid matrix called plasma The cellular elements occupy about 45% of the volume of blood

Blood Pressure and Gravity

Blood pressure is generally measured for an artery in the arm at the same height as the heart Blood pressure for a healthy 20-year-old human at rest is about 120 mm Hg at systole and 70 mm Hg at diastole Gravity has a significant effect on blood pressure

Afferent Arteriole

Blood vessel entering the renal corpuscle

Renal Artery

Blood vessel that carries blood to the kidney

Generation of B and T Cell Diversity (2)

By combining variable elements, the immune system assembles a diverse variety of antigen receptors. The immunoglobulin (Ig) gene encodes one chain of the B cell receptor . Many different chains can be produced from the same gene by rearrangement of the DNA. Rearranged DNA is transcribed and translated and the antigen receptor formed. Each person makes more than 1 million different B cell antigen receptors and more than 10 million different T cell antigen receptors. Yet there are only roughly 20,000 protein-coding genes in the human genome. By combining variable elements, the immune system assembles many different receptors from a much smaller collection of parts. The capacity to generate diversity is built into the structure of Ig genes.

One Way Valves and Pressure; Blood Flow in Veins

By the time blood reaches the veins, its pressure is not affected much by the action of the heart. The resistance of tiny arterioles and capillaries has dissipated the pressure generated by the pumping heart. Rhythmic contractions of smooth muscles in the walls of veins and venules account for some movement of blood. More importantly, the activity of skeletal muscles during exercise squeezes blood through the veins. One-way valves built into veins ensure that blood flows toward the heart. In addition, inhalation changes the pressure in the thoracic (chest) cavity, causing the venae cavae and other large veins near the heart to expand and fill with blood.

Capillaries Structure

Capillaries have thin walls, the endothelium plus its basal lamina, to facilitate the exchange of materials Arteries and veins have an endothelium, smooth muscle, and connective tissue Capillaries have a diameter only slightly greater than that of a red blood cell. The very thin walls of capillaries consist of just endothelium and its basal lamina, thus enhancing exchange.

Collecting Duct

Carries filtrate from medulla of kidney to renal pelvis. Site where concentration of urine is influenced by hormones targeting permeability and transport and influence concentrations. Aquaporin channels allow water to cross epithelium. Epithelium in renal cortex is impermeable to NaCl and urea Filtrate becomes more concentrated as it loses water by osmosis due to hyper-osmolarity of interstitial fluid. At inner medulla, collecting duct is permeable to urea, and this urea and NaCl maintain hyper-osmolarity of interstitial fluid. Result: urine is hyperosmotic to body fluids.

Natural Killer Cells

Cellular innate defenses in vertebrates also involve ____. These circulate through the body and detect abnormal cells. They release chemicals leading to cell death, inhibiting the spread of virally infected or cancerous cells. Many cellular innate defenses involve the lymphatic system._____ do not engulf stricken cells. Instead, they release chemicals that lead to cell death, inhibiting further spread of the virus or cancer.

Transplantation Factors

Chances of successful transplantation increase if donor and recipient MHC tissue types are well matched Immunosuppressive drugs facilitate transplantation Lymphocytes in bone marrow transplants may cause the donor tissue to reject the recipient

Blood Clotting

Coagulation is the formation of a solid clot from liquid blood A cascade of complex reactions converts inactive fibrinogen to fibrin, forming a clot A blood clot formed within a blood vessel is called a thrombus and can block blood flow

Figure 43.9 The structure of a B cell antigen receptor

Each B cell receptor for an antigen is a Y-shaped molecule consisting of four polypeptide chains: two identical heavy chains and two identical light chains linked by disulfide bridges. A transmembrane region near one end of each heavy chain anchors the receptor in the cell's plasma membrane. A short region at the end of the tail extends into the cytoplasm. At the two tips of the Y-shaped molecules are the light- and heavy-chain variable (V) regions whose amino acid sequences vary from one B cell to another. The remainder of the molecule is made up of constant (C) regions, which do not vary from cell to cell. Each B cell receptor has two identical antigen-binding sites formed from parts of a heavy-chain V region and parts of a light-chain V region.

Antigen Recognition by T Cells

Each T cell receptor consists of two different polypeptide chains (called alpha and beta). The tips of the chain form a variable (V) region; the rest is a constant (C) region. T cell and B cell antigen receptors are functionally different

The interrelationship of cross-sectional area of blood vessels, blood flow velocity, and blood pressure

Each artery conveys blood to such an enormous number of capillaries that the total cross-sectional area is much greater in capillary beds than in any other part of the circulatory system. Blood flows at speeds of about 0.1 cm/sec in the capillaries and 48 cm/sec in the aorta.

Kidney Anatomy: Organs

Each kidney is supplied with blood by a renal artery and drained by a renal vein. In humans, the kidneys account for less than 1% of body weight, but they receive about 25% of the blood exiting the heart. Urine exits each kidney through a duct called the ureter, and both ureters drain into a common urinary bladder. During urination, urine is expelled from the urinary bladder through a tube called the urethra, which empties to the outside near the vagina in females or through the penis in males. Sphincter muscles near the junction of the urethra and the bladder control urination.

Nephrons

Each nephron consists of a single long tubule and a ball of capillaries, called the glomerulus. The blind end of the tubule forms a cup-shaped swelling, called Bowman's capsule, that surrounds the glomerulus. Each human kidney contains about a million nephrons, with a total tubule length of 80 km.

Metanephridia

Each segment of an earthworm has a pair of open-ended metanephridia Metanephridia consist of tubules that collect coelomic fluid and produce dilute urine for excretion Metanephridia of earthworms function in excretion and osmoregulation. Metanephridia, a tubular excretory system found in most annelids, consist of internal openings that collect body fluids from the coelom through a ciliated funnel. Beating of the cilia draws fluid into a coiled collecting tubule, which includes a storage bladder that opens to the outside. An earthworm's metanephridia have both excretory and osmoregulatory functions. As urine moves along the tubule, the transport epithelium bordering the lumen reabsorbs most solutes and returns them to the blood in the capillaries. Nitrogenous wastes remain in the tubule and are dumped outside. Because earthworms experience a net uptake of water from damp soil, their metanephridia balance water influx by producing dilute urine.

countercurrent multiplier system

Energy is expended to actively transport NaCl from the filtrate in the upper part of the ascending limb The ______ involving the loop of Henle maintains a high salt concentration in the kidney This system allows the vasa recta to supply the kidney with nutrients, without interfering with the osmolarity gradient

Artery Structure Descrip

Enothelium, thin, on the insie. Smooth muscle, thick, around the endothelium. Connective tissue surrounds the endothelium. a bit more than 100 micrometers in diameter.

Name the different TLRs and what they recognize.

Figure 43.6 TLR signaling "Das ist ja toll!" TLR3 on the inner surface of endocytic vesicles is the sensor for double-stranded RNA, a form of nucleic acid characteristic of certain viruses. TLR4 of immune cell plasma membranes recognizes lipopolysaccharide, a molecule found on the surface of many bacteria. TRL5 recognizes flagellin, a protein that composes bacterial flagella. TRL9 recognizes Unmethylated CpG dinucleotide sites. CpG sites are relatively rare (~1%) on vertebrate genomes in comparison to bacterial genomes or viral DNA

Basal Lamina

First layer of basement membrane. Secreted by the overlying epithelial tissue. In epithelial tissues with more than one layer, the basal layer refers to the deepest layer of epithelial cells.

Freshwater Animals

Freshwater animals constantly take in water by osmosis from their hypoosmotic environment They lose salts by diffusion and maintain water balance by drinking almost no water and excreting large amounts of dilute urine Salts lost by diffusion are replaced in foods and by uptake across the gills

Explanation of Filtrate's Path

From Bowman's capsule, the filtrate passes through three regions of the nephron: the proximal tubule; the loop of Henle, a hairpin turn with a descending limb and an ascending limb; and the distal tubule. The distal tubule empties into a collecting duct, which receives processed filtrate from many nephrons. The many collecting ducts empty into the renal pelvis, which is drained by the ureter. In the human kidney, about 85% of the nephrons, the cortical nephrons, have reduced loops of Henle and are almost entirely confined to the renal cortex. The other 15%, the juxtamedullary nephrons, have well-developed loops that extend deeply into the renal medulla. It is the juxtamedullary nephrons that enable mammals to produce urine that is hyperosmotic to body fluids, conserving water. The nephron and the collecting duct are lined by a transport epithelium that processes the filtrate to form the urine. Their most important task is to reabsorb solutes and water. The nephrons and collecting ducts reabsorb nearly all of the sugar, vitamins, and other organic nutrients from the initial filtrate and about 99% of the water. This reabsorption reduces 180 L of initial filtrate to about 1.5 L of urine to be voided. Each nephron is supplied with blood by an afferent arteriole, a branch of the renal artery that subdivides into the capillaries of the glomerulus. The capillaries converge as they leave the glomerulus, forming an efferent arteriole. This vessel subdivides again into the peritubular capillaries, which surround the proximal and distal tubules. Additional capillaries extend downward to form the vasa recta, a loop of capillaries that serves the loop of Henle. The tubules and capillaries are immersed in interstitial fluid, through which substances diffuse. Although the excretory tubules and their surrounding capillaries are closely associated, they do not exchange materials directly. The tubules and capillaries are immersed in interstitial fluid, through which various materials diffuse between the plasma in the capillaries and the filtrate within the nephron tubule. The vasa recta and the loop of Henle function together as part of a countercurrent system that enhances nephron efficiency.

Nephron Organization

helper t cells

Helper T Cell is round. It is attached to the antigen-presenting (flowery) cell by both a CLASS II MHC MOLECULE and an ACCESSORY PROTEIN. The mhc molecule is attached to the helper t cell by the antigen receptor. The antigen-presenting cell has engulfed the pathogen and cut it into fragments, which it displays on the class II mhc molecule for the antigen receptor to bind to. The two cells communicate by cytokines. After this, the helper t cells CLONE, and then communicate with either B-cells (humoral immunity, or secretion of antibodies) or CYTOTOXIC T-CELLS (for cell-mdiated immunity, which attacks infected cells).

Attack on the Immune System: HIV

Human immunodeficiency virus (HIV) infects helper T cells HIV persists in the host—despite an immune response—because it has a high mutation rate that promotes antigen variation Over time an untreated HIV infection not only avoids the adaptive immune response, but abolishes it

Organization of Vertebrate Circulatory Systems

Humans and other vertebrates have a closed circulatory system called the cardiovascular system. The three main types of blood vessels are arteries, veins, and capillaries Blood flow is one way in these vessels

Figure 43.5 Inquiry: Can a single antimicrobial peptide protect fruit flies against infection?

