Anatomy Final

Which of the following blood types is a person whose blood cells were agglutinated by both anti-A serum and anti-B serum, but not by anti-Rh serum?

AB negative

What energizes the myosin head?

ATP hydrolysis reaction

During this phase of cell division, the centromeres split leading to separation and subsequent migration of the two members of a chromatid pair to opposite poles of the cells. The cleavage furrow also begins to develop during this phase.

Anaphase

Choose the directional term that would make the following sentence correct. The sternum is _____ to the heart.

Anterior

Which of the following induces the production of a specific antibody?

Antigen

Which of the following cells is NOT an agranular leukocyte?

Basophile

Smooth muscle tone is maintained by the prolonged presence of [_____] in the muscle cell's cytosol?

Calcium ions

Which type of muscle tissue contracts when excited by their own autorhythmic muscle fibers?

Cardiac muscle

Microfilaments, intermediate filaments and microtubules are all components of a cell's ...

Cytoskeleton

_____occurs when an embryonic stem cell becomes a neuron.

Differentiation

Which of the following is the most important method of capillary exchange?

Diffusian

A biconcave disc has a much lesser surface area and an increased distance for the diffusion of gas molecules into and out of the RBC than would, say, a sphere or a cube.

False

A hemoglobin molecule consists of protein called globin composed of four polypeptide chains (two alpha and two beta chains); six ringlike non protein pigments called hem is bound to only two of the four chains.

False

A skeletal muscle as a functional unit or organ, refers to multiple bundles (fascicles) of muscle fibers. The fibers, the bundles and the muscles are surrounded by connective tissue layers. Enclosing each muscle fiber is a layer of connective tissue called the epimysium; enclosing each fascicle is a layer called the endomysium, and enclosing each muscle is a layer of connective tissue known as the perimysium. Independent muscles are separated by a mucous membrane.

False

All RBCs in the male blood contain about 280 million hemoglobin molecules total.

False

Amino acids have a carboxyl group (shaded blue) and an amino group (shaded red). The side chain (R group) is the same in each amino acid.

False

Blood is less viscous than water and feels like water. The temperature of blood is 36°C, about 1°C higher than oral or rectal body temperature, and it has a neutral pH ranging from 7:00 to 7.15 (average = 7.1).

False

Cardiac output is the volume of blood ejected from the left ventricle into the aorta each day.

False

During muscle contraction, myosin is blocked from binding to actin because strands of tropomyosin cover the myosin‐binding sites on actin.

False

Endomysium separate individual muscle fascicles from one another.

False

Erythropoiesis is the production of WBCs.

False

Homeostatic mechanisms maintain the pH of blood between 8:35 and 8.45, which is slightly more basic (alkaline) than pure water.

False

In a connective tissue many cells are tightly packed together with little or no extracellular matrix, whereas in a epithelial tissue a large amount of extracellular material separates cells that are usually widely scattered.

False

Matter exists in three states: solid, liquid and gas. All forms of matter are made up of unlimited number of building blocks called chemical elements.

False

Muscles can pull but they never push.

False

Nutrients are not able to diffuse quickly enough from blood in the chambers of the heart to supply all layers of cells that make up the heart wall. For this reason, the myocardium has its own network of blood vessels, the coronary circulation or cardiac circulation. The coronary arteries branch from the ascending aorta and encircle the heart like a crown encircles the head. While the heart is contracting, blood is squeezed in the coronary arteries because they. When the heart relaxes, the high pressure of blood in the aorta propels blood through the coronary veins, into capillaries, and then into coronary sinus.

False

Ordinarily, the attachment of the muscle tendon to the stationary, distally located bone is called the insertion .

False

Oxygen and carbon dioxide are carried in the hem portion of the hemoglobin.

False

Oxygen and carbon dioxide are carried in the hem portion of the hemoglobin. The only difference is that oxygen is irreversible combined to hem while carbon dioxide in a reversible way.

False

People whose RBCs have Rh antigens are designated Rh− (Rh negative); those who lack Rh antigens are designated Rh+ (Rh positive).

False

Planes are imaginary flat surfaces that pass through the body or its parts. A coronal plane is a vertical plane that divides the body or an organ into a left and right side

False

Planes are imaginary flat surfaces that pass through the body or its parts. A coronal plane is a vertical plane that divides the body or an organ into a superior and inferior part.

