Majors Bio. Test 4

Structure of villi

Each villus has a •Capillary - allows for nutrients other than fat to be absorbed into blood •Lacteal (part of lymphatic system)- allows for larger fat particles to enter, eventually dumped into blood

Describe the reversible reaction between hemoglobin and oxygen

Oxygen-hemoglobin dissociation curve: When the pressure (amount) of O2 is high, more O2 binds to hemoglobin When the pressure (amount) of O2 is low, less O2 binds to hemoglobin Sigmoidal curve due to cooperation: the shape of hemoglobin changes as oxygen loads and unloads •When one site binds oxygen, the probability that the remaining unoccupied sites that will bind to oxygen will increase. The importance of cooperative behavior is that it allows hemoglobin to be more efficient in transporting oxygen.

General function of accessory organs

The accessory organs (pancreas, liver, gallbladder) secrete substances into the duodenum - first part of intestine

Systemic blood pressure

The greater the cardiac output and the higher the resistance, the higher the blood pressure. Systemic blood pressure refers to the pressure exerted on blood vessels in systemic circulation. Arterial blood pressure is a function of •How hard the heart is working •How constricted or dilated the various arterioles are Garden hose analogy (slides 43-45 on CH. 48 PowerPoint)

Functions of the four heart chambers

The right atrium receives oxygen-poor blood from the body and pumps it to the right ventricle. The right ventricle pumps the oxygen-poor blood to the lungs. The left atrium receives oxygen-rich blood from the lungs and pumps it to the left ventricle. The left ventricle pumps the oxygen-rich blood to the body.

Endothermic homeotherms (birds and mammals)

They can quickly adjust the body's mechanisms for retaining or releasing heat so that body temperature remains within narrow range, which ensures body's chemical reactions are at optimal levels when environment imposes extreme challenges Example: •A suddenly awakened mammal is instantly capable of intense activity •A reptile must wait until it can warm itself using the environment

Tracheae (found in insects) for gas exchange

Tiny openings called spiracles on the body surface lead to tracheae that branch into tracheoles terminating near every body cell. Tracheae have a small amount of fluid for gas to diffuse into them. Body muscle movements draw air in and out of tracheae. Oxygen diffuses directly from air to tracheae to tracheoles to body cells Very efficient - supports insect flight muscles, with the highest metabolic rate known

Describe the branching tubes that facilitate air flow in mammalian respiration

Trachea branches into two bronchi Bronchioles - surrounded by circular muscle to dilate or constrict passage Alveoli - site of gas exchange •One cell thick •Type I cells - gases diffuse across •Type II cells - secretory cells

Structure of the vertebrate heart

Two sides of the heart are separated by a wall called the septum Double circulation with four chambers •Right atrium •Right ventricle •Left atrium •Left ventricle The vertebrate heart is a myogenic heart, which means that it beats on its own, is electrically excitable, and generates its own action potentials. (In contrast, neurogenic hearts of arthropods require regular electrical impulses from the nervous system) The sinoatrial node (SA node) functions as the pacemaker •Collection of modified cardiac cells that spontaneously and rhythmically generate action potentials

Name the primary components of the urinary system in mammals, and describe the major anatomical features of the human kidney

Urinary system •Two kidneys •Urine flows from kidneys through ureters into urinary bladder •Urine eliminated via the urethra The kidney •Renal cortex - primary site of blood filtration •Renal medulla - filtrate becomes concentrated by reabsorption

Explain why some nutrients do not require digestive prior to being absorbed

Vitamins, minerals, and water do not require digestion, instead they are absorbed in their complete forms. Water-soluble vitamins absorbed by diffusion or active transport Fat-soluble vitamins (A,D,E, and K) follow pathway for lipid absorption Small amounts of water absorbed in stomach but most in small intestine

Mouth (+functions of saliva)

Where ingestion begins. The presence of food stimulates salivary glands in terrestrial vertebrates Saliva contains proteins, mucus, and antibacterial agents Functions of saliva: •Moisten and lubricate food to facilitate swallowing •Dissolve food particles to facilitate taste •Kill ingested bacteria •Initiate digestion of carbohydrates with amylase

Define ventilation

the process of bringing oxygenated water or air into contact with a gas-exchange organ

Urea

•All mammals, most amphibians, some marine fishes, some reptiles, some terrestrial invertebrates have this nitrogenous waste •Produced by metabolic conversion to NH3 (Ammonia) •Less toxic than ammonia •Doesn't need as large a volume of water for excretion •Animals can tolerate some urea accumulation •Drawback is conversion of ammonia to urea requires ATP' Moderate amount of water needed for excretion

Describe the process of elimination in metanephridia

•Found in annelids •Tubular network beginning in funnel-like structure called nephrostome •Pairs located in each body segment •Collect coelomic fluid containing nitrogenous wastes •Na+, Cl-, and other solutes reabsorbed along tubule •Nitrogenous wastes excreted through nephridiopores in body wall (osmoregulatory)