Immune cells of insects bind to molecules found only in the outer layers of bacteria or fungi. Fungal cell walls have unique polysaccharides, while bacterial cell walls contain combinations of sugars and amino acids not found in animal cells. For example, when the fungus Neurospora crassa infects a fruit fly, pieces of the fungal cell wall bind a recognition protein. Together, the complex activates the protein Toll, a receptor on the surface of hemocytes. Signal transduction from the Toll receptor to the cell nucleus leads to synthesis of a particular set of antimicrobial peptides active against fungi. When the bacterium Micrococcus luteus infects a fly, a distinct recognition protein is activated, and the fly produces a different set of antimicrobial peptides. Because fruit flies secrete many distinct antimicrobial peptides in response to a single infection, it is difficult to study the activity of any one peptide. Bruno Lemaitre and fellow researchers in France used modern genetic techniques to reprogram the fly immune system. They found that the synthesis of a single type of antimicrobial peptide in the fly's body could provide an effective immune defense. Furthermore, particular antimicrobial peptides act against pathogens from different subgroups. The Graph: % survival (y) vs hours post-infextion (x). Fruit fly survival after infextion by N. crassa fungi: Mutant + drosomycin lived; mutant + defensin died. Infection by M luteus bacteria: mutant + drosomycin died; mutant + defensin lived.

Immunological Memory

Immunological memory is responsible for long-term protections against diseases. The first exposure to a specific antigen represents the primary immune response . During this time, selected B and T cells give rise to their effector forms. In the secondary immune response, memory cells facilitate a faster, more efficient response. Immunological memory provides long-term protection from a prior infection or vaccination. Prior exposure to an antigen alters the speed, strength, and duration of the immune response. The production of effector cells from a clone of lymphocytes during the first exposure to an antigen is the basis for the primary immune response, which peaks 10 to 17 days after the initial exposure. During this time, selected B cells and T cells give rise to their effector forms. If an individual is exposed again to the same antigen, the response is faster (peaking 2 to 7 days after exposure), of greater magnitude, and more prolonged. This is the secondary immune response. Because selected B cells give rise to antibody-secreting effector cells, measuring the concentrations of specific antibodies in blood over time distinguishes the primary and secondary immune response. The secondary immune response relies on the reservoir of T and B memory cells generated following initial exposure to an antigen. Because these cells are long-lived, they provide the basis for immunological memory, which can span many decades. Effector cells have much shorter life spans, which is why the immune response diminishes after an infection is overcome. If an antigen is encountered again, memory cells specific for that antigen enable the rapid formation of clones of thousands of effector cells specific for this antigen, thus generating a greatly enhanced immune defense.

Structure of Blood Vessels in Detail

Impulses from the nervous system and hormones circulating in the blood act on smooth muscle in arteries, controlling blood flow to different parts of the body. The thinner-walled veins convey blood back to the heart at low velocity and pressure. Blood flows through the veins mainly because skeletal muscle contractions squeeze blood in veins. Within larger veins, flaps of tissues act as one-way valves that allow blood to flow only toward the heart.

Malpighian Tubules

In insects and other terrestrial arthropods, Malpighian tubules remove nitrogenous wastes from hemolymph and function in osmoregulation Insects produce a relatively dry waste matter, mainly uric acid, an important adaptation to terrestrial life Some terrestrial insects can also take up water from the air. Insects and other terrestrial arthropods have organs called Malpighian tubules that remove nitrogenous wastes and also function in osmoregulation. The tubules open into the digestive system and dead-end at tips that are immersed in the hemolymph. The filtration step common to other excretory systems is absent. The transport epithelium lining the tubules secretes certain solutes, including nitrogenous wastes, from the hemolymph into the lumen of the tubule. Water follows the solutes into the tubule by osmosis, and the fluid then passes into the rectum, where most of the solutes are pumped back into the hemolymph. Water again follows the solutes, and the nitrogenous wastes, primarily insoluble uric acid, are eliminated along with the feces. This system is highly effective in conserving water and is one of several key adaptations contributing to the tremendous success of insects on land.

Innate Immunity of Invertebrates

In insects, an exoskeleton made of chitin forms the first barrier to pathogens. The digestive system is protected by a chitin-based barrier and lysozyme. Hemocytes circulate within hemolymph and carry out phagocytosis. Invertebrates have highly effective innate defenses. Insect exoskeletons are a first line of defense against infection. Composed largely of the polysaccharide chitin, the exoskeleton provides an effective barrier defense against most pathogens. A chitin-based barrier is also present in the insect intestine, where it blocks infection by many pathogens ingested with food. Lysozyme, an enzyme that digests bacterial cell walls, also protects the digestive system. In insects, circulating cells called hemocytes travel through the hemolymph, the insect circulatory fluid.

The Two-Solute Model - How the human kidney concentrates urine

In the glomerulus, osmolarity is 300 mOsm/L. In the proximal tubule, it is still 300. As it descends the limb of loop of henle, it rises from 300 - 400 - 600 - 900, until it reaches 1200 mOsm/L at the bottom. During this whole process down the loop of Henle, water goes out passively. As the filtrate turns the bend, the osmolarity drops from 1200 to 700 to 400 for the thin ascending limb (where NaCl passively diffuses out AND UREA [from collecting duct] PASSIVELY DIFFUSES IN). for the thick ascending limb, the osmolarity goes from 400 to 200 to 100 and NaCl is pumped out actively. In the distal tubule, the osmolarity remains at 100. Once it goes into the collecting duct though, it rises once more from 300 to 400 to 600 to 900 to finally 1200. H2O diffuses out passively, as does urea. NaCl is pumped ut actively as well, but only in the outer medulla (the 400 to 600 osmolarity range).

Concentrating Urine in the Mammalian Kidney

In the proximal tubule, filtrate volume decreases as water and salt are reabsorbed, but osmolarity remains the same As the filtrate flows to the descending limb of the loop of Henle, solutes become more concentrated due to water leaving the tubule by osmosis NaCl diffusing from the ascending limb maintains a high osmolarity in the interstitial fluid of the renal medulla In the collecting duct, osmosis extracts water from the filtrate as it passes from cortex to medulla and encounters interstitial fluid of increasing osmolarity Urine produced is isoosmotic to the interstitial fluid of the inner medulla, but hyperosmotic to blood and interstitial fluids elsewhere in the body

Immunodeficiency Diseases

Inborn immunodeficiency results from a genetic or developmental defect in the innate or adaptive defenses, or both Acquired immunodeficiency develops later in life due to exposure to chemical and biological agents. Diminished immune responses can cause disease. In immunodeficiency diseases, the immune system response to pathogens is defective or absent. An immunodeficiency disease caused by a genetic or developmental defect in the immune system is called an inborn immunodeficiency. An immunodeficiency defect in the immune system that develops later in life, following exposure to a chemical or biological agent, is called an acquired immunodeficiency. Inborn immunodeficiencies result from defects in the development of various immune system cells or the production of specific proteins, such as antibodies or the proteins of the complement system. In severe combined immunodeficiency (SCID), functional lymphocytes are rare or absent. Individuals with this disease require a bone marrow or stem cell transplant in order to supply functional lymphocytes. Immune deficiencies may also develop later in life. Drugs used to fight autoimmune diseases or prevent transplant rejection suppress the immune system, leading to an immunodeficient state. Certain cancers suppress the immune system. An example is Hodgkin's disease, which damages the lymphatic system. Acquired immunodeficiency syndrome, or AIDS, is caused by the human immunodeficiency virus (HIV).

Tissue and Organ Transplants

MHC molecules are different among genetically nonidentical individuals. Differences in MHC molecules stimulate rejection of tissue grafts and organ transplants. In the case of tissue and organ transplants, or grafts, MHC molecules stimulate the immune response that leads to rejection. Each vertebrate species has many different alleles for each MHC gene, enabling presentation of antigen fragments that vary in shape and charge. This diversity of MHC molecules guarantees that no two people, except identical twins, will have exactly the same set. In the vast majority of graft and transplant recipients, some MHC molecules on the donated tissue are foreign to the recipient. To minimize rejection, physicians try to use donor tissue bearing MHC molecules that match those of the recipient as closely as possible. The recipient takes medicines that suppress immune responses; this leaves the recipient more susceptible to infections during the course of treatment. Bone marrow transplants are used to treat leukemia and other cancers as well as various hematological (blood cell) diseases. The recipient is typically treated with radiation to eliminate his or her own bone marrow cells, destroying the source of abnormal cells. This treatment obliterates the recipient's immune system, eliminating graft rejection. However, lymphocytes in the donated marrow may react against the recipient. This graft versus host reaction is limited if the MHC molecules of the donor and recipient are well matched. Bone marrow donor programs continually seek volunteers because the great variability of MHC molecules makes a diverse pool of donors essential

4-chambered hearts

Mammals and birds have a four-chambered heart with two atria and two ventricles The left side of the heart pumps and receives only oxygen-rich blood, while the right side receives and pumps only oxygen-poor blood Mammals and birds are endotherms and require more O2 than ectotherms

Concept 44.5: Hormonal circuits link kidney function, water balance, and blood pressure

Mammals can control the volume and osmolarity of urine in response to changes in salt intake and water availability

Mast Cells, IgE, and the allergic response

Mast Cell is exposed initially to allergens; by second exposure the igE's come and cross-linking triggers release of histamine. The next time the allergen enters the body, it binds to mast cell-associated IgE molecules Mast cells release histamine and other mediators that cause vascular changes leading to typical allergy symptoms An acute allergic response can lead to anaphylactic shock, a life-threatening reaction, within seconds of allergen exposure

Perforin

One of the proteins released by cytotoxic T cells on contact with their target cells. It forms pores in the target cell membrane that contribute to cell killing.

Atrial Natriuretic Peptide (ANP)

Opposes RAAS ANP released by walls of atria of heart in response to increase in blood volume and pressure ANP inhibits the release of renin from JGA, inhibits NaCl reabsorption by collecting ducts, and reduces the release of aldosterone from adrenal glands. Results in lowered blood pressure and volume

Plasma

Plasma contains inorganic salts as dissolved ions, sometimes called electrolytes Plasma proteins influence blood pH and help maintain osmotic balance between blood and interstitial fluid Particular plasma proteins function in lipid transport, immunity, and blood clotting Plasma is similar in composition to interstitial fluid, but plasma has a much higher protein concentration

Drosophilia GFP experiment

Poking it with bacteria caused the GFP to light up. Figure 43.4 An inducible innate immune response. Transgenic fruit-fly, with GFP under control of a genetic promoter that is sensitive to anti-microbial peptides. Tissue-specific inducible expression of antimicrobial peptide genes in Drosophila surface epithelia: "In order to study the expression pattern of the various antimicrobial peptides in Drosophila, we established transgenic strains expressing the green fluorescent protein (GFP) under the control of the promoters of the corresponding genesThe reporter genes ( Figure 1) were injected into embryos, and several independent insertions were obtained and characterized for each transposon. The transgenic larvae and flies were pricked with a bacteria-soaked needle and examined under epifluorescent illumination with a dissecting scope, 6-48 hr later."