False

Planes are imaginary flat surfaces that pass through the body parts. A coronal plane is a vertical plane that divides the body into right and left sides. When such a plane passes through the midline of the body it divides it into equal right and left sides, and it is called a midcoronal plane or a median plane. If the coronal plane does not pass through the midline but instead divides the body into unequal right and left sides, it is called a paracoronal plane

False

Skeletal muscle tissue is so named because most skeletal muscles move the bones of the skeleton. A few skeletal muscles attach to and move the skin or other skeletal muscles. Skeletal muscle tissue is striated: Alternating light and dark protein bands (striations) are seen when the tissue is examined with a microscope. Skeletal muscle tissue works in a involuntary manner. Its activity can't be consciously controlled by neurons (nerve cells) that are part of the somatic (voluntary) division of the nervous system.

False

The ABO blood group is based on two glycolipid antigens called A & B . People whose RBCs display only antigen A have a type B blood.

False

The alternating dark A bands ands light I bands create the striations that can be seen in both myofibrils and in whole skeletal and cardiac muscle fibers. A narrow H zone in the center of each A band contains thin but not thick filaments.

False

The color of blood varies with its oxygen content. When unsaturated with oxygen, it is bright red. When saturated with oxygen, it is dark red.

False

The components of a sarcomere are organized into a variety of bands and zones. The darker middle part of the sarcomere is the I band, which extends the entire length of the thick filaments. Toward each end of the I band is a zone of overlap, where the thick and thin filaments lie side by side. The A band is a lighter, less dense area that contains the rest of the thin filaments but no thick filaments, and a Z disc passes through the center of each A band.

False

The difference in concentration of a specific chemical, like Na+, on the inside and outside of a plasma membrane is referred as a(n) .

False

The heart has four chambers. The superior receiving chambers are the ventricles, and the two inferior pumping chambers are the atria.

False

The left ventricle ejects blood into the pulmonary trunk. The right side of the heart is the pump for systemic circulation; it receives bright red oxygenated blood from the lungs. In systemic tissues, arteries give rise to smaller-diameter arterioles, which finally lead into extensive beds of pulmonary capillaries.

False

The less hydrogen ions are dissolved in the solution more acidic it will be; the less hydroxide ions the more basic (alkaline) will be the solution. A solution acidity or alkalinity is expressed on the pH scale which extend 0 to 14.

False

The major ventral cavities in the trunk are the cranial and spinal (vertebral) cavities.

False

The plasma membrane forms the cell's flexible outer surface, separating the cell's internal environment (everything inside the cell) from the external environment (everything outside the cell). It is a selective barrier that regulates the flow of materials into and out of a cell. This selectivity is based exclusively on the phospholipid bilayer. All the proteins in the plasma membrane are the so called receptors and only play a role in signaling between cells and their external environment.

False

The right ventricle is the thickest chamber of the heart, averaging 10-15 mm, and forms the apex of the heart. Like the left ventricle, the right ventricle contains trabeculae carneae and has chordae tendineae that anchor the cusps of the tricuspid valve to papillary muscles.

False

The sarcolemma action potential propagating into the T-tubule system causes opening of Ca2++ pumps.

False

The structural and molecular formulas for the monosaccharides and the disaccharide. In dehydration synthesis, two smaller molecules are joined to form a larger molecule with a loss of a water molecule. In this image the structural formula of the disaccharide maltose is presented.

False

Together, all the three muscle types of the body compose the skeletomuscular system.

False

Two events that are not seen in mitotic prophase occur during prophase I of meiosis. First, the two sister chromatids of each pair of homologous chromosomes pair off, an event called called crossing-over . The resulting four chromatids form a structure called a triad. Second, parts of the chromatids of two homologous chromosomes may be exchanged with one another. Such an exchange between parts of nonsister (genetically different) chromatids is called synapsis.

False

Two of the important proteins in a sarcomere are myosin, which forms the thin filament, and actin, which forms the thick filament. Myosin has a long, fibrous tail and a globular head, which binds to actin. The myosin head also binds to AMP, which is the source of energy for muscle movement.

False

Unlike meiosis, which is complete after a single round, mitosis occurs in two successive stages: mitosis I and mitosis II. During the interphase that precedes mitosis I, the chromosomes of the diploid cell start to replicate. As a result of replication, each chromosome consists of two sister (genetically identical) chromatids, which are attached at their centromeres. This replication of chromosomes is similar to the one that precedes meiosis in somatic cell division.

False

Upon entering the lumen of a lymphatic capillary, the collected fluid and associated cells (mostly red blood cells) is known as lymph. Each lymphatic capillary carries lymph into an ever larger lymphatic vessels, which are connected to a lymph nodes. Lymph is ultimately returned to the venous circulation so it is considered as blood.

False

Within the nucleus are most of the cell's hereditary units, called genes, which control cellular structure and direct cellular activities. Genes are arranged along chromosomes. Human somatic (body) cells have 46 chromosomes, 23 inherited from each parent and these cells are called haploid cells.

False

Which of the following plasma proteins plays a role in blood clotting?