Describe the process of elimination in protonephridia

•Found in flatworms •Simplest filtration mechanism in invertebrates •Series of branching tubules filter fluids from body cavity using beating of ciliated cells (flame cells) •Solutes are reabsorbed •Excess water and some wastes empty through openings in body wall called nephridiopores •Osmoregulatory - nitrogenous wastes diffuse out of body

Describe the process of elimination in malpighian tubules

•Found in insects •Uses secretion and not filtration •Extensive series of narrow tubes called Malpighian tubules arises from the midgut and extends into hemolymph •Cells lining tubules actively transport ions and uric acid from hemolymph into lumen •Creates osmotic gradient drawing water and solutes into tubule •Moves to hindgut where water and solutes reabsorbed •Nitrogenous wastes and others excreted together with feces through anus •Urine is either isosmotic or hyperosmotic

Four phases of food processing in animals

•Ingestion - food is taken into the body and moves into a digestive cavity (usually called the alimentary canal) •Digestion - Food is broken down into smaller molecules •Absorption - ions, water, and small molecules diffuse or are transported into the circulatory system •Egestion - undigested materials and other wastes are passed from the body

Ammonia (NH3) and ammonium ions (NH4+)

•Most toxic of nitrogenous wastes •Disrupt pH of body fluids, ion electrochemical gradients, and many redox reactions •Animals that excrete wastes in this form typically live in water •Aquatic animals can excrete it as soon as it forms, so the chief advantage of this nitrogenous waste is that energy is not required for conversion to a less toxic product High amount of water needed for excretion

Define a nutrient and nutrition

•Nutrient - any substance taken in by an organism that is needed for survival, growth, development, tissue repair, or reproduction •Nutrition - process of consuming and using food and nutrients

Intracellular digestion

•Only in some very simple invertebrates (sponges and some single-celled organisms) •Uses phagocytosis to bring food particles directly into a cell •Cannot meet metabolic demands of active animal for long •No mechanism for storing food

Gastrovascular cavity

•Simplest form of extracellular digestion (the other form is the alimentary canal) •Occurs in invertebrates such as flatworms and cnidarians •One opening is entry and exit •Functions in both digestion and distribution of nutrients •Food particles eventually phagocytosed for further intracellular digestion

Essential amino acids

- Essential amino acids are the nine amino acids that are needed but cannot be made by the body (the other eleven can be made by the body). - Essential amino acids are not stored. All 20 amino acids can be found in meat. Examples of essential amino acids: histidine, valine, tryptophan

Essential fatty acids

- Essential fatty acids are fatty acids that cannot be synthesized by animal cells. - Unsaturated fatty acids primarily found in plants (strict carnivores obtain them from fish or adipose tissue of birds) Example of essential fatty acids: Linoleic acid (vital precursor to arachidonic acid)

Vitamins

- Important organic nutrients that serve as coenzymes - Water-soluble vitamins (like vitamin C) are not stored - Fat-soluble vitamins (like vitamin A) are stored in adipose tissue Examples of vitamins: vitamin C, folic acid (water-soluble), vitamin A

single circulation (found in fish)

- Single atrium collects blood from tissues, and a single ventricle pumps blood out of the heart. Arteries carry blood away from the heart to the gills. The blood picks up oxygen, and drops off carbon dioxide in the gills. Freshly oxygenated blood continues on through arteries to other body tissues. Oxygen and nutrients are delivered to tissues, and carbon dioxide diffuses into blood. Partially deoxygenated blood returns to the heart via veins. - In single circulation, respiratory surfaces function best when the blood flowing through them is maintained at low pressure. Thus, the fish heart does not generate high pressure when pumping blood to the gills. This means that blood pressure leaving the gills will also be low, which limits rate at which oxygenated blood can be delivered to body. TLDR: In single circulation, the blood passes through a single circuit - where blood is pumped by the heart to the gills for oxygenation, after which the blood flows to the rest of the body and back to the heart

Describe the process of blood clotting in mammals

1.) An injury ruptures a blood vessel 2.) Platelets stick to each other and to collagen fibers, forming a plug. Blood loss is reduced. 3.) Fibrin forms a meshwork that traps erythrocytes and platelets, forming a clot that seals the wound.

Describe the three factors that determine how much gas dissolves in a solution

1.) Pressure of the gas - As the pressure of a gas that comes into contact with water increases, more of that gas will dissolve, up to a limit that is specific for each gas at a given temperature. 2.) Temperature of water - More of a gas can dissolve in a given volume of cold water than in warm water. 3.) Presence of other solutes - Ions and other solutes decrease the amount of gas that dissolves in water.