Opsonization (step)

Promotion of phagocytosis of bacteria by macrophages and neutrophils

Proximal Tubule

Reabsorption of ions, water, and nutrients takes place in the proximal tubule Molecules are transported actively and passively from the filtrate into the interstitial fluid and then capillaries As the filtrate passes through the proximal tubule, materials to be excreted become concentrated Some toxic materials are actively secreted into the filtrate

Descending Limb of Loop of Henle

Reabsorption of water (loss of water from filtrate) Water channels formed by aquaporin make the transport epithelium permeable to water Lack of channels for other solutes (low permeability) Osmosis of water due to hyper-osmolarity of interstitial fluid surrounding descending loop of Henle Filtrate increases solute concentration as descends

Innate Immunity of Vertebrates

Recognition of traits shared by broad ranges of pathogens, using a small set of receptors. rapid response. Barrier defenses: skin, mucous membranes, secretions. Internal Defenses: Phagocytic cells, natural killer cells, antimicrobial proteins, inflammatory response. The immune system of mammals is the best understood of the vertebrates. Innate defenses include barrier defenses, phagocytosis, antimicrobial peptides. Additional defenses unique to vertebrates are natural killer cells, interferons, and the inflammatory response

Adaptive Immunity of Vertebrates

Recognition of traits specific to particular pathogens, using a vast array of receptors. Slower response. Humoral Response: Antibodies defend against infection in body liquids. Cell-mediated response: cytotoxic cells defend against infection in body cells.

Distal Tubule

Regulates K+ and NaCl concentration in fluids. Involves re-absorbtion of NaCl from filtrate and secretion of K+ into filtrate. Regulation of pH by secretion of H+ and re-absorption of HCO3- (bicarbonate)

NO and endothelin

Researchers have identified a gas, nitric oxide (NO), as a major inducer of vasodilation and a peptide, endothelin, as the most potent inducer of vasoconstriction. Both NO and endothelin are produced in blood vessels in response to cues from the nervous and endocrine systems. Each molecule binds to a specific receptor, activating a signal transduction pathway that alters smooth muscle contraction and thus changes blood vessel diameter.

SA node part 1

Signals from SA node spread through atria. On ECG, there is a small round bump.

Disruptions in immune system function can elicit or exacerbate disease

Some pathogens have evolved to diminish the effectiveness of host immune responses If the delicate balance of the immune system is disrupted, effects can be severe. Exaggerated immune responses can cause disease. Allergies are hypersensitive (exaggerated) responses to certain environmental antigens, called allergens. The most common allergies involve antibodies of the IgE class. Hay fever, for example, occurs when plasma cells secrete IgE specific for pollen allergens. Some IgE antibodies attach by their base to mast cells present in connective tissue. Later, pollen grains that enter the body attach to the antigen-binding sites of mast-cell-associated IgE, cross-linking adjacent antibody molecules. This event triggers the mast cell to release histamines and other inflammatory chemicals from vesicles called granules. These inflammatory events lead to typical allergy symptoms: sneezing, runny nose, teary eyes, and smooth muscle contractions that can result in breathing difficulty. Antihistamines diminish allergy symptoms by blocking receptors for histamine. Sometimes, an acute allergic response can result in anaphylactic shock, a whole-body, life-threatening reaction to injected or ingested allergens. Anaphylactic shock results when widespread release of mast cell contents triggers abrupt dilation of peripheral blood vessels, causing a precipitous drop in blood pressure and constriction of branchioles. Death may occur within minutes due to lack of blood flow and inability to breathe. Triggers of anaphylactic shock in susceptible individuals include bee venom, penicillin, or foods such as peanuts or fish. Some hypersensitive individuals carry syringes with epinephrine, which counteracts this allergic response.

Differentiation of blood cells FROM stem cells

Stem Cells (in bone marrow) become either Lymphoid Stem Cells or Myeloid Stem Cells. Lymphoid Stem Cells become lymphocytes (B cells or T cells) Myeloid Stem Cells become Erythrocytes, Neutrophils, Basophils, Monocytes, Platelets, Eosinophils

Cellular Elements

Suspended in blood plasma are two types of cells Red blood cells (erythrocytes) transport O2 White blood cells (leukocytes) function in defense Platelets are fragments of cells that are involved in clotting

HEart PRessure of a Human versus other animals

The arterial blood pressure of a healthy human oscillates between about 120 mm Hg at systole and 70 mm Hg at diastole. In large land animals, blood pressure is also affected by gravity. When a person stands up, an extra 27 mm of Hg pressure is required to move blood from the heart to the brain. If blood flow to the brain is inadequate, fainting may result. Fainting places the head at the level of the heart, thus reducing the need for additional blood pressure. A giraffe requires a systolic pressure near the heart of over 250 mm Hg. One-way valves and sinuses, as well as feedback mechanisms that reduce cardiac output, prevent this high pressure from damaging the giraffe's brain when it puts its head down. Long-necked dinosaurs would have required even higher systolic pressure—nearly 760 mm Hg—to pump blood to their brains when their heads were fully raised. Such blood pressures seem unlikely; it is more likely that these dinosaurs fed close to the ground rather than raising their heads to feed on high foliage.

Four valves prevent backflow of blood in the heart

The atrioventricular (AV) valves separate each atrium and ventricle The semilunar valves control blood flow to the aorta and the pulmonary artery

Phagocytic cell types

There are two main types of phagocytic cells in the mammalian body. Neutrophils. Macrophages . There are two additional types of phagocytic cells. Dendritic cells. Eosinophils.

Coupling Vasoconstriction and Vasodilation

Vasoconstriction and vasodilation may be coupled to changes in cardiac output that affect blood pressure. This coordination of regulatory mechanisms maintains adequate blood flow as the demands on the circulatory system change. For example, during strenuous exercise, arterioles in the working muscles dilate, admitting a greater flow of oxygen-rich blood to the muscles and decreasing peripheral resistance. At the same time, cardiac output increases, maintaining blood pressure and supporting the necessary increase in blood flow.

Step 3 of Cardiac Cycle

Ventricular systole and atrial diastole, 0.3 sec. Blood is pushed out of ventricles; blood rushes into atria.

Osmosis and Osmolarity

Water enters and leaves cells by osmosis Osmolarity, the solute concentration of a solution, determines the movement of water across a selectively permeable membrane If two solutions are isoosmotic, water molecules will cross the membrane at equal rates in both directions. If two solutions differ in osmolarity, the net flow of water is from the hypoosmotic (less concentrated) to the hyperosmotic (more concentrated) solution

MHC (major histocompatibility complex) molecules

While the antigen receptors of B cells bind to epitopes of intact antigens circulating in body fluids, those of T cells bind only to fragments of antigens that are displayed, or presented, on the surface of host cells. The host protein that displays the antigen fragment on the cell surface is called an ______. T cells bind to antigen fragments displayed or presented on a host cell. These antigen fragments are bound to cell-surface proteins called _______. _____ molecules are host proteins that display the antigen fragments on the cell surface. In infected cells, ____s bind and transport antigen fragments to the cell surface, a process called antigen presentation. A T cell can then bind both the antigen fragment and the MHC molecule. This interaction is necessary for the T cell to participate in the adaptive immune response

pus

a fluid rich in white blood cells, dead pathogens, and cell debris from damaged tissues

Septic shock

a life-threatening condition caused by an overwhelming inflammatory response

Protonephridia (s. um)

a network of dead-end tubules connected to external openings The smallest branches of the network are capped by a cellular unit called a flame bulb These tubules excrete a dilute fluid and function in osmoregulation. Protonephridia are found in rotifers, some annelids, larval molluscs, and lancelets. In freshwater flatworms, the major function of the flame-bulb system is osmoregulation, whereas most metabolic wastes diffuse across the body surface or are excreted into the gastrovascular cavity. In some parasitic flatworms, however, protonephridia do dispose of nitrogenous wastes.

Fever

a systemic inflammatory response triggered by substances released by macrophages in response to certain pathogens

Mast cells

a type of connective tissue. releases histamine

Pathogens

agents that cause disease, infect a wide range of animals, including humans. An animal body offers a ready source of nutrients, a protected setting for growth, and a means of transport to new environments. Immune cells interact with and destroy ____. Responses to infection include proteins that punch holes in bacterial membranes or block viruses from entering body cells.

Hypertension

aka high blood pressure, also contributes to heart attack and stroke, as well as other health problems _____ can be controlled by dietary changes, exercise, and/or medication

heart attack

aka myocardial infarction, is the damage or death of cardiac muscle tissue resulting from blockage of one or more coronary arteries

Class I MHC proteins

all cells with nuclei

Erythrocytes

are the most numerous blood cells They contain hemoglobin, the iron-containing protein that transports O2 Each molecule of hemoglobin binds up to four molecules of O2 In mammals, mature erythrocytes lack nuclei and mitochondria

Monoclonal Antibodies

are used in many types of medical diagnoses and treatments Human chorionic gonadotropin in pregnancy tests

Dendreon

autologous cancer vaccine. uses PSA/GM-CSF fed to DCs. extends life expectancy by 4 months

Renal Vein

blood vessel that carries blood away from the kidney and toward the heart

Arteries

branch into arterioles and carry blood away from the heart to capillaries Networks of capillaries called capillary beds are the sites of chemical exchange between the blood and interstitial fluid

thrombus

can block blood flow. A blood clot formed within a blood vessel

Euryhaline animals

can survive large fluctuations in external osmolarity

Class II MHC proteins

dendritic cells, macrophages, B-cells. Class II MHC molecules are the basis upon which antigen-presenting cells are recognized Antigen receptors on the surface of helper T cells bind to the antigen and the class II MHC molecule; then signals are exchanged between the two cells The helper T cell is activated, proliferates, and forms a clone of helper T cells, which then activate the appropriate B cells. The antigen receptors on the surface of the helper T cell bind to the antigen fragment and to the class II MHC molecule displaying that fragment on the antigen-presenting cell. At the same time, an accessory protein on the helper T cell surface binds to the class II MHC molecule, helping keep the cells joined. As the two cells interact, signals in the form of cytokines are exchanged in both directions. For example, cytokines secreted from a dendritic cell act in combination with the antigen to stimulate the helper T cell, causing it to produce its own set of cytokines. Extensive contact between the cell surfaces enables further information exchange. The different types of antigen-presenting cells interact with helper T cells in distinct contexts. Antigen presentation by a dendritic cell or macrophage activates a helper T cell. The helper T cell then proliferates, forming a clone of activated helper T cells. B cells present antigens to already activated helper T cells, which in turn activate the B cells themselves. Activated helper T cells also help stimulate cytotoxic T cells, as we'll discuss next.