Fibrogen

A sperm cell is the only type of human cell that contains a _____, which is a whip-like structure that helps propel the sperm towards an oocyte.

Flagellum

Which plane would allow one to view the heart and lungs from a posterior view?

Frontal

Which of the following plasma proteins plays a role in disease resistance?

Globulins

Which of the following is NOT a true statement regarding blood?

Hemocytoblasts are a common component of circulating blood

During muscle contraction by the sliding filament mechanism, thin filaments are pulled towards the ...

M line

Lymphatic Nodules Lymphatic nodules (follicles) are egg-shaped masses of lymphatic tissue that are not surrounded by a capsule. Because they are scattered throughout the lamina propria (connective tissue) of mucous membranes lining the gastrointestinal, urinary, and reproductive tracts and the respiratory airways, lymphatic nodules in these areas are also referred to as mucosa-associated lymphatic tissue or ..........

MALT

Which of the following is NOT considered an organ of the immune system?

MALT

Which of these provides a non-specific second line of defense?

Macrophages

Which of the following is NOT a function of the lymphatic and immune system?

Maintaining water homeostasis in the body

Cross bridges are formed during muscle contraction when _____ of the thick filaments binds to _____ on the thin filaments.

Myosin and actin

Which of the following cells is part of the body's second line of defense?

Natural Killer (NK) cells

Choose the directional term that would make the following sentence correct. The heart is _____ to the liver.

Superior

The stomach is _____ to the urinary bladder.

Superior

The following is a particular sequence of base triplet on a DNA molecule: ATG. What is the corresponding codon for the mRNA?

TAC

Which organ produces a hormone that promotes maturation of T cells?

The thymus gland

The left subclavian vein receives lymph from the .....

Thoracic Duct

Because most plasma proteins are too large to leave blood vessels, interstitial fluid contains only a small amount of protein. Proteins that do leave blood plasma cannot return to the blood by diffusion because the concentration gradient (high level of proteins inside blood capillaries, low level outside) opposes such movement. The proteins can, however, move readily through the more permeable lymphatic capillaries into lymph. Thus, an important function of lymphatic vessels is to return the lost plasma proteins and plasma to the bloodstream

True

Blood can clot (become gel-like), which protects against its excessive loss from the cardiovascular system after an injury. In addition, its white blood cells protect against disease by carrying on phagocytosis. Several types of blood proteins, including antibodies, interferons, and complement, help protect against disease in a variety of ways.

True

Blood flowing through tissue capillaries picks up carbon dioxide, a waste product of metabolism, some of which combines with amino acids in the globin part of hemoglobin. As blood flows through the lungs, the carbon dioxide is released from hemoglobin and then exhaled. Hemoglobin transports about 23% of the total carbon dioxide, the remaining carbon dioxide is dissolved in plasma or carried as bicarbonate ions.

True

Blood is denser and more viscous (thicker) than water and feels slightly sticky. The temperature of blood is 38°C (100.4°F), about 1°C higher than oral or rectal body temperature, and it has a slightly alkaline pH ranging from 7.35 to 7.45 (average = 7.4).

True

Blood passes from the left atrium into the left ventricle through the bicuspid (mitral), which, as its name implies, has two cusps. The term mitral refers to the resemblance of the bicuspid valve to a bishop's hat (miter), which is two-sided. It is also called the left atrioventricular valve.

True

Blood samples for laboratory testing may be obtained in several ways. The most common procedure is venipuncture, withdrawal of blood from a vein using a needle and collecting tube, which contains various additives. A tourniquet is wrapped around the arm above the venipuncture site, which causes blood to accumulate in the vein. This increased blood volume makes the vein stand out. Opening and closing the fist further causes it to stand out, making the venipuncture more successful. A common site for venipuncture is the median cubital vein anterior to the elbow.

True

Blood transports oxygen from the lungs to the cells of the body and carbon dioxide from the body cells to the lungs for exhalation. It carries nutrients from the gastrointestinal tract to body cells and hormones from endocrine glands to other body cells. Blood also transports heat and waste products to various organs for elimination from the body.

True

Cardiac output is the volume of blood ejected from the left or right ventricle into the aorta or pulmonary trunk each minute

True

Cell-mediated immunity is particularly effective against (1) intracellular pathogens, which include any viruses, bacteria, or fungi that are inside cells; (2) some cancer cells; and (3) foreign tissue transplants. Thus, cell-mediated immunity always involves cells attacking cells. Antibody-mediated immunity works mainly against extracellular pathogens, which include any viruses, bacteria, or fungi that are in body fluids outside cells. Since antibody-mediated immunity involves antibodies that bind to antigens in body humors or fluids (such as blood and lymph), it is also referred to as humoral immunity.