Pleural sac

A double layer of thin, moist tissue that encases each lung Fluid between the layers acts as a lubricant and makes the layers adhere to each other Movements of the chest wall also moves the lung Lungs are inflated by the expansion of the chest wall

List the major gases that make up the air we breathe

Air is composed of about •21% oxygen •78% nitrogen •Roughly 1% carbon dioxide and other gases (Nitrogen gas usually ignored because it is not part of the respiratory process)

Describe the general structure of the vertebrate digestive system

Alimentary canal or gastrointestinal (GI) tract •In humans includes mouth, pharynx, esophagus, stomach, intestines and anus Plus accessory structures •May include salivary glands, liver, gallbladder, and pancreas •Not all are found in all vertebrates

Describe the hormone receptors for the three classes of hormones

Amine and polypeptide hormones are generally water-soluble •Not able to cross plasma membranes •Must use receptors on the cell surface - Elicit fast responses Steroid hormones are lipid-soluble •Diffuse across plasma membranes and access receptors in either the cytosol or nucleus

List and give examples of the three different chemical classes of hormones and describe their structural differences

Amines •Derived from tyrosine or tryptophan •Small, water-soluble Polypeptides •Most hormones •Water soluble Steroid hormones •Cholesterol derivatives •Less soluble in water - require carriers •Lipid soluble

Describe how food moves through regions of the alimentary canal, and explain how each region contributes to the process of digestion and absorption

Anterior end functions primarily in ingestion •Mouth, pharynx (throat), and esophagus Middle portion functions in storage and initial digestion •One or more food storage or digestive organs (crop, gizzard, and stomach) •Upper part of small intestine and associated organs (liver, gallbladder, pancreas) Posterior part functions in final digestion, absorption, and elimination •Remainder of small intestine and large intestine •Undigested material defecated through opening (anus or cloaca)

5 types of blood vessels and their structure/functions

Arteries - Conduct blood away from the heart. Have layers of smooth muscle and connective tissue around smooth endothelium. Arterioles - Constrict to control blood distribution to tissues Capillaries - Gas, nutrient, and waste exchange. Have a single-celled layer of endothelium on a basement membrane. Smallest and narrowest vessels in the body Venules - Small, thin extensions of capillaries. Veins - Conduct blood back to the heart. Thinner and less muscular than arteries. •Veins need help returning blood to the heart (smooth muscle contractions help propel blood, valves inside veins squeezed by skeletal muscles)

Open circulatory system

Arthropods, insects, and some mollusks have this circulatory system Basic components: •Hemolymph (instead of blood), which is a mixture of circulatory fluid and interstitial fluid •Vessels •One or more hearts Vessels open into the animal's body cavity (hemocoel)

Describe the process of filtration in the renal corpuscle

As blood flows through glomerulus, a portion of the plasma leaves capillaries and filters into Bowman's capsule Proteins and blood cells remain in plasma Fluid entering Bowman's capsule is the glomerular filtrate Glomerular Filtration Rate (GFR) is rate of filtrate production •Can be increased or decreased by dilation or constriction of afferent arteriole

Mechanisms of digestion and absorption of lipids: formation of micelles and chylomicrons

Bile salts and phospholipids help form micelles, allowing lipids to diffuse into intestinal cells •Gradually release lipids to diffuse into intestinal epithelium Triglycerides reform inside SER of intestinal cells •Aggregate into chylomicrons •Released by exocytosis to pass into lacteals •Fluid from lacteals eventually empties into blood circulation

Uric acid

Birds, insects, and most reptiles Least toxic form of nitrogenous waste More energetically costly to make from ammonia than urea •Balanced against water conserved by excreting semisolid, partly dried precipitate Low amount of water required for excretion

Closed circulatory system

Blood (circulatory fluid) remains within vessels for distribution •Arteries carry blood away from heart, veins bring it back, capillaries link arteries and veins Blood and interstitial fluid are physically separated •Differ in components and chemical composition Found in earthworms, cephalopods, and all vertebrates •Some animals have a closed circulatory system composed of a single circuit •Others have double circulation

Pressure changes in the capillary

Blood enters capillary under pressure •Pressure forces some fluid out of the blood (but not red blood cells or large proteins) Most of the fluid that leaves is recaptured at the venule end of the capillary Lymphatic system will collect fluid that is not captured and return it to the blood

Outline the flow of blood through the heart and blood vessels

Blood enters from systemic (inferior and superior vena cava) or pulmonary veins into atrium Left ventricle ejects blood into the aorta - branches to arteries that distribute the blood Right ventricle ejects blood into the pulmonary trunk - divides into pulmonary arteries Blood flows through one-way atrioventricular (AV) valves into ventricles and out one-way semilunar valves into systemic (aorta) or pulmonary arteries *The image shows the direction of blood flow through the vessels of a closed circulatory system

Four components of blood and their functions

Blood is the transport medium of animals with closed circulatory systems. Plasma •Water and dissolved substances (including nutrients, oxygen, waste products, hormones, proteins) Cells •Erythrocytes (red blood cells) serve the critical function of transporting oxygen •Leukocytes (white blood cells) are crucial components of the immune system •Platelets are cell fragments that function in formation of blood clots

List the four types of gas exchange organs in animals

Body surface Gills (external and internal) Tracheae Lungs

Mechanisms of digestion and absorption of proteins

Broken down to polypeptide fragments by pepsin in the stomach and by proteases such as trypsin in small intestine Pancreas secretes enzymes as inactive precursors •Activated in small intestine Small intestine enzymes complete digestion of proteins into amino acids Transported into intestinal cells and into blood stream