IgA

has a j-chain and a secretory component. (dimer). Present in secretions such as tears, saliva, mucus, and breast milk. Provides localized defense of mucous membranes by cross-linking and neutralization of antigens. Presence in breast milk confers passive immunity on nursing infant. After birth, a nursing mother continues to transfer protection against disease to her infant. IgA antibodies present in breast milk provide additional passive immunity to the infant's digestive tract while the infant's immune system develops. Later in life, IgA functions in active immunity: IgA antibodies secreted in tears, saliva, and mucus protect the mucous membranes of both males and females.

IgM

has a j-chain. (pentamer). First Ig class produced after initial exposure to antigen; then its concentration in the blood declines. Promotes neutraliza- tion and cross- linking of antigens; very effective in complement system activation

IgD

has a transmembrane region. (monomer)Present primarily on surface of B cells that have not been exposed to antigens. Acts as antigen receptor in the antigen-stimulated proliferation and differentiation of B cells (clonal selection)

Immune systems

help animals to avoid or limit many infections.

Aldosterone

hormone which increases blood volume and pressure

The Renin-Angiotensin-Aldosterone System (RAAS)

is part of a complex feedback circuit that functions in homeostasis A drop in blood pressure near the glomerulus causes the juxtaglomerular apparatus (JGA) to release the enzyme renin Renin triggers the formation of the peptide angiotensin II

Diastolic pressure

is the pressure in the arteries during diastole; it is lower than systolic pressure

Systolic pressure

is the pressure in the arteries during ventricular systole; it is the highest pressure in the arteries. Arteriole blood pressure is highest when the heart contracts during ventricular systole, producing systolic pressure.

pulse

is the rhythmic bulging of artery walls with each heartbeat. When you take your pulse by placing your fingers on your wrist, you can feel an artery bulge with each heartbeat. The surge of pressure is partly due to the narrow openings of arterioles impeding the exit of blood from the arteries, the peripheral resistance. Thus, when the heart contracts, blood enters the arteries faster than it can leave, and the vessels stretch from the pressure. The elastic walls of the arteries snap back during diastole, but the heart contracts again before enough blood has flowed into the arterioles to completely relieve pressure in the arteries.

cardiac output

is the volume of blood pumped into the systemic circulation per minute and depends on both the heart rate and stroke volume

Hypoosmotic

less concentrated solution. Lower solute concentation, higher free h2o concentration. Water (net) flows away from this.

Lymph Nodes

organs that filter lymph and play an important role in the body's defense When the body is fighting an infection, ____ become swollen and tender

Sockeye Salmon Osmolarity

osmoregulators that migrate between rivers and the ocean

Interferon proteins

provide innate defense, interfering with viral reproduction and helping activate macrophages. The ___ limit the cell-to-cell spread of viruses, helping to control viral infection. ____ can be produced by recombinant DNA technology and have proven effective in the treatment of certain viral infections, such as hepatitis C.

Passive immunity

provides immediate, short-term protection; It is conferred naturally when IgG crosses the placenta from mother to fetus or when IgA passes from mother to infant in breast milk.

immune system

recognizes foreign bodies and responds with the production of immune cells and proteins

lymphatic system

returns fluid that leaks out from the capillary beds Fluid lost by capillaries is called lymph The ______ drains into veins in the neck Valves in lymph vessels prevent the backflow of fluid

High-density lipoprotein (HDL)

scavenges excess cholesterol for return to the liver

The humoral response is characterized by

secretion of antibodies by B cells

Humans produce...

small amounts of uric acid but excess levels lead to gout

Antigens

substances that can elicit a response from a B or T cell. T or B cells bind to ____ via _____ receptors specific to part of one molecule of that pathogen. A single ____ receptor is specific enough to bind to just one part of one molecule from a particular species of bacteria or from a particular virus.

Inflammatory Responses

such as pain and swelling, is brought about by molecules released upon injury of infection

Edema

swelling caused by disruptions in the flow of lymph

Diffusion equation

t = (x^2)/D time = (distance squared)/(diffusion constant). Small molecules can move between cells and their surroundings by diffusion. Diffusion is only efficient over small distances because the time it takes to diffuse is proportional to the square of the distance

Exchange of Substances between the blood and interstitial fluid

takes place across the thin endothelial walls of the capillaries The difference between blood pressure and osmotic pressure drives fluids out of capillaries at the arteriole end and into capillaries at the venule end Most blood proteins and all blood cells are too large to pass through the endothelium

What takes up most of a plasma cell

the ER

stroke volume

the amount of blood pumped in a single contraction

stroke

the death of nervous tissue in the brain, usually resulting from rupture or blockage of arteries in the head

Proteasome

the garbage disposal of cells. _____ and other enzymes chop up extra proteins in a cell into short peptide chains.These are then displayed on the cell surface by MHC.

Autoimmune Diseases

the immune system loses tolerance for self and turns against certain molecules of the body Autoimmune diseases include systemic lupus erythematosus, rheumatoid arthritis, insulin-dependent diabetes mellitus, and multiple sclerosis. Self-directed immune responses can cause disease. Sometimes the immune system is active against certain molecules of the body, causing an autoimmune disease. In systemic lupus erythematosus (lupus), the immune system generates antibodies against various histones and DNA released by the normal breakdown of body cells. Lupus is characterized by skin rashes, fever, arthritis, and kidney dysfunction. Rheumatoid arthritis leads to damage and painful inflammation of the cartilage and bone of joints. In Type I diabetes mellitus, the insulin-producing beta cells of the pancreas are the targets of autoimmune cytotoxic T cells. Multiple sclerosis (MS) is the most common chronic neurological disease in developed countries. In MS, T cells reactive against myelin infiltrate the central nervous system and destroy the myelin sheath that surrounds many neurons. People with MS may suffer from muscle paralysis through disruption of neuron function. Gender, genetics, and environment influence susceptibility to autoimmune disease. Members of certain families show an increased susceptibility to particular autoimmune disorders. Women are two to three times as likely as men to suffer from multiple sclerosis and rheumatoid arthritis and nine times more likely to contract lupus. Much remains to be learned about autoimmune disorders.

phagocytosis

the ingestion and digestion of foreign substances including bacteria

The "lub-dup" sound of a heart beat is caused by

the recoil of blood against the AV valves (lub) then against the semilunar (dup) valves Backflow of blood through a defective valve causes a heart murmur

Vasodilation

the relaxation of smooth muscles in the arterioles; it causes blood pressure to fall

Physiology

the scientific study of normal function in living systems.

histamine

triggers blood vessels to dilate and become more permeable

helper T cell

triggers both the humoral and cell-mediated immune responses. Signals from ____ initiate production of antibodies that neutralize pathogens and activate T cells that kill infected cells. Two requirements must be met for a _____ to activate adaptive immune responses. First, a foreign molecule must be present that can bind specifically to the antigen receptor of the T cell. Second, this antigen must be displayed on the surface of an antigen-presenting cell. The antigen-presenting cell can be a dendritic cell, macrophage, or B cell. What distinguishes an antigen-presenting cell? Most body cells have only class I MHC molecules, but antigen-presenting cells have both class I and class II MHC molecules. The class II molecules provide a molecule signature by which an antigen-presenting cell is recognized.

The pacemaker is regulated by

two portions of the nervous system: the sympathetic and parasympathetic divisions. The sympathetic division speeds up the pacemaker. The parasympathetic division slows down the pacemaker. The pacemaker is also regulated by hormones (Hormones: Epinephrine ups heart rate. 1 degree increase in temp = 10 bpm) and temperature.

Cytotoxic T cells

use toxic proteins to kill cells infected by viruses or other intracellular pathogens. Cytotoxic T cells recognize fragments of foreign proteins produced by infected cells. The activated cytotoxic T cell secretes proteins that disrupt the membranes of target cells and trigger apoptosis. To become active, cytotoxic T cells require signaling molecules from helper T cells as well as interaction with a cell that presents an antigen. The term cytotoxic refers to their use of toxic gene products to kill infected cells. Once activated, cytotoxic T cells can eliminate cells that are infected by viruses or other intracellular pathogens. Fragments of foreign proteins produced in infected host cells associate with class I MHC molecules and are displayed on the cell surface, where they can be recognized by cytotoxic T cells. As with helper T cells, cytotoxic T cells have an accessory protein that binds to the MHC molecule. This accessory protein, called CD8, helps keep the two cells in contact while the cytotoxic T cell is activated. The destruction of an infected host cell by a cytotoxic T cell involves the secretion of proteins that disrupt membrane integrity and trigger apoptosis. The death of the infected cell deprives the pathogen of a place to reproduce and exposes cell contents to circulating antibodies, which mark them for disposal. After destroying an infected cell, the cytotoxic T cell may move on and kill other cells infected with the same pathogen

Sodium Potassium Pump

uses ATP to put 2 K+ in for every 3 Na+ out

Dysfunction in ADH (vasopressin)

Decreased vasopressin release leads to diabetes insipidus, a condition featuring hypernatremia (increased blood sodium concentration), polyuria (excess urine production), and polydipsia (thirst). Excessive urination and extreme thirst (especially for cold water and sometimes ice or ice water) are typical for DI. Symptoms of diabetes insipidus are quite similar to those of untreated diabetes mellitus, with the distinction that the urine does not contain glucose and there is no hyperglycemia (elevated blood glucose). Also can be due to mutations in aquaporin channels. Can be treated pharmacologically. Alcohol can inhibit ADH release leading to excessive urinary water loss and dehydration.

B-Cells

Lymphocytes that mature in Bone marrow

T-Cells

Lymphocytes that mature in the Thymus above the heart

MHC class I & II bind to different accessory proteins

MHC Class I (cytotoxic cell) bids to CDB, TCR MHC Class II (helper T) binds to CD4 and TCR

Cardiovascular Disease

are disorders of the heart and the blood vessels These diseases range in seriousness from minor disturbances of vein or heart function to life-threatening disruptions of blood flow to the heart or brain

How does the immune system recognize bacteria/fungi?

by structures on their cell walls. Recognition proteins bind invader structure and Toll receptors, triggering immune response cascade. Innate immune responses are distinct for different classes of pathogens. Different canonical structural components are recognized by distinct genes

Platelets

fragments of cells that are involved in clotting

Sickle-cell disease

is caused by abnormal hemoglobin proteins that form aggregates The aggregates can deform an erythrocyte into a sickle shape Sickled cells can rupture or block blood vessels

Atherosclerosis

is caused by the buildup of fatty deposits (plaque) within arteries Cholesterol is a key player in the development of ______

Bowman's Capsule

cup-shaped strucutre of the nephron of a kidney which encloses the glomerulus and which filtration takes place.