True

Change of the name of fluid according the sequence of fluid flow: blood capillaries (blood plasma) → interstitial spaces (interstitial fluid) → lymphatic capillaries (lymph) → lymphatic vessels (lymph) → lymphatic trunks or ducts (lymph) → junction of the internal jugular and subclavian veins (blood plasma).

True

Circulating blood helps maintain homeostasis of all body fluids. Blood helps regulate pH through the use of buffers. It also helps adjust body temperature through the heat-absorbing and coolant properties of the water in blood plasma and its variable rate of flow through the skin, where excess heat can be lost from the blood to the environment. In addition, blood osmotic pressure influences the water content of cells, mainly through interactions of dissolved ions and proteins.

True

Connective tissue surrounds and protects muscular tissue. The subcutaneous layer or hypodermis, which separates muscle from skin, is composed of areolar connective tissue and adipose tissue. It provides a pathway for nerves, blood vessels, and lymphatic vessels to enter and exit muscles. The adipose tissue of the subcutaneous layer stores most of the body's triglycerides, serves as an insulating layer that reduces heat loss, and protects muscles from physical trauma.

True

Contractility is the ability of muscular tissue to shorten forcefully when stimulated by an action potential. When a skeletal muscle contracts, it generates tension (force of contraction) while pulling on its attachment points. If the tension generated is great enough to overcome the resistance of the object to be moved, the muscle shortens and movement occurs, the muscle performed work.

True

Cytoplasm—all the cellular contents within the plasma membrane except for the nucleus—consists of cytosol and organelles. Cytosol is the fluid portion of cytoplasm, containing water, ions, glucose, amino acids, fatty acids, proteins, lipids, ATP, and waste products. It is the site of many chemical reactions required for a cell's existence. Organelles are specialized structures with characteristic shapes that have specific functions.

True

Cytotoxic T cells attack some tumor cells and transplanted tissue cells, as well as cells infected by microbes.

True

Descriptions of any region or part of the human body assume that it is in a standard position of reference called the anatomical position. In the anatomical position, the subject stands erect facing the observer, with the head level and the eyes facing directly forward. The lower limbs are parallel and the feet are flat on the floor and directed forward, and the upper limbs are at the sides with the palms turned forward.

True

Direct pressure from the outside of the neck onto the carotid sinuses should stimulate the carotid sinus reflex and slow the heart rate and lower blood pressure.

True

During hemopoiesis, some of the myeloid stem cells differentiate into progenitor cells. Other myeloid stem cells and the lymphoid stem cells develop directly into precursor cells. Progenitor cells are no longer capable of reproducing themselves and are committed to giving rise to more specific elements of blood. Some progenitor cells are known as colony-forming units. Progenitor cells, like stem cells, resemble lymphocytes and cannot be distinguished by their microscopic appearance alone

True

Each RBC contains about 280 million hemoglobin molecules.

True

Each chromosome is a long molecule of DNA that is coiled together with several proteins. When coiling is complete, two identical DNA molecules and their histones form a pair of chromatids, which are held together by a centromere.

True

Endomysium penetrates the interior of each fascicle and separates individual muscle fibers from one another. The endomysium is mostly reticular fibers. Perimysium is also a layer of dense irregular connective tissue, but it surrounds groups of 10 to 100 or more muscle fibers, separating them into bundles called fascicles. Many fascicles are large enough to be seen with the naked eye. They give a cut of meat its characteristic "grain"; if you tear a piece of meat, it rips apart along the fascicles. Epimysium is the outer layer, encircling the entire muscle. It consists of dense irregular connective tissue.

True

Entire microbes or parts of microbes may act as antigens. Chemical components of bacterial structures such as flagella, capsules, and cell walls are antigenic, as are bacterial toxins. Nonmicrobial examples of antigens include chemical components of pollen, egg white, incompatible blood cells, and transplanted tissues and organs. Typically, just certain small parts of a large antigen molecule act as the triggers for immune responses. These small parts are called epitopes. Most antigens have many epitopes, each of which induces production of a specific antibody or activates a specific T cell.

True

Fascia is a dense sheet or broad band of irregular connective tissue that supports and surrounds muscles and other organs of the body. Fascia holds muscles with similar functions together. Fascia allows free movement of muscles; carries nerves, blood vessels, and lymphatic vessels; and fills spaces between muscles

True

Fast glycolytic (FG) fibers have low myoglobin content, relatively few blood capillaries, and few mitochondria, and appear white in color. They contain large amounts of glycogen and generate ATP mainly by glycolysis. Due to their ability to hydrolyze ATP rapidly, FG fibers contract strongly and quickly. These fast‐twitch fibers are adapted for intense anaerobic movements of short duration, such as weight lifting or throwing a ball, but they fatigue quickly.