Explain the importance of enzymes in the processes of the digestion and absorption of carbohydrates, proteins, and lipids

Carbohydrates: - Pancreatic amylase digests polysaccharides to produce maltose - Maltose is broken down by enzymes on the brush border of the small intestine Proteins: - Enzymes in the small intestine complete the digestion of proteins into amino acids Lipids: - Digestion of lipids occurs in the small intestine with the digestive enzyme lipase

What is the cardiac output

Cardiac output = Amount of blood the heart pumps in liters / minute Depends on size of the heart and how often it beats Stroke volume - amount of blood a heart ejects at each beat

Large intestine

Cecum (from which extends the appendix), colon, rectum, and anus Primary function to store and concentrate fecal matter and absorb remaining ions and water Defection occurs when feces expelled through the anus as a result of muscular contraction and relaxation Bacteria in the large intestine produce vitamins and flatus

type 2 diabetes mellitus

Cells of the body lose much of their ability to respond to insulin Associated with obesity

What are essential nutrients

Certain compounds cannot be synthesized from any ingested or stored precursor molecule - so they must be obtained in diet - called essential nutrients Four groups: •Essential amino acids •Essential fatty acids •Vitamins •Minerals

Outline the mechanisms for controlling blood flow

Change in arteriolar resistance is a major mechanism to control blood flow to a region - radius is the most important factor Vasodilation - increase in radius of an artery. Leads to increased blood flow, decreased blood pressure. Vasoconstriction - decrease in radius of an artery. Leads to decreased blood flow, increased blood pressure. Controlled by locally produced substances, hormones, and nervous system input

List and define the four terms used to categorize organisms based on their source of heat and ability to maintain body temperature

Classify animals according to •Source of heat - internal or environmental (endotherms generate their own heat, and exotherms body temperature changes with the environment) •Ability to maintain body temperature - fluctuating (heterotherms) or stable (homeotherms) Endothermic homeotherms - birds and mammals Ectothermic heterotherms - other vertebrates and most invertebrates

Circulatory system

Consists of the heart and blood vessels Primary function of a circulatory system is to transport •Necessary materials to the cells of an animal's body •Waste products away from the cells to be released into the environment Two basic types: •Open circulatory system •Closed circulatory system

What is the renal tubule?

Continuous with Bowman's capsule Epithelial cells differ in structure and function along length •Proximal tubule - Drains Bowman's capsule •Loop of Henle - Descending and ascending limbs •Distal tubule Then into collecting duct Peritubular capillaries in cortex and vasa recta capillaries in medulla •Return reabsorbed solutes and water to bloodstream

function and structure of the excretory system

Critical for removing waste from body fluids and maintaining homeostasis Excretory system includes all of an animals organ's that function to remove soluble wastes generated from metabolism •Gills, lungs, kidneys, body surface (in some animals) Animals make use of one or more organs to remove metabolic wastes, excess water and ions, and toxins Most excretory organs contain tubular structures lined with epithelial cells that have the capacity to actively transport ions

Describe the species differences in the oxygen-hemoglobin dissociation curve

Curve can shift between species with different metabolic rates. Smaller animals unload hemoglobin more readily at any given temperature

Describe shifts in the oxygen-hemoglobin dissociation curve

Curve can shift in response to metabolic waste products: Increasing amounts of CO2+, H+, and high temperature make oxygen load and unload easier

Cardiac cycle

Events that produce a single heartbeat Two phases •Diastole -ventricles fill (blood pressure lowest) and atria contract •Systole - ventricles contract and blood is ejected from the heart (blood pressure highest) Heart valves open and shut in response to pressure gradients

Respiratory pigments

Examples of respiratory pigments are hemoglobin and hemocyanin. Hemoglobin - Iron (Fe2+) •4 protein subunits •Each has a heme unit - contains iron •Single hemoglobin molecule binds up to 4 oxygen molecules Hemocyanin - Copper (Cu2+) •Crustaceans and arachnids have hemocyanin All respiratory pigments have a high affinity for oxygen. The binding of oxygen is noncovalent and reversible.

Pancreas

Exocrine portion •Epithelial cells secrete chemicals into a duct •Contents empty into small intestine for digestion Endocrine portion •Endocrine cells produce polypeptide hormones •Islets of Langerhans: - Alpha cells make glucagon - raises blood glucose - Beta cells make insulin - lowers blood glucose

External gills for gas exchange

External gills vary widely in appearance but all have a large surface area with extensive projections Limitations: •Unprotected and subject to damage •Energy is required to wave gills back and forth •Appearance and motion may attract predators