Low-density lipoprotein (LDL)

delivers cholesterol to cells for membrane production

Open Circulatory System

ex: insects. Pores, tubular heart. Hemolymph in sinuses surrounding organs.

Closed Circulatory System

ex: worms and mammals. Interstitial fluid. Small branch vesels in each organ. Blood and heart. In worms: auxiliary hearts, ventral vessels, and dorsal vessel (main heart)

Allergies

exaggerated (hypersensitive) responses to antigens called allergens In localized allergies such as hay fever, IgE antibodies produced after first exposure to an allergen attach to receptors on mast cells

Osmoregulators

expend energy to control water uptake and loss in a hyperosmotic or hypoosmotic environment

Purkinje fibers

fibers in the ventricles that transmit impulses to the right and left ventricles, causing them to contract

Leukocytes

five major types: monocytes, neutrophils, basophils, eosinophils, and lymphocytes They function in defense either by phagocytizing bacteria and debris or by mounting immune responses against foreign substances They are found both in and outside of the circulatory system

Alcohol can disturb water balance by

inhibiting ADH release leading to excessive urinary water loss and dehydration.

Lymphocytes

white blood cells

Two Nephron Types

1). Cortical Nephron. 2). Juxtamedullary Nephron. Each nephron consists of a single long tubule and a ball of capillaries, called the glomerulus. The blind end of the tubule forms a cup-shaped swelling, called Bowman's capsule, that surrounds the glomerulus. Each human kidney contains about a million nephrons, with a total tubule length of 80 km.

Steps of: Figure 43.13b Immunoglobulin (antibody) gene rearrangement (part 2: polypeptide)

3). RNA processing 4). Translation

Peripheral Resistance

As a consequence of the elastic arteries working against peripheral resistance, there is substantial diastolic pressure even during diastole. Before blood has flowed from arteries into arterioles, the heart contracts again, maintaining arterial pressure. As a result, blood flows into arterioles and capillaries continuously.

Glomerulus

A ball of capillaries surrounded by Bowman's capsule in the nephron and serving as the site of filtration in the vertebrate kidney. site of initial filtrate formation. High pressure of blood. Basically non-selective. Removes wastes from blood (proteins and other beneficial macromolecules also carried over. The filtrate produced in Bowman's capsule contains salts, glucose, amino acids, vitamins, nitrogenous wastes, and other small molecules

histamine in allergies

A chemical released by the body during an inflammatory response that causes the blood vessels to dilate

Homeostatic Regulation of the Kidney

A combination of nervous and hormonal controls manages the osmoregulatory functions of the mammalian kidney These controls contribute to homeostasis for blood pressure and blood volume Antidiuretic Hormone (ADH) also called vasopressin Renin-Angiotensin-Aldosterone System (RAAS) Atrial Natriuretic Peptide (ANP)

Ureter

A duct leading from the kidney to the urinary bladder.

Renal Corpuscle

A filtering structure that consists of a Bowman's capsule and a glomerulus.

Risk Factors and Treatment of Cardiovascular Disease

A high LDL/HDL ratio increases the risk of cardiovascular disease The proportion of LDL relative to HDL can be decreased by exercise and by avoiding smoking and foods with trans fats Drugs called statins reduce LDL levels and risk of heart attacks. Inflammation plays a role in atherosclerosis and thrombus formation Aspirin inhibits inflammation and reduces the risk of heart attacks and stroke

Figure 43.13 Immunoglobulin (antibody) gene rearrangement

A receptor light chain is encoded by three gene segments: a variable (V) segment, a joining (J) segment, and a constant (C) segment. The V and J segments together encode the variable region of the receptor chain, while the C segment encodes the constant region. The light-chain gene contains a single C segment, 40 different V segments, and 5 different J segments. These alternative copies of the V and J segments are arranged within the gene in a series. Because a functional gene is built from one copy of each type of segment, the pieces can be combined in 200 (40 V x 5 J x 1 C) different ways. The number of different heavy-chain genes is even greater, resulting in more diversity

flame bulb

A structure that pushes fluid through a tubular network to regulate water retention or release. flagella looks like a flickering candle flam cellular unit that caps the smallest branches of the protonephridium. tuft of cilia projecting into tubule. beating cilia draws water and solutes from the interstitial fluid through the flame bulb

apoptosis

A type of cell death in which the cell uses specialized cellular machinery to kill itself

Central Lumen

A vessel's cavity

innate immunity

All animals have _______, a defense active immediately upon infection. Is common to all animals. These defenses are the same whether or not the pathogen has been encountered before. External barriers, formed by the skin or shell, provide a barrier to pathogens. Chemical secretions that trap or kill pathogens guard the body's entrances and exits. The internal defenses include macrophages and other phagocytic cells that ingest and destroy pathogens. An animal's immune system must detect foreign particles and tissues that invade the body, distinguishing self from nonself. This molecular recognition of nonself is accomplished by receptors that bind specifically to molecules from foreign cells or viruses. In _____, a small preset group of receptor proteins bind to molecules or structures that are absent from animal bodies but common to a group of viruses, bacteria, or other pathogens. Binding of an _____ receptor to a foreign molecule activates internal defenses, enabling responses to a very broad range of pathogens. is present before any exposure to pathogens and is effective from the time of birth. It responds to a broad range of pathogens

Which cells have class I MHC molecules on their surface?

All nucleated cells

intermittent breathers

An evolutionary variation in double circulation. Some vertebrates with double circulation are ____. For example, amphibians and many reptiles may pass long periods without gas exchange, or relying on gas exchange from another tissue, usually the skin

Figure 43.15 The specificity of immunological memory

Antibodies to A. Secondary immune response MUCH faster than primary.

Step 1 of cardiac Cycle

Atrial and ventricular diastole, 0.4 sec. Blood rushes into both atrium and ventricles.

Step 2 of Cardiac Cycle

Atrial systole and ventricular diastole. 0.1 sec. Blood is pumped into ventricles and out

Plasma Cells from B Cell Activation

B cell activation leads to a robust humoral immune response: An activated B cell gives rise to thousands of identical plasma cells. These plasma cells stop expressing a membrane-bound antigen receptor and begin producing secreted antibodies. Each plasma cell secretes approximately 2,000 antibodies every second of the cell's 4- to 5-day life span. Most antigens recognized by B cells contain multiple epitopes. An exposure to a single antigen normally activates a variety of B cells, with different plasma cells producing antibodies directed against different epitopes on the common antigen.

The Two primary solutes affecting osmolarity

NaCl and Urea

Barrier Defenses

Barrier defenses include the skin and mucous membranes of the respiratory, urinary, and reproductive tracts. Mucus traps and allows for the removal of microbes. Many body fluids including saliva, mucus, and tears are hostile to many microbes. The low pH of skin and the digestive system prevents growth of many bacteria

antibody or immunoglobulin (Ig)

Binding of a B cell antigen receptor to an antigen is an early step in B cell activation. This gives rise to cells that secrete a soluble form of the protein called an ____. _____s have the same Y shape as B cell antigen receptors but are secreted, not membrane bound. It is the ____s, rather than the B cells themselves, that actually help defend against pathogens.

Neutralization

Blocking of ability of virus to bind to a host cell

Mammalian Circulation

Blood begins its flow with the right ventricle pumping blood to the lungs via the pulmonary arteries. In the lungs, the blood loads O2 and unloads CO2. Oxygen-rich blood from the lungs enters the heart at the left atrium via the pulmonary veins. It is pumped through the aorta to the body tissues by the left ventricle. The aorta provides blood to the heart through the coronary arteries. Blood returns to the heart through the superior vena cava (blood from head, neck, and forelimbs) and inferior vena cava (blood from trunk and hind limbs). The superior vena cava and inferior vena cava flow into the right atrium.

Blood Pressure

Blood flows from areas of higher pressure to areas of lower pressure Blood pressure is the pressure that blood exerts in all directions, including against the walls of blood vessels The recoil of elastic arterial walls plays a role in maintaining blood pressure The resistance to blood flow in the narrow diameters of tiny capillaries and arterioles dissipates much of the pressure Blood, like all fluids, flows from areas of high pressure to areas of lower pressure. Blood pressure, the hydrostatic force that blood exerts against vessel walls, is much higher in arteries than in veins and is highest in arteries when the heart contracts during ventricular systole. The thick and elastic walls of arteries play a critical role in maintaining blood pressure and hence blood flow. In contrast, the blood encounters resistance as it passes through the tiny arterioles and capillaries. This resistance dissipates much of the pressure generated by the heart.

Forms of Nitrogenous Waste Diagram

Bony Fishes, Aquatic Animals: NH3 Ammoia. Mammals, amphibians, sharks, SOME bony fishes: Urea. Reptiles (birds), insects, land snails: uric acid.

Single Circulation

Bony fishes, rays, and sharks have ____ with a two-chambered heart In ____, blood leaving the heart passes through two capillary beds before returning

Figure 42.9 The structure of blood vessels

Both arteries and veins have two layers of tissue surrounding the endothelium: an outer layer of connective tissue containing elastic fibers that allow the vessel to stretch and recoil, and a middle layer containing smooth muscle and more elastic fibers. Artery walls are three times as thick as the walls of veins. The thicker walls of arteries provide strength to accommodate blood pumped rapidly and at high pressure by the heart. The elasticity (elastic recoil) of artery walls helps maintain blood pressure even when the heart relaxes.

Immunization

Both active and passive immunity can be induced artificially Active immunity can develop following immunization, introduction of antigens into the body. Both active immunity and passive immunity can be induced artificially. Active immunity can develop from the introduction of antigens into the body through immunization. The first documented immunization or vaccination was the use of cowpox virus to induce adaptive immunity against the closely related smallpox virus. Today, many sources of antigen are used to make vaccines, including inactivated bacterial toxins, killed pathogens, parts of pathogens, weakened pathogens that generally do not cause illness, and even genes encoding microbial proteins. Because all of these agents induce a primary immune response and immunological memory, an encounter with the pathogen from which the vaccine was derived triggers a rapid and strong secondary immune response. A worldwide vaccination campaign led to eradication of smallpox in the late 1970s. Routine active immunization of infants and children has dramatically reduced the incidence of diseases such as polio, measles, and whooping cough. Unfortunately, not all pathogens are easily managed by vaccination and some vaccines are not readily available in impoverished areas of the globe. Misinformation about vaccine safety and disease risk has led some parents to refuse to immunize their children with available, effective vaccines. The consequence has been a substantial and growing public health problem. In artificial passive immunization, antibodies from an immune animal are injected into a nonimmune animal. For example, humans bitten by venomous snakes are sometimes treated with antivenin, a serum from sheep or horses that have been immunized against the venom of one or more species of poisonous snakes. When injected immediately after snakebite, the antibodies in antivenin can neutralize toxins in the venom before the toxins do massive damage.