True

Helper T cells aid the immune responses of both cell-mediated and antibody-mediated immunity.

True

Huxley was the first to suggest the sliding filament theory in 1953. The novel theory directly introduced a new concept called cross-bridge theory which explains the molecular mechanism of sliding filament. Cross-bridge theory states that actin and myosin form a protein complex by attachment of myosin head on the actin filament, thereby forming a sort of cross-bridge between the two filaments. The sliding filament theory is a universally accepted explanation of the mechanism that underlies muscle contraction

True

Huxley was the first to suggest the sliding filament theory in 1953. The novel theory directly introduced a new concept called cross-bridge theory which explains the molecular mechanism of sliding filament. Cross-bridge theory states that actin and myosin form a protein complex by attachment of myosin head on the actin filament, thereby forming a sort of cross-bridge between the two filaments. The sliding filament theory is a universally accepted explanation of the mechanism that underlies muscle contraction.

True

Immunity or resistance is the ability to ward off damage or disease through our defenses. Vulnerability or lack of resistance is termed susceptibility. The two general types of immunity are (1) innate and (2) adaptive. Innate (nonspecific) immunity refers to defenses that are present at birth. Innate immunity does not involve specific recognition of a microbe and acts against all microbes in the same way.

True

In addition to cardiac muscle tissue, the heart wall also contains dense connective tissue that forms the fibrous skeleton of the heart. Essentially, the fibrous skeleton consists of four dense connective tissue rings that surround the valves of the heart, fuse with one another, and merge with the interventricular septum. In addition to forming a structural foundation for the heart valves, the fibrous skeleton prevents overstretching of the valves as blood passes through them. It also serves as a point of insertion for bundles of cardiac muscle fibers and acts as an electrical insulator between the atria and ventricles.

True

In an isometric contraction, the tension generated is not enough to exceed the resistance of the object to be moved, and the muscle does not change its length. An example would be holding a book steady using an outstretched arm.

True

In antibody-mediated immunity, B cells transform into plasma cells, which synthesize and secrete specific proteins called antibodies (Abs) or immunoglobulins (Igs). A given antibody can bind to and inactivate a specific antigen.

True

In cells that are not dividing, the chromatin appears as a diffuse, granular mass. Electron micrographs reveal that chromatin has a beads-on-a-string structure. Each bead is a nucleosome that consists of double-stranded DNA wrapped twice around a core of eight proteins called histones, which help organize the coiling and folding of DNA. The string between the beads is called linker DNA, which holds adjacent nucleosomes together.

True

In contrast to skeletal muscle, cardiac muscle produces little of the ATP it needs by anaerobic cellular respiration. Instead, it relies almost exclusively on aerobic cellular respiration in its numerous mitochondria. Cardiac muscle fibers use several fuels to power mitochondrial ATP production. In a person at rest, the heart's ATP comes mainly from oxidation of fatty acids (60%) and glucose (35%), with smaller contributions from lactic acid, amino acids, and ketone bodies. During exercise, the heart's use of lactic acid, produced by actively contracting skeletal muscles, rises

True

In muscle, the refractory period is the time interval during which a second contraction cannot be triggered. The refractory period of a cardiac muscle fiber lasts longer than the contraction itself. As a result, another contraction cannot begin until relaxation is well under way. For this reason, tetanus (maintained contraction) cannot occur in cardiac muscle as it can in skeletal muscle.

True

In producing movement, bones act as levers, and joints function as fulcrum of these levers while muscles act as the force.

True

In relaxed muscle, myosin is blocked from binding to actin because strands of tropomyosin cover the myosin‐binding sites on actin. The tropomyosin strands in turn are held in place by troponin molecules. When calcium ions (Ca2+) bind to troponin, troponin undergoes a conformational change (change in shape); this change moves tropomyosin away from myosin‐binding sites on actin, and muscle contraction subsequently begins as myosin binds to actin.

True

In standard shorthand chemist write formulas of organic molecules, carbon atoms are understood to be at locations where two bond lines intersect, and single hydrogen atoms are not indicated.

True

In the Watson-Crick double helix model, DNA resembles a spiral ladder. Two strands of alternating phosphate groups and deoxyribose sugars form the uprights of the ladder. Paired bases, held together by hydrogen bonds, form the rungs.

True

In the neck, the thoracic duct also receives lymph from the left jugular and left subclavian trunks before opening into the anterior surface of the junction of the left internal jugular and subclavian veins. The left broncho mediastinal trunk joins the anterior surface of the subclavian vein independently and does not join the thoracic duct. As a result, all the lymph form the left upper side of the body and the entire body below the diaphragm returns to the superior vena cava via the left brachiocephalic vein.