Features and advantages of a closed circulatory system

Features: - One or more contractile, muscular hearts - Solutes exchanged with environment and body cells - Adjusted to match the animal's metabolic demands - Capacity to heal themselves when wounded (clots) - System grows in size as an animal grows Advantages: Animal can grow larger with more efficient supply (nearly all body cells are within one or two cell widths of a blood vessel) Blood flow can be selectively controlled: •Vasodilation/vasoconstriction select which blood vessels are carrying blood at any given time •Different body parts can be supplied with the precise amount of blood needed at any given moment

Describe the four excretory processes

Filtration •An organ acts like a sieve or filter to remove water and small solutes from blood while leaving behind blood cells and large solutes •Material that passes through filter and enters excretory organ is filtrate Reabsorption •Material in filtrate is recaptured and returned to blood Secretion •Some solutes actively transported from the interstitial fluid surrounding the epithelial cells of the tubules into their lumens Excretion •Wastes are excreted as urine

Double circulation

Found in crocodiles, birds and mammals. Double circulation has two atria and two ventricles. Oxygenated and deoxygenated blood separates into two distinct circuits: Pulmonary and systemic circulation Pulmonary circulation •Receives deoxygenated blood from right ventricle •Delivers blood to lungs Systemic circulation - to the body •Receives oxygenated blood from left ventricle •Delivers blood to body - The major advantage of double circulation is two different blood pressures in two different systems - The right ventricle can pump blood through pulmonary circuit with low pressure - At the same time, the left ventricle generates higher pressure into the systemic circulation

General structural and functional features of the kidney

Found in vertebrates and contain specialized tubules of epithelial cells Function to •Promote active transport of sodium, potassium, and other ions to maintain salt and water homeostasis •Eliminate nitrogenous wastes Processes can be controlled by actions of nerves and hormones Most are filtration kidneys •Exception - secretory kidneys in some marine fish Filtration is controlled by mechanical forces •Blood entering the capillaries exerts hydrostatic pressure

Describe the structure and function of a nephron

Functional unit of the kidney Only a single cell thick As many as several million in each kidney Filtering process begins at renal corpuscle •Forms filtrate free of cells and proteins Filtrate passes through three regions of nephron •Substances are reabsorbed or secreted into it When filtrate reaches renal pelvis, it is called urine From the renal pelvis, flows into the urinary bladder

What is the renal corpuscle?

Glomerulus + Bowman's capsule = renal corpuscle Glomerulus •Cluster of interconnected, fenestrated capillaries •Supplied by afferent arteriole •Drained by efferent arteriole •Cells called podocytes encase the capillaries and form filtration slits - thought to prevent proteins from entering filtrate Glomerulus protrudes into Bowman's capsule, a fluid-filled space

List the hormones produced by the pancreas and provide a brief description of the major metabolic functions of each

Glucagon - produced by alpha cells in the Islets of Langerhans. Glucagon raises blood glucose. Insulin - produced by beta cells in the Islets of Langerhans. Insulin lowers blood glucose and is responsible for maintaining normal blood concentrations of glucose, fats, and amino acids.

Describe the dietary categories for animals

Herbivores - eat only plants - Digestive systems contain microorganisms that help digest cellulose Carnivores - consume animal flesh or fluids Omnivores - eat both plant and animal material

Define a hormone and an endocrine gland

Hormones are chemical signals produced by cells in the body •Circulate in the bloodstream •Act on one or more target tissues to alter their functions •Often produced in response to homeostatic challenge Endocrine glands - specialized glands that function in hormone synthesis and secretion •All endocrine glands and other organs with hormone-secreting cells comprise the endocrine system

Name three major hormones important for the regulation of digestion in vertebrates and describe the role of each

Hormones are secreted mainly by cells scattered throughout the epithelium of stomach and small intestine Gastrin released in response to presence of chime. Gastrin stimulates smooth muscle contraction in stomach Pancreas and gallbladder stimulated by cholecystokinin (CCK) and secretin •CCK and secretin stimulate the secretion of digestive enzymes and bicarbonate ions

type 1 diabetes mellitus

Immune system has mistakenly destroyed insulin-producing cells Glucose accumulates to high level in blood Treated by administration of insulin

Mechanisms of digestion and absorption of carbohydrates

In typical omnivore, most carbohydrates are polysaccharides (starch and cellulose from plants and glycogen from animals), some monosaccharides and disaccharides. Digestion: •Some polysaccharide digestion occurs in mouth, but most takes place in small intestine by pancreatic amylase, producing maltose •Maltose and other disaccharides broken down by enzymes on brush border of small intestine •Monosaccharides transported across intestinal epithelium into the blood

Minerals

Inorganic ions Various functions •Cofactors or constituents of enzymes and other proteins •Bone, muscle, nervous system function •Contribute to changes in electrical differences across plasma membranes Many required in trace amounts Examples of minerals: calcium, chlorine, iron

Internal gills for gas exchange

Internal gills are fish gills covered by the operculum Gill arches - main support structure Filaments branch off of gill arches Lamellae branch off of filaments Blood vessels run the length of the filaments •Oxygen-poor blood travels through afferent vessel •Oxygen-rich blood travels through efferent vessel Countercurrent exchange of water and blood flow maximizes oxygen diffusion into blood

Lungs for gas exchange

Internal paired structures •Receive deoxygenated blood from the heart •Return oxygenated blood to the heart Use negative pressure filling •Boyle's Law - pressure and volume are inversely related •Expanding and compressing lungs creates pressure gradients to move the air

Why is extracellular digestion more common than intracellular

Intracellular digestion cannot meet the metabolic demands of an active animal for long, and it has no mechanism for storing food. Extracellular digestion offers protection from hydrolytic enzymes and it occurs more slowly so it can meet the metabolic demands of an animal.