Summary of the Humoral and Cell-Mediated Immune Responses

Both the humoral and cell-mediated responses can include primary and secondary immune responses Memory cells enable the secondary response

SA node part 3

Bundle Branches pass signals to heart apex. The ECG shows a negative, downward slope to the right (a very small slope) (heart apex is the end of the heard, the bottom part)

Generation of B and T Cell Diversity

The Composition of Mammalian Blood IN CELLULAR ELEMENTS

CELLULAR ELEMENTS, 45% Cell Type / Number per microLiter of blood : Functions Leukocytes (WBCs like Basophils, Lymphocytes, Eosinophils, Neutrophils, Monocytes) / 5000-10,000 : Defense and Immunity. Platelets / 250,000-400,000: Blood clotting. Erythrocytes (RBCs) / 5,000,000 - 6,000,000 : Transport of O2 and some CO2

Immune Rejection

Cells transferred from one person to another can be attacked by immune defenses This complicates blood transfusions or the transplant of tissues or organs . Transplanted cells may be recognized as foreign and attacked by immune defenses. Like pathogens, cells from another person can be recognized as foreign and therefore be attacked by immune defenses. Skin transplanted from one person to a genetically nonidentical person will look healthy for a week or so but will then be rejected by the recipient's immune response. It remains a largely unanswered question why a pregnant woman does not reject her fetus as nonself tissue.

ADH in the collecting duct cells

Collecting duct cells has ADH receptors. ADH binds -> cAMP -> protein kinase A activate. this causes storage vesicles WITH AQUAPORIN WATER CHANNELS on their walls to exocytosis and bind onto the wall of the collecting duct cells so H2O can diffuse out of the collecting duct lumen.

Excretion in desert/marine vs freshwater animals

Desert and marine animals face desiccating environments that can quickly deplete body water Freshwater animals survive by conserving solutes and absorbing salts from their surroundings _____ rids the body of nitrogenous metabolites and other waste products

Three chambered hearts

Diffusion time is the square of distance Three-chambered hearts of amphibians and most nonbird reptiles are not inferior to the four-chambered hearts of mammals and birds, just satisfy different body needs.. Frogs and other amphibians have a three-chambered heart: two atria and one ventricle The ventricle pumps blood into a forked artery that splits the ventricle's output into the pulmocutaneous circuit and the systemic circuit When underwater, blood flow to the lungs is nearly shut off

Urethra

Duct through which urine is discharged.

Primary Immune Response

During this time, selected B and T cells give rise to their effector forms.

Antigen Recognition by B Cells and Antibodies

Each B cell antigen receptor is a Y-shaped molecule with two identical heavy chains and two identical light chains . The constant regions of the chains vary little among B cells, whereas the variable regions differ greatly. The variable regions provide antigen specificity

Figure 43.13a Immunoglobulin (antibody) gene rearrangement (part 1: pre-mRNA)

Early in B cell development, an enzyme complex called recombinase links one light-chain V gene segment to one J gene segment. This recombination event eliminates the long stretch of DNA between the segments, forming a single exon that is part V and part J. Because there is only an intron between the J and C DNA segments, no further DNA rearrangement is required. Instead, the J and C segments of the RNA transcript will be joined when splicing removes the intervening RNA. Recombinase acts randomly, linking any one of the 40 V gene segments to any one of the 5 J gene segments. Heavy-chain genes undergo a similar rearrangement. In any given cell, however, only one light-chain gene and one heavy-chain gene are rearranged. The rearrangements are permanent and are passed on to the daughter cells when the lymphocyte divides.

Vein Structure Descrip

Endothelium, thin, on the inside. The hole is much bigger than that of the artery. There's valves inside as well. Smooth muscle around the endothelium is very thin. Connective tissue around teh smooth muscle is very thin as well. a bit more than 100 micrometers in diameter.

Stem Cells and the Replacement of Cellular Elements

Erythrocytes, leukocytes, and platelets all develop from a common source of stem cells in the red marrow of bones, especially ribs, vertebrae, sternum, and pelvis The hormone erythropoietin (EPO) stimulates erythrocyte production when O2 delivery is low Physicians can use recombinant EPO to treat people with conditions such as anemia

Diverse excretory systems are variations on a tubular theme

Excretory systems regulate solute movement between internal fluids and the external environment These systems are central to homeostasis

Exertion, Stress, and the Immune System

Exertion and stress influence immune system function. Moderate exercise improves immune system function and reduces the risk of infection. Exercise to the point of exhaustion leads to more frequent infections with more severe symptoms. Physiological stress disrupts immune system regulation by altering the interplay of the hormonal, nervous, and immune systems. Rest is important for immunity: adults who averaged fewer than seven hours a night of sleep got sick three times as often when exposed to a cold virus as individuals who averaged at least eight hours of sleep. Moderate exercise improves immune system function Psychological stress has been shown to disrupt immune system regulation by altering the interactions of the hormonal, nervous, and immune systems Sufficient rest is also important for immunity

Blood Flow against Gravity

Fainting is caused by inadequate blood flow to the head Animals with long necks require a very high systolic pressure to pump blood a great distance against gravity Blood is moved through veins by smooth muscle contraction, skeletal muscle contraction, and expansion of the vena cava with inhalation One-way valves in veins prevent backflow of blood

Phagocytosis

Figure 43.19 A Phagocytosis enables macrophages and dendritic cells to present antigens to and stimulate helper T cells, which in turn stimulate B cells whose antibodies contribute to phagocytosis. This positive feedback between innate and adaptive immunity contributes to a coordinated, effective response to infection. Antibodies can also bring about the death of infected body cells. When a virus uses a cell's biosynthetic machinery to produce viral proteins, these viral products can appear on the cell surface. If antibodies specific for epitopes on these viral proteins bind to the exposed proteins, the presence of bound antibody at the cell surface can recruit a natural killer cell. The natural killer cell then releases proteins that cause the infected cell to undergo apoptosis. ntibody-mediated mechanisms of antigen disposal

Ascending Limb of Loop of Henle

Filtrate returns to renal cortex Transport epithelium contains ion channels but not water channels (impermeable to water, a rare event) Thin segment: Near tip, NaCl diffuses out into interstitial fluid and maintains osmolarity of interstitial fluid in renal medulla Thick segment: Near distal tubule, NaCl transported out requiring energy for active transport. Loss of NaCl to interstitial fluid but no water loss. Filtrate becomes more dilute as it moves up cortex in ascending loop.

Nephrons: Close Look

Filtration occurs as blood pressure forces fluid from the blood in the glomerulus into the lumen of Bowman's capsule. The porous capillaries, along with specialized capsule cells, are permeable to water and small solutes but not to blood cells or large molecules such as plasma proteins. The filtrate in Bowman's capsule contains salt, glucose, amino acids, vitamins, nitrogenous wastes such as urea, and other small molecules. Because filtration of small molecules is nonselective, the mixture mirrors the relative concentrations of solutes in blood plasma.

Key functions of most excretory systems

Filtration: Filtering of body fluids Reabsorption: Reclaiming valuable solutes Secretion: Adding nonessential solutes and wastes to the filtrate Excretion: Processed filtrate containing nitrogenous wastes is released from the body

The Kidneys

Function in both osmoregulation and Consists of vast tubule array Supplied by renal artery Drained by renal vein Receives 25% blood supply leaving heart Filters 1600 L per day 300 passes

Osmoregulation in a freshwater fish

Gain of water and some ions in food through mouth. Uptake of salt ions by fills. Osmotic water gain through gills and other parts of body surface. Excretion of salt ions and large amounts of water in dilute urine from kidneys.

Osmoregulation in a marine fish

Gain of wter and salt ions from food AND from drinking water. Excretion of salt ions from gills. Osmotic water loss through gills and other parts fo body surface. Excretion of salt ions and small amounts of water in scanty urine from kidneys.

Experiment : How to visualize innate immune response?

Green Fluorescent Protein, genetically-encoded fluorescent tag.

What does the filtrate include after the glomerulus?

H2O, Salts (including NaCL), HCO3-, H+, Urea, Glucose, amino acids, some drugs.

AIDS and HIV

HIV infection leads to acquired immune deficiency syndrome (AIDS) People with AIDS are highly susceptible to opportunistic infections and cancers that take advantage of an immune system in collapse The spread of HIV is a worldwide problem The best approach for slowing this spread is education about practices that transmit the virus

Osmotic pressure effects cell shape

Hypotonic: Lysed Isotonic: Normal Hypotonic: Shriveled

The Composition of Mammalian Blood IN PLASMA

IN PLASMA, 55%. Constituent: Function Water: Solvent Ions (blood electrolytes like Na+, K, Ca+, Mg 2+, Cl-, Bicarbonate): Osmotic balance, pH buffering, and regulation of membrane permeability Plasma proteins (like albumin, antibodies [aka immunoglobulins], apolipoproteins, fibrinogen): Osmotic balance, pH buffering. defense, lipid transport, and clotting RESPECTIVELY. Substances transported by blood - nutrients (glucose, fatty acids, vitamins), waste products of metabolism, respiratory gases (O2 and CO2), Hormones.

In text, the SA node cycle

Impulses from the SA node travel to the atrioventricular (AV) node At the AV node, the impulses are delayed and then travel to the Purkinje fibers that make the ventricles contract

opsonization

In _____, antibodies bound to antigens on bacteria present a readily recognized structure for macrophages or neutrophils and therefore increase/trigger phagocytosis. Each antibody has two antigen-binding sites, and antibodies may facilitate phagocytosis by linking bacterial cells, virus particles, or other foreign substances into aggregates. Antibodies may work together with the proteins of the complement system to dispose of pathogens. The name complement reflects the fact that these proteins increase the effectiveness of antibody-directed attacks on bacteria.Antigen-antibody complexes may bind to a complement protein—which triggers a cascade of complement protein activation Binding of a complement protein to an antigen-antibody complex on a foreign cell (or an enveloped virus) triggers a cascade in which each protein of the complement system activates the next protein. Ultimately, activated complement proteins generate a membrane attack complex that forms a pore in the membrane of the foreign cell. Ions and water rush into the cell, causing it to swell and lyse. Ultimately a membrane attack complex forms a pore in the membrane of the foreign cell, leading to its lysis

antigen presentation

In infected cells, MHC molecules bind and transport antigen fragments to the cell surface, a process called ______.