True

In the process of translation, the nucleotide sequence in an mRNA molecule specifies the amino acid sequence of a protein. Ribosomes in the cytoplasm carry out translation.

True

In the synthesis of phospholipids, two fatty acids attach to the first two carbons of the glycerol backbone and a phosphate group links a small charged group to the third carbon in glycerol. The circle represents the polar head region, and the two wavy lines represent the two nonpolar tails. Double bonds in the fatty acid hydrocarbon chain often form kinks in the tail.

True

Inflammation is a nonspecific, defensive response of the body to tissue damage. Inflammation is an attempt to dispose of microbes, toxins, or foreign material at the site of injury, to prevent their spread to other tissues, and to prepare the site for tissue repair in an attempt to restore tissue homeostasis. The five classical signs of inflammation are heat, pain, redness, swelling, and loss of function (Latin: calor, dolor, rubor, tumor, and functio laesa).

True

Inflammation is a process by which the body's white blood cells and substances they produce protect us from infection with foreign organisms, such as bacteria and viruses. The phagocytosis is a nonspecific immune response, meaning that the phagocytes attack any foreign bodies.

True

Intercalated discs are unique to cardiac muscle fibers. These microscopic structures are irregular transverse thickenings of the sarcolemma that connect the ends of neighboring processes of cardiac muscle cells to one another thus forming a cardiac muscle fiber. The discs contain desmosomes, which hold the fibers together, and gap junctions, which allow muscle action potentials to spread from one cardiac muscle fiber to another and function as a syncytium.

True

Isometric contractions are important for maintaining posture and for supporting objects in a fixed position

True

Like cardiac muscle tissue, smooth muscle tissue is usually activated involuntarily. Of the two types of smooth muscle tissue, the more common type is visceral (single‐unit) smooth muscle tissue. It is found in the skin and in the walls of small arteries and veins and of hollow organs such as the stomach, intestines, uterus, and urinary bladder.

True

Like cardiac muscle, smooth muscle is usually activated involuntarily.

True

Located along lymphatic vessels are about 600 bean-shaped lymph nodes.

True

Located in the plasma membrane of body cells are "self-antigens," the major histocompatibility complex (MHC) antigens. Thousands to several hundred thousands MHC molecules mark the surface of each of our body cells except red blood cells, their normal function is to help T cells recognize that an antigen is foreign, not self. Such recognition is an important first step in any adaptive immune response. The two types of major histocompatibility complex antigens are class I and class II. Unless in identical twins, MHC antigens are unique to each individual

True

Lymph flows through a lymph node in one direction only. It enters through several afferent lymphatic vessels, which penetrate the convex surface of the node at several points. The afferent vessels contain valves that open toward the center of the node, directing the lymph inward. Within the node, lymph enters sinuses, a series of irregular channels that contain branching reticular fibers, lymphocytes, and macrophages and drain into one or two efferent lymphatic vessels, which are wider and fewer in number than afferent vessels. They contain valves that open away from the center of the lymph node to convey lymph out of the node. Efferent lymphatic vessels emerge from one side of the lymph node at a slight depression called a hilum. Blood vessels also enter and leave the node at the hilum.

True

Lymph nodes, like the thymus, are covered by a capsule of dense connective tissue that extends into the node. The capsular extensions, called trabeculae, divide the node into compartments, provide support, and route for blood vessels into the interior of a node. Internal to the capsule is a supporting network of reticular fibers and fibroblasts. The capsule, trabeculae, reticular fibers, and fibroblasts constitute the stroma of a lymph node

True

Lymphatic capillaries are slightly larger in diameter than blood capillaries and have a unique one-way structure that permits interstitial fluid to flow into them but not out. The ends of endothelial cells that make up the wall of a lymphatic capillary overlap. When pressure is greater in the interstitial fluid than in lymph, the cells separate slightly, like the opening of a one-way swinging door, and interstitial fluid enters the lymphatic capillary. When pressure is greater inside the lymphatic capillary, the cells adhere more closely, and lymph cannot escape back into interstitial fluid. The pressure is relieved as lymph moves further down the lymphatic capillary

True

Lymphatic capillaries are tiny, thin-walled micro vessels located in the spaces between cells (except in the central nervous system and non-vascular tissues) which serve to drain and process extracellular fluid. Upon entering the lumen of a lymphatic capillary, the collected fluid and associated cells (notably white blood cells) is known as lymph. Each lymphatic capillary carries lymph into an ever larger lymphatic vessel, which in turn connects to a lymph nodes. Lymph is ultimately returned to the venous circulation.