Body surfaces for gas exchange

Invertebrates with one or a few cell layers can use diffusion for gas exchange Some do not even need specialized transport mechanisms Some large, complex animal body surfaces may be permeable to gases •Amphibians are the only vertebrates to rely on their skin for gas exchange underwater

Describe the cellular locations and characteristics of receptors for water soluble hormones

Located on the plasma membrane •Amine and protein/peptide hormones (except thyroid hormone) Only cells with the proper receptors can respond to a hormone Hormone interacts noncovalently and reversibly with the receptor •Prevents cell from being permanently stimulated Binding initiates intracellular signaling pathways involving second messengers Three major signaling pathways (cyclic AMP, diacylglycerol and inositol triphosphate, and receptor tyrosine kinases) •Rapid (occurring in seconds) and involve changing enzyme activity

Structure of the mammalian lungs

Lungs are an internal paired structure that receives deoxygenated blood from the heart and returns oxygenated blood to the heart. Lungs use negative pressure filling. The expanding and compressing of the lungs create pressure gradients to move air. The trachea, which is the tube that leads to the lungs, branches into two bronchi. The bronchioles in the lungs contain alveoli, which are the site of gas exchange. Alveoli are once cell thick: Type I cells are where gas diffuse across, and type II cells are the secretory cells.

Outline the process of ventilation in mammalian lungs

Mammals breathe by tidal ventilation: •Inhalation - intercostals contract to move chest wall up and out, diaphragm contracts and drops down - enlarging thoracic cavity •Exhalation - intercostals and diaphragm relax - compressing thoracic cavity Tidal volume - volume of air normally breathed in and out at rest (approximately 0.5Liter) Lungs can be deflated or inflated further, but they can never completely deflate •Held open by adherence to chest wall •Newborn mammal takes first breath - the only time the lungs are ever completely empty of air

Metabolism/metabolic rate

Metabolism refers to all the bodily activities and chemical reactions in an organism that maintains life Metabolic rate - amount of energy used during a given period of time to power metabolic requirements Basal metabolic rate (BMR) - metabolic cost of living Metabolism and body temperature are closely related •The greater the metabolic rate, the more heat generated Factors impacting metabolic rate: 1.) Altered skeletal muscle activity 2.) Digesting food (food-induced thermogenesis) •Greatest effect from ingested protein 3.) Body mass •Mass-specific BMR - amount of energy expended per gram of body mass in the resting condition - exponential curve •Smaller animals lose heat rapidly - so higher BMR •Does not explain the same relationship in ectotherms Indirect calorimetry: usual method for measuring metabolic rate. Rate at which a resting animal uses oxygen provides a good estimate of BMR

Effect of temperature on an animals internal body

Most animals can only survive a narrow range of temperatures Chemical reactions depend on temperature •Rate increases with increase in body temperature •Enzymes have optimal temperature Proteins can become denatured at high temperatures Heat alters structures of plasma and intracellular membranes •Low temperatures cause membranes to become less fluid, more rigid •High temperatures can cause membranes to become leaky

Mechanisms of digestion and absorption of lipids

Most lipids ingested as triglycerides Digestion occurs almost entirely in small intestine: •Major digestive enzyme, lipase, secreted by pancreas •Triglyceride -> 2 free fatty acids + 1 monoglyceride Emulsification: •Increases surface area, providing greater exposure to lipase •Muscular contractions break up large droplets of lipids •Phospholipids and bile salts prevent small lipid droplets from coalescing

Disadvantages of endothermy

Must consume larger amounts of food to provide nutrients used by cells in formation of ATP Run the risk of overheating (hyperthermia) during intense activity, even in cold weather Endotherms often restricted to environments where water is plentiful

Small intestine

Nearly all digestion of food, and absorption of food and water occurs here Hydrolytic enzymes found on apical surface of epithelial cells or secreted by pancreas into lumen of small intestine Products of digestion absorbed across epithelial cells and enter blood •Vitamins, mineral and water also absorbed

Explain how the nervous system controls different features of the digestive process

Nervous system effects •Local control of muscular and glandular activity by neurons in alimentary canal (signals up and down the canal move digestion along) •Long-distance regulation by the brain (response to stimuli such as stress or sight and smell of food)

List the major components of the mammalian respiratory system

Nose and mouth •Air is warmed and humidified •Mucus and hairs in the nose cleans the air of dust Pharynx - common passageway for air & food Larynx •Vocal cords Trachea - tube that leads to the lungs Lungs