Proliferation of B Cells and T Cells

In the body there are few lymphocytes with antigen receptors for any particular epitope. In the lymph nodes, an antigen is exposed to a steady stream of lymphocytes until a match is made. This binding of a mature lymphocyte to an antigen initiates events that activate the lymphocyte. Only a tiny fraction of antigen receptors are specific for epitopes on a given antigen. Why is adaptive immunity so effective? First, in the lymph nodes, an antigen is presented to a steady stream of lymphocytes until a match is made. The second part of the answer lies in changes in cell number and behavior triggered by the binding of antigen to lymphocyte. The binding of an antigen receptor to an epitope on a specific antigen initiates events that activate the lymphocyte.

Dangers of Immune Response

Inflammation can be either local or systemic (throughout the body). Fever is a systemic inflammatory response triggered by substances released by macrophages in response to certain pathogens. Septic shock is a life-threatening condition caused by an overwhelming inflammatory response

Concept 43.1: In innate immunity, recognition and response rely on traits common to groups of pathogens

Innate immunity is found in all animals and plants In vertebrates, innate immunity is a first response to infections and also serves as the foundation of adaptive immunity

Endothelium

Lining the lumen of all blood vessels, including capillaries, is an _____, a single layer of flattened cells that minimizes resistance to blood flow. The smooth surface of the ______ minimizes resistance to blood flow. Structural differences correlate with the different functions of capillaries, arteries, and veins.

Kidneys

Kidneys, the excretory organs of vertebrates, function in both excretion and osmoregulation The numerous tubules of kidneys are highly organized The vertebrate excretory system also includes ducts and other structures that carry urine from the tubules out of the kidney and out of the body. The kidneys of vertebrates usually function in both osmoregulation and excretion. Like the excretory organs of most animal phyla, kidneys are built of tubules. The vertebrate excretory system includes a dense network of capillaries intimately associated with the tubules, along with ducts and other structures that carry urine out of the tubules and kidney and eventually out of the body. The kidneys of vertebrates are nonsegmented. However, hagfishes, chordates that lack vertebrae, have kidneys with segmentally arranged excretory tubules. This suggests that the excretory segments of vertebrate ancestors were segmented.

Stenohaline

Most animals are ____; they cannot tolerate substantial changes in external osmolarity

filtrate

Most excretory systems produce urine by refining a ___ derived from body fluids

Marine Animals

Most marine invertebrates are osmoconformers Many marine vertebrates and some marine invertebrates are osmoregulators Marine bony fishes are hypoosmotic to seawater They balance water loss by drinking large amounts of seawater and eliminating the ingested salts through their gills and kidneys

Salt secretion in the nasal glands of a marine bird

Nostril has a nasal salt gland that secretes salt. In the nasal salt gland, the secretory tubule is close to the transport epithelium, which is close to the capillary. The salts go from the blood, through the transport epithelium secretory cells, and then into the lumen of the secretory tubule.

clonal selection

Once activated, a B or T cell undergoes multiple cell divisions (_____) to produce a clone of identical cells. the result of this proliferation is a clone, a population of cells that are identical to the original cell. The proliferation of an activated lymphocyte into a clone of cells in response to binding to an antigen is called ______. An encounter with an antigen selects which lymphocyte will divide to produce a clonal population of thousands of cells, all specific for a particular epitope on that antigen.

Precapillary Sphincters

One of the functions of _________ is to close off capillaries that aren't being used to cause an increase in pressure - which is used to help maintain blood pressure. band of smooth muscle that adjusts the blood flow into each capillary

Antidiuretic hormone, ADH,aka vasopressin

Osmoreceptor cells in the hypothalamus monitor blood osmolarity and regulate release of ___ from the posterior pituitary When osmolarity rises above its set point, ____ release into the blood stream increases. Produced in hypothalamus and stored in posterior pituitary gland. Binding of ADH to receptor molecules leads to a temporary increase in the number of aquaporin proteins in the membrane of collecting duct cells This reduces urine volume and lowers blood osmolarity

Energetics of Osmoregulation

Osmoregulators must expend energy to maintain osmotic gradients The amount of energy differs based on How different the animal's osmolarity is from its surroundings How easily water and solutes move across the animal's surface The work required to pump solutes across the membrane

Cellular Innate Defenses

Pathogens entering the mammalian body are subject to phagocytosis. Phagocytic cells recognize groups of pathogens using TLRs, Toll-like receptors. Each mammalian TLR, or Toll-like receptor, binds to fragments of molecules characteristic of a set of pathogens.

Antimicrobial Peptides and Proteins

Peptides and proteins function in innate defense by attacking pathogens or impeding their reproduction. Interferon proteins. About 30 proteins make up the complement system, which causes lysis of invading cells and helps trigger inflammation. Some of these molecules function like the antimicrobial peptides of insects, damaging broad groups of pathogens by disrupting membranes. Others, including the interferons and complement proteins, have activities unique to vertebrate immune systems.

TLR (toll-like receptor)

Phagocytic cells recognize groups of pathogens using _____. Each mammalian ____ binds to fragments of molecules characteristic of a set of pathogens.

vasoconstriction

Physical or emotional stress can trigger nervous and hormonal responses that cause smooth muscles in arteriole walls to contract, a process called ________. Contraction of smooth muscles in the walls of arterioles constricts these vessels, increasing blood pressure upstream in the arteries. Homeostatic mechanisms regulate arterial blood pressure by altering the diameter of arterioles _______ is the contraction of smooth muscle in arteriole walls; it increases blood pressure

Osmoregulation

Physiological systems of animals operate in a fluid environment Relative concentrations of water and solutes must be maintained within fairly narrow limits ____ controls solute concentrations and balances water gain and loss. is based largely on balancing the uptake and loss of water and solutes The driving force for movement of solutes and water is a concentration gradient of one or more solutes across the plasma membrane

Urea

Primary form of nitrogenous waste in mammals Produced in liver in a metabolic process that combines ammonia and CO2 Urea has low toxicity Somewhat energy demanding

Uric Acid

Primary nitrogenous waste of birds, insects, reptiles Non-toxic Does not dissolve in water Requires very little water to dispose High energy demand

Hearts are found in all closed circulatory systems

Pumps create pressure gradients in fluids. Fluids (like blood) flow down pressure gradients. So, at the downstream end of blood vessels, BP is low. Heart restores BP to enable re-circulation.

Blood Flow Velocity Equation

Q = (Delta P)/R Flow = Pressure difference / Resistance Velocity of blood flow is slowest in the capillary beds, as a result of the high resistance and large total cross-sectional area Blood flow in capillaries is necessarily slow for exchange of materials

Angiotensin II

Raises blood pressure and decreases blood flow to the kidneys Stimulates the release of the hormone aldosterone, which increases blood volume and pressure

LDL and HDL ratio

Risk for heart disease increases with a high LDL to HDL ratio Inflammation is also a factor in cardiovascular disease

How is the kidney supplied by blood without interfering with filtration?

Role of vasa recta Note that ascending and descending vessels of vasa recta carry blood in opposite directions through kidney. Descending vessel loses water and gains NaCl but this is reversed as blood flows back toward cortex. Balanced net outcome.

Granzymes

Serine proteases that are released by cytoplasmic granules within cytotoxic T cells and natural killer cells. Their purpose is to induce apoptosis within virus-infected cells, thus destroying them

SA node part 2

Signals are delayed at AV node. The ECG shows a flat, short line.

SA node part 4

Signals spread throughout ventricles (through the Purkinje fibers). There is a huge spike in the ECG, which soon drops to negative before going back to the straight line again.

anhydrobiosis

Some aquatic invertebrates in temporary ponds lose almost all their body water and survive in a dormant state. EG THE TARDIGRADE

Maintaining the Heart's Rhythmic Beat

Some cardiac muscle cells are autorhythmic, meaning they contract without any signal from the nervous system The sinoatrial (SA) node, or pacemaker, sets the rate and timing at which cardiac muscle cells contract Impulses that travel during the cardiac cycle can be recorded as an electrocardiogram (ECG or EKG)

memory cells

Some cells from the clone become long-lived ______ that can give rise to effector cells if the same antigen is encountered again

effector cells

Some cells from the clone become short-lived ____ that act immediately against the antigen. ______ are plasma cells that secrete antibodies. The _____ forms of B cells are plasma cells, which secrete antibodies. The _____ forms of T cells are helper T cells and cytotoxic T cells.

Figure 43.7: The Human Lymphatic System

Some macrophages reside in the lymph nodes. Dendritic cells migrate to lymph nodes after interaction with pathogens. Some macrophages reside in the lymph nodes, where they encounter and engulf pathogens that have flowed from the interstitial fluid into the lymph. Dendritic cells reside outside the lymphatic system but migrate to lymph nodes after interaction with pathogens. Within the lymph node, dendritic cells interact with other immune cells, stimulating adaptive immunity. Adenoid, Tonsils, lymphatic vessels, thymus, peyer's patches (in small intestine), appendix, lymph nodes, spleen.

Evasion of Innate Immunity by Pathogens

Some pathogens avoid destruction by modifying their surface to prevent recognition or by resisting breakdown following phagocytosis. Tuberculosis (TB), one such disease, kills more than a million people a year

Latency

Some viruses may remain in a host in an inactive state called latency Herpes simplex viruses can be present in a human host without causing symptoms

Juxtaglomerular apparatus

Specialized cells next to the glomerulus that help to regulate blood pressure

Survey of Excretory Systems

Systems that perform basic excretory functions vary widely among animal groups They usually involve a complex network of tubules

Concept 43.2: In adaptive immunity, receptors provide pathogen-specific recognition

The adaptive response relies on two types of lymphocytes, or white blood cells. Lymphocytes that mature in the Thymus above the heart are called T cells, and those that mature in Bone marrow are called B cells. Lymphocytes of a third type remain in the blood and become the natural killer cells active in innate immunity.

Figure 43.10 Antigen recognition by B cells and antibodies

The antigen-binding site of a membrane-bound antibody has a unique shape that provides a lock-and-key fit for a particular epitope. Noncovalent bonds between an epitope and the binding surface provide a stable and specific interaction. Picomolar affinity! Differences in the amino acid sequences of variable regions provide the variation in binding surfaces that enables this highly specific binding. B cell antigen receptors and antibodies bind to intact antigens on the surface of pathogens or free in body fluids.

systole

The contraction, or pumping, phase

cytotoxic t cell

The cytotoxic t cell attaches to the infected cell, which has presented an antigen fragment with a CLASS I MHC MOLECULE. It is attached with both an accessory protein and an antigen receptor to the class I MHC molecule/the antigen fragment. The cytotoxic t cell releases granzymes and perforin, which make pores in theinfected cell and break down the infected cell. Then the cyto t cell leaves. lol.