True

Lymphatic vessels begin as lymphatic capillaries. These capillaries, which are located in the spaces between cells and blood capillaries, are closed at their beginnings. Just as blood capillaries converge to form venules and then veins, lymphatic capillaries unite to form larger lymphatic vessels, which resemble small veins in structure but have thinner walls and more valves. At intervals along the lymphatic vessels, lymph flows through lymph nodes, encapsulated bean-shaped organs consisting of masses of B cells and T cells. Tissues that lack lymphatic capillaries include avascular tissues (such as cartilage, the epidermis, and the cornea of the eye), portions of the spleen, red bone marrow and the central nervous system

True

Matter exists in three states: solid, liquid and gas. All forms of matter are made up of limited number of building blocks called chemical elements. Scientists now recognize 118 elements. Each element is designated by a chemical symbol, one or two letters of the elements name.

True

Most components of blood plasma, such as nutrients, gases, and hormones, filter freely through the blood capillary walls to form interstitial fluid, but more fluid filters out of blood capillaries than returns to them by reabsorption. The excess filtered fluid—about 3 liters per day in the whole body—drains into lymphatic vessels and becomes lymph.

True

Most parts of the body receive blood from branches of more than one artery, and where two or more arteries supply the same region, they usually connect. These connections, called anastomoses, provide alternate routes, called collateral circulation.

True

Motor unit recruition is when more than one lower motor neuron is activated by the motor cortex.

True

Muscle action potentials rise at the neuromuscular junctions.

True

Muscle fibers are are composed of myofibrils. The myofibrils are composed of repeated units called sarcomeres, which are the basic functional units of the muscle fiber. The sarcomere is responsible for the striated appearance of skeletal muscle and forms the basic machinery necessary for muscle contraction.

True

Second Line of Defense also called Internal Defenses are four main types of antimicrobial substances that discourage microbial growth: (1) interferons, (2) complement, (3) iron-binding proteins, and (4) antimicrobial proteins. Lymphocytes, macrophages, and fibroblasts infected with viruses produce proteins called interferons (IFNs). A group of normally inactive proteins in blood plasma and on plasma membranes makes up the complement system. Iron-binding proteins inhibit the growth of certain bacteria by reducing the amount of available iron. Antimicrobial proteins are short peptides that have a broad spectrum of antimicrobial activity.

True

Skeletal muscle tissue contracts only when stimulated by acetylcholine released by a nerve impulse in a motor neuron. In contrast, cardiac muscle tissue contracts when stimulated by its own autorhythmic muscle fibers. Under normal resting conditions of the body, cardiac muscle tissue contracts and relaxes about 75 times a minute.

True

Skeletal muscle tissue is one of three major muscle types, the others being cardiac muscle and smooth muscle tissues. It is a form of striated muscle tissue which is under the voluntary control of the somatic nervous system. A skeletal muscle as a functional unit or organ, refers to multiple bundles (fascicles) of muscle fibers. The fibers, the bundles and the muscles are surrounded by connective tissue layers. Enclosing each muscle fiber is a layer of connective tissue called the endomysium; enclosing each fascicle is a layer called the perimysium, and enclosing each muscle is a layer of connective tissue known as the epimysium. Independent muscles are separated by fasciae. Muscle fibers are in turn are composed of myofibrils. The myofibrils are composed of repeated in units called sarcomeres, which are the basic functional units of the muscle fiber. The sarcomere is responsible for the striated appearance of skeletal muscle and forms the basic machinery necessary for muscle contraction.

True

Skeletal muscle tissue is so named because most skeletal muscles move the bones of the skeleton. A few skeletal muscles attach to and move the skin or other skeletal muscles. Skeletal muscle tissue is striated: Alternating light and dark protein bands (striations) are seen when the tissue is examined with a microscope. Skeletal muscle tissue works in a voluntary manner. Its activity can be consciously controlled by neurons (nerve cells) that are part of the somatic (voluntary) division of the nervous system.

True

Skeletal muscle tissue is so named because they move the bones of the skeleton

True

Skeletal muscles are composed of tubular muscle cells (myocytes called muscle fibers or myofibers) which are formed in a process known as myogenesis. Muscle fibers contain numerous tubular myofibrils. Myofibrils are composed of repeating sections of sarcomeres, which appear under the microscope as alternating dark and light bands.

True

Skeletal muscles are well supplied with nerves and blood vessels. Generally, an artery and one or two veins accompany each nerve that penetrates a skeletal muscle. The neurons that stimulate skeletal muscle to contract are somatic motor neurons. Each somatic motor neuron has a threadlike axon that extends from the brain or spinal cord to a group of skeletal muscle fibers. The axon of a somatic motor neuron typically branches many times, each branch extending to a different skeletal muscle fiber.