Describe the characteristics of gas transport in blood

Not enough oxygen would dissolve directly into blood to support metabolic needs, so respiratory pigments are used to increase the amount of gas carried in a solution. •Respiratory pigments: proteins that have one or more metal ions and may be contained within red blood cells or plasma

Distinguish between passive and active absorption of food

Nutrients must be absorbed by the epithelial cells lining alimentary canal Three ways: •Simple diffusion (passive) •Facilitated diffusion (passive) •Active transport (active) Alimentary canal cells use some nutrients for their own needs but most transported into blood for the rest of the body

Extracellular digestion

Occurs in most animals and takes place in a cavity that protects interior of cells from hydrolytic enzymes Allows consumption of large food items •Food enters digestive cavity •Food is slowly digested •Absorption of nutrients occurs over a long period of time

Describe the ways in which carbon dioxide is carried in blood

Only a limited amount of CO2+ dissolves in the blood. Some CO2+ is carried by hemoglobin, but most CO2+ is carried as highly soluble bicarbonate ions (HCO3-)

open vs closed circulatory system

Open: the hemolymph is not enclosed in the vessels and is pumped into the body cavity called the hemocoel Closed: the blood is pumped through the vessels separate from the interstitial fluid of the body

List the major categories of nutrients consumed by animals and describe some of their general functions

Organic nutrients are used for two general purposes: - To provide energy - for synthesis of ATP - To make new molecules Carbohydrates: Energy source; component of some proteins; source of carbon Proteins: Provide amino acids to make new proteins; build muscle; some amino acids used as energy source Lipids: Major component of cell membranes; energy source; thermal insulator; building blocks of some hormones Nucleic acids: Provide sugars, bases and phosphates that can be used to make DNA, RNA, and ATP Vitamins: Various functions, some include acting as a coenzyme and antioxidant Inorganic nutrients: Water Minerals

List some of the major endocrine glands found in animals and the hormones they secrete

Pancreas: insulin Ovaries: estrogen Testes: androgens Thyroid: thyroid hormone Pineal gland: melatonin

Pharynx and esophagus

Pathway to storage organs Do not contribute to digestion or absorption Swallowing begins in pharynx as voluntary action •Continues in esophagus by involuntary peristalsis

Components of a centrifugal blood sample

Plasma •Top layer of the centrifugal blood sample •Typically about half of total volume of blood Leukocytes •Make up narrow white layer below plasma Erythrocytes •The bottom visible layer of the centrifugal blood sample •The volume of blood composed of erythrocytes is called the hematocrit, which ranges between 35% and 65% in vertebrates

What are nitrogenous wastes

Produced when proteins and nucleic acids are broken down and metabolized Molecules include nitrogen from amino groups (−NH2) Toxic at high concentrations 3 main forms of nitrogenous waste: ammonia, urea, uric acid

Pros and cons of open circulation

Pros: - Nutrients and waste exchange by diffusion between hemolymph and body cells - Metabolically inexpensive - As an animal's activity increases, circulation becomes more efficient Cons: - Hemolymph cannot be selectively delivered to different tissues

Describe the process of hormone synthesis

Protein and polypeptide hormones are synthesized and secreted at a steady rate or in a circadian rhythm in an unstimulated cell •Changing transcription rates increases or decreases the supply •Reservoir of stored hormone in secretory vesicles Steroid hormones are made on demand with no significant storage

Identify several invertebrate osmoregulatory organs involved in the process of elimination

Protonephridia, metanephridia, and malpighian tubules

Compare and contrast the process of elimination in each osmoregulatory invertebrate elimination organ

Protonephridia: - A series of branching tubules uses the beating of ciliated cells to filter fluids from the body cavity. As fluid travels through the tubule, solutes are reabsorbed. Excess water and wastes empty through openings in body wall called nephridiopores. Metanephridia: - The nephrostome collects coelomic fluid containing nitrogenous wastes. The fluid moves through the tubule where solutes are reabsorbed. The nitrogenous wastes are excreted through nephridiopores in body wall. Malpighian tubules: - Cells lining the malphighian tubules actively transport ions and uric acid from hemolymph to lumen. This creates an osmotic gradient drawing water and solutes into tubule. The fluid moves into the hindgut where water and solutes are reabsorbed. Nitrogenous wastes are excreted together with feces through anus.