Adaptive immunity defends against infection of body fluids and body cells

The defenses provided by B and T lymphocytes can be divided into humoral immune response and the cell-mediated immune response. Both responses include a primary immune response and a secondary immune response enabled by memory cells.

endothelium

The epithelial layer that lines blood vessels is called the _____. It is smooth and minimizes resistance

Cancer and Immunity

The frequency of certain cancers increases when adaptive immunity is inactivated 15-20% of all human cancers involve viruses The immune system can act as a defense against viruses that cause cancer and cancer cells that harbor viruses In 2006, a vaccine was released that acts against human papillomavirus (HPV), a virus associated with cervical cancer

cardiac cycle

The heart contracts and relaxes in a rhythmic cycle called the ____

Mammals

The juxtamedullary nephron is key to water conservation in terrestrial animals Mammals that inhabit dry environments have long loops of Henle, while those in fresh water have relatively short loops

The Influence of Evolution and Environment on Nitrogenous Wastes

The kinds of nitrogenous wastes excreted depend on an animal's evolutionary history and habitat, especially water availability Another factor is the immediate environment of the animal egg The amount of nitrogenous waste is coupled to the animal's energy budget

Concept 42.2: Coordinated cycles of heart contraction drive double circulation in mammals

The mammalian cardiovascular system meets the body's continuous demand for O2

Kidney Structure

The mammalian kidney has two distinct regions: an outer renal cortex and an inner renal medulla. Both regions are packed with microscopic excretory tubules, nephrons, and their associated blood vessels.

Solute Gradients and Water Conservation

The mammalian kidney's ability to conserve water is a key terrestrial adaptation Hyperosmotic urine can be produced only because considerable energy is expended to transport solutes against concentration gradients The two primary solutes affecting osmolarity are NaCl and urea

Fluid Movement and Blood

The observation that blood travels more than a thousand times faster in the aorta than in capillaries follows from the laws describing fluid movement through pipes. If a pipe's diameter changes over its length, a fluid will flow through narrower segments faster than it flows through wider segments because the volume of flow per second must be constant throughout the entire pipe.

The interrelationship of cross-sectional area of blood vessels, blood flow velocity, and blood pressure (detail)

The resulting slow flow rate and thin capillary walls promote the exchange of substances between the blood and interstitial fluid by providing time for exchange to occur. As blood leaves the capillary beds and passes to venules and veins, it speeds up again as a result of the reduction in total cross-sectional area.

Concept 42.3: Patterns of blood pressure and flow reflect the structure and arrangement of blood vessels

The physical principles that govern movement of water in plumbing systems apply to the functioning of blood vessels

Antibodies as Tools

The power of antibody specificity and antigen-antibody binding has been harnessed in research, diagnosis, and therapy. Some antibody tools are polyclonal: They are the products of many different clones of plasma cells, each specific for a different epitope. In contrast, other antibody tools are monoclonal: They are prepared from a single clone of B cells grown in culture. The monoclonal antibodies produced by such a culture are identical and specific for the same epitope on an antigen. Monoclonal antibodies have provided the basis for many recent advances in biomedicine in both diagnosis and treatment. Home pregnancy kits use monoclonal antibodies to detect human chorionic gonadotropin (HCG). HCG is produced as soon as an embryo implants in the uterus, and the presence of this hormone in a woman's urine is a reliable indicator for a very early stage of pregnancy. Monoclonal antibodies are being used to treat many human diseases. For this therapy, researchers use mouse B cell clones to identify antibodies specific for an epitope on diseased cells. The mouse antibody genes are altered to code for antibodies that appear less "foreign" to the human adaptive immune defenses. Scientists then use the "humanized" genes to produce large amounts of antibody for injecting into patients. Antibodies produced by an animal after exposure to an antigen are the products of many different clones of plasma cells However, monoclonal antibodies can be prepared from a single clone of B cells grown in culture These antibodies are identical and specific for one epitope

diastole

The relaxation, or filling, phase

epitope

The small accessible part of an antigen that binds to an antigen receptor is called a ____. Each individual B or T cell is specialized to recognize a specific type of molecule. The cells of the immune system can produce millions of different antigen receptors, but the antigen receptors made by a single B or T cell are all identical. The antigen receptors of B cells and T cells have similar components but they encounter antigens in different ways

Efferent Arteriole

The small artery that carries blood away from the capillaries of the glomerulus.

The Mammalian Heart: A Closer Look

The two atria have relatively thin walls and serve as collection chambers for blood returning to the heart. The ventricles have thicker walls and contract much more forcefully

ammonia (NH3)

The type and quantity of an animal's waste products may greatly affect its water balance Among the most significant wastes are nitrogenous breakdown products of proteins and nucleic acids. Some animals convert toxic ___ to less toxic compounds prior to excretion. Tolerated in very low concentrations Excretion requires large amounts of water Common in aquatic species Most ammonia is lost as NH4+ across epithelium of gills (because NH3 is a proton acceptor). 200m tons/yr 1% world's energy

How does an albatross drink salt water without ill effect?

The wandering albatross, Diomedea exulans, remains at sea all year long, drinking only seawater. Homeostasis requires osmoregulation, the general process by which animals control solute concentrations and balance water gain and loss. The physiological systems of animals operate within a fluid environment. The relative concentrations of water and solutes must be maintained within narrow limits, despite variations in the animal's external environment. Ions such as sodium and calcium must be maintained at concentrations that permit normal activity of muscles and neurons. Desert and marine animals face the possibility of dehydration and must conserve water. Freshwater animals are threatened with dilution of body fluids and must conserve solutes and absorb salts. Metabolism also creates the problem of disposing of hazardous metabolites from the breakdown of proteins and nucleic acids. The breakdown of nitrogenous molecules releases ammonia, a very toxic compound. Several different strategies have evolved for excretion, the removal of nitrogen-containing waste products of metabolism.

Antigenic Variation

Through antigenic variation, some pathogens are able to change epitope expression and prevent recognition The human influenza virus mutates rapidly, and new flu vaccines must be made each year Human viruses occasionally exchange genes with the viruses of domesticated animals This poses a danger as human immune systems are unable to recognize the new viral strain.

Blood Groups

To avoid a blood transfusion being recognized as foreign by the recipient's immune system, ABO blood groups of the donor and recipient must be taken into account. Red blood cells are designated as type A if they have the type A carbohydrate on their surface. The type B carbohydrate is found on type B red blood cells; both A and B carbohydrates are found on type AB red blood cells; and neither carbohydrate is found on type O red blood cells. Consider the immune response of someone with type A blood. Certain bacteria normally present in the body have epitopes very similar to the A and B carbohydrates. By responding to the bacterial epitope similar to the B carbohydrate, a person with type A blood makes antibodies that will react with the type B carbohydrate. No antibodies are made against the bacterial epitope similar to the type A carbohydrate because lymphocytes reactive with the body's own molecules are inactivated or eliminated during development. If the person with type A blood receives a transfusion of type B blood, that person's anti-B antibodies cause an immediate and devastating transfusion reaction. The transfused red blood cells undergo lysis, which can lead to chills, fever, shock, and kidney malfunction. Anti-A antibodies in the donated type B blood will act against the recipient's type A red blood cells. Antigens on red blood cells determine whether a person has blood type A (A antigen), B (B antigen), AB (both A and B antigens), or O (neither antigen). Antibodies to nonself blood types exist in the body.Transfusion with incompatible blood leads to destruction of the transfused cells

What does b cell activation depend on? An exception?

Usually requires antigen binding to both B cell receptor binding and helper T cell Exception : antigens that trigger innate defenses can activate B cell response without helper T cell

width of capillary

a few micrometers (5 micrometers?)

Concept 42.4: Blood components function in exchange, transport, and defense

With open circulation, the fluid is continuous with the fluid surrounding all body cells The closed circulatory systems of vertebrates contain a more highly specialized fluid called blood

B- Cell Shape

Y-shaped receptor

heart rate

also called the pulse, is the number of beats per minute

lysozyme

an enzyme that breaks down bacterial cell walls

what are allergens in the class of?

antigens.

Angina pectoris

chest pain caused by partial blockage of the coronary arteries

Neutrophils

circulate in the blood. phagocytic

hemocytes

circulate within hemolymph and carry out phagocytosis. In insects, circulating cells called hemocytes travel through the hemolymph, the insect circulatory fluid. Some hemocytes can phagocytose pathogens. Other hemocytes trigger the production of chemicals that kill pathogens and entrap parasites. Hemocytes also secrete antimicrobial peptides that disrupt the plasma membranes of fungi and bacteria. Hemocytes and other cells secrete antimicrobial peptides that bind to and destroy bacteria and fungi by disrupting their plasma membranes.

Osmoconformers

consisting only of some marine animals, are isoosmotic with their surroundings and do not regulate their osmolarity

Complement System

consists of roughly 30 proteins in blood plasma that circulate in an inactive state and are activated by substances on the surface of many pathogens. Activation results in a cascade of biochemical reactions that lead to lysis of invading cells. the _______ functions in inflammation as well as in adaptive defenses.

Venules

converge into veins and return blood from capillaries to the heart

Active immunity

develops naturally; a pathogen invades the body and elicits a primary or secondary immune response

Eosinophils

discharge destructive enzymes next to big invaders (e.g. worms)

T-cell shape

i-shaped receptor

adaptive immunity

is found only in vertebrates. are activated after innate immune defenses and develop more slowly. These ____ defenses are enhanced by previous exposure to the infecting pathogen. Animals with _____ have a large number of receptors, each recognizing a feature typically found only on a particular molecule in a particular microbe. As a result, ____ systems detect pathogens with tremendous specificity. develops after exposure to agents such as microbes, toxins, or other foreign substances. It involves a very specific response to pathogens

secondary immune response

memory cells facilitate a faster, more efficient response

hOW IS osmolarity measured

milliOsmoles per L (1 mOsm/L = 10-3M) Human blood = 300 mOsm/L Sea water = 1000 mOsm/L

hyperosmotic

more concentrated solution. Higher solute concentration; lower free h20 concentration. Water (net) flows toward this.

The Structure of a T-Cell Antigen REceptor

not y-shaped. alpha and beta chain. 2 variable regions, 2 constant reions; one transmembrane region and one antigen binding site. disulfide bridge as well.

humoral immune response

occurs in the blood and lymph. antibodies help neutralize or eliminate toxins and pathogens in the blood and lymph.

macrophages

phagocytic. are found throughout the body & organs (spleen).

cell mediated immune response

specialized T cells destroy affected host cells.

Dendritic cells

stimulate development of adaptive immunity (control system)

EPO aka erythropoietin

stimulates erythrocyte production when O2 delivery is low. Physicians can use recombinant ____ to treat people with conditions such as anemia

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