Identify the four main mechanisms animals use to exchange heat with the environment

Radiation •Emission of electromagnetic waves by the surfaces of objects •Rate determined by temperature of radiating surface Evaporation •Whenever water vaporizes from the body's surface, the heat required to drive the process is conducted from the surface, thereby cooling the animal Convection •Transfer of heat by the movement of air or fluid next to the body •Sitting near fans, bat flapping wings, or elephant waving ears Conduction •Body surface loses or gains heat through direct contact with cooler or warmer substances •Water has a higher specific heat than air

Describe the cellular location and characteristics of receptors for lipid-soluble hormones

Receptors located within the cell (in cytosol or nucleus) Steroid hormone-receptor complex is a transcriptional activator for particular genes, increasing the amount of gene product One hormone can exert a variety of actions throughout the body •Can influence a number of genes within a single cell or in different cells

Electrocardiogram

Record of electrical impulses generated during the cardiac cycle by monitoring the electrical activity produced by the SA node P wave - begins when SA node generates action potentials QRS complex - complex wave- AV node excites ventricles (ventricular depolarization) T wave - repolarization of ventricles back to resting state

Describe the process of negative pressure filling of the lungs

Reptiles, birds, and mammals use negative pressure filling Volume of lung expands, creating negative pressure, and air is drawn into lungs Mammals use tidal ventilation: •Inhalation - intercostals contract to move chest wall up and out, diaphragm contracts and drops down - enlarging thoracic cavity •Exhalation - intercostals and diaphragm relax - compressing thoracic cavity

Describe the role of respiratory centers and chemoreceptors in the regulation of ventilation

Respiratory centers: several nuclei in the brainstem of vertebrates that initiates the expansion of the lungs Chemoreceptors: chemoreceptors monitor blood gases and are located in the aorta, carotid arteries, and the brainstem. - Chemoreceptors monitor hydrogen ions (pH), the pressure of O2, and the pressure of CO2 - Chemoreceptors increase the breathing rate if oxygen levels fall or if pH drops due to increased acid production from anaerobic metabolism or increased carbon dioxide from aerobic metabolism

Insulin

Responsible for maintaining normal blood concentrations of glucose, fats, and amino acids Acts on plasma membrane receptors to facilitate transport of glucose into cytosol •Involves actions of glucose transporters (GLUTs) in cytosolic membrane-bound vesicles •Insulin stimulates fusion of vesicles with plasma membrane •When insulin concentration decreases, GLUTs return to vesicles in the cytosol Also stimulates transport of amino acids and promotes fat deposition

Outline how microorganisms can help digest cellulose in the specialized stomach of ruminants and other herbivores

Ruminants (sheep, goats, llamas, cows) can digest cellulose with the help of microorganisms living in digestive tract. - Lack the enzymes needed to digest cellulose Ruminants have 3 outpouches of the lower esophagus: •Rumen and reticulum - contain cellulose-digesting microbes •Omasum - absorbs some of the water and ions from cud Eventually partially digested food, microbes, and by-products of microbial digestion reach the abomasum (true stomach) •Contains acid and proteases

The stomach

Saclike organ evolved for storing food •Muscular nature helps break up food •Partially digests proteins •Regulates rate of emptying into small intestine Glands in the stomach secrete: •Hydrochloric acid - kills microbes, dissolves particulate matter •Pepsinogen - converted to pepsin to begin protein digestion Epithelium coated with alkaline mucus No lipid or carbohydrate digestion occurs in the stomach

Describe the structure of the GI tract

Same general structure from the midpoint of the esophagus to the anus or cloaca •Lumen lined by epithelial and glandular cells •Secretory cells release a protective layer of mucus •Other cells release hormones •Glands release acid, enzymes, water, and ions The epithelial cells are linked by tight junctions and surrounded by layers of tissue made of smooth muscles, neurons, connective tissue, and blood vessels •Neurons activated by sight and smell of food, presence of food in tract

Leptin

Secreted by adipose tissue to regulate appetite •Released in proportion to amount of adipose tissue in the body •Acts on hypothalamus to inhibit appetite and increase metabolic rate •Decreasing adipose tissue decreases leptin - thus increasing appetite

Pancreas function

Secretes digestive enzymes and bicarbonate ion-rich fluid into the duodenum Bicarbonate neutralizes chyme as it enters small intestine

Alimentary canal

Single elongated tube with an opening at both ends. Contains smooth muscle Lined by epithelial cells •Synthesize and secrete digestive enzymes •Secrete hormones •Transport digested material Several specialized regions •Different environments for different processes •Storage area

Liver function

Site of bile production •Bile contains bicarbonate ions (neutralize acids), cholesterol, phospholipids, organic wastes, and bile salts (break up fat droplets)

Describe the surface area specializations of the small intestine

Small intestine specialized to carry out the bulk of digestion and absorption •Mucosal infoldings •Villi - finger-like projections (epithelial cells with microvilli create brush border) Specializations increase surface area 600-fold •Increases likelihood of food particle encountering digestive enzyme and being absorbed

Specialization of the stomach in birds

Stomach of birds divided into two parts •Proventriculus - glandular portion that secretes acid and pepsinogen •Gizzard - grinds food into smaller fragments with the help of sand or tiny stones. Action of a bird's stomach reduces food to chime- solution that contains water, ions, protein fragments, nucleic acids, carbohydrates, fat droplets, other small molecules

The crop

Storage organ - little or no digestion Found in most birds and some invertebrates Size dependent on diet Provides material regurgitated by birds for their young

Gallbladder function

Stores bile and secretes it during a meal People lacking a gallbladder can digest fat, but may need to limit how much is eaten at once