True

Smooth muscle is an involuntary non-striated muscle. It is divided into two subgroups: the single-unit and multiunit smooth muscle.

True

The sarcoplasm, the cytoplasm of a muscle fiber includes a substantial amount of glycogen, which is a large polymer composed of many glucose molecules. Glycogen can be used for synthesis of ATP. In addition, the sarcoplasm contains a red‐colored protein called myoglobin. This protein, found only in muscle, binds oxygen molecules that diffuse into muscle fibers from interstitial fluid. Myoglobin releases oxygen when it is needed by the mitochondria for ATP production. The mitochondria lie in rows throughout the muscle fiber, strategically close to the contractile muscle proteins that use ATP during contraction so that ATP can be produced quickly as needed

True

The second type of smooth muscle tissue, multi‐unit smooth muscle tissue, consists of individual fibers, each with its own motor neuron terminals and with few gap junctions between neighboring fibers. Stimulation of one multi‐unit fiber causes contraction of that fiber only. Multi‐unit smooth muscle tissue is found in the walls of large arteries, in airways to the lungs, in the arrector pili muscles that attach to hair follicles, in the muscles of the iris that adjust pupil diameter, and in the ciliary body that adjusts focus of the lens in the eye.

True

The shapes of cells also vary considerably. They may be round, oval, flat, cube-shaped, column-shaped, elongated, star-shaped, cylindrical, or disc-shaped. A cell's shape is related to its function in the body.

True

The skin and mucous membranes of the body are the first line of defense against pathogens. These structures provide both physical and chemical barriers that discourage pathogens and foreign substances from penetrating the body and causing disease

True

When a person is in conscious state, even at rest, a skeletal muscle exhibits muscle tone, a small amount of tension in the muscle due to weak, contractions of its motor units. Muscle tone keeps skeletal muscles firm, but it does not result in a force strong enough to produce movement. For example, when you are awake, the muscles in the back of the neck are in normal tonic contraction; they keep the head upright and prevent it from slumping forward on the chest. When the person sleeps or is under deep anesthesia no muscle tone is exhibited.

True

When microbes penetrate the skin and mucous membranes or bypass the antimicrobial substances in blood, the next nonspecific defense consists of natural killer cells and phagocytes. About 5-10% of lymphocytes in the blood are natural killer (NK) cells. They are also present in the spleen, lymph nodes, and red bone marrow. NK cells have the ability to kill a wide variety of infected body cells and certain tumor cells. NK cells attack any body cells that display abnormal or unusual plasma membrane proteins.

True

Whole blood has two components: (1) blood plasma, a watery liquid extracellular matrix that contains dissolved substances, and (2) formed elements, which are cells and cell fragments. If a sample of blood is centrifuged (spun) in a small glass tube, the cells (which are more dense) sink to the bottom of the tube while the plasma (which is less dense) forms a layer on top. Blood is about 45% formed elements and 55% blood plasma. Normally, more than 99% of the formed elements are cells named for their red color—red blood cells (RBCs). Pale, colorless white blood cells (WBCs) and platelets occupy less than 1% of the formed elements. Because they are less dense than red blood cells but more dense than blood plasma, they form a very thin buffy coat layer between the packed RBCs and plasma in centrifuged blood. Figure 19.1b shows the composition of blood plasma and the numbers of the various types of formed elements in blood.

True

With its many layers of closely packed, keratinized cells, the outer epithelial layer of the skin—the epidermis—provides a formidable physical barrier to the entrance of microbes. In addition, periodic shedding of epidermal cells helps remove microbes at the skin surface. Bacteria rarely penetrate the intact surface of healthy epidermis. If this surface is broken by cuts, burns, or punctures, however, pathogens can penetrate the epidermis and invade adjacent tissues or circulate in the blood to other parts of the body.

True

Within a particular motor unit, all of the skeletal muscle fibers are of the same type. The different motor units in a muscle are recruited in a specific order, depending on need. Activation of various motor units is controlled by the brain and spinal cord.

True

Within myofibrils are smaller protein structures called filaments or myofilaments. Thin filaments are composed mostly of the protein actin, while thick filaments are composed of the protein myosin.

True

Within single-unit smooth muscle cells, the whole bundle or sheet contracts as a syncytium (i.e. a multinucleated piece of interconnected cells that contracts and relaxes as a unit). Multiunit smooth muscle tissues are built from many individual cells.

True

two strands of the double helix separate by breaking the hydrogen bonds (shown as dotted lines) between nucleotides. New, complementary nucleotides attach at the proper sites, and a new strand of DNA is synthesized alongside each of the original strands. This process is called DNA replication.

True

Which layer of the arterial wall is responsible for vasoconstriction?

Tunica media

The following is a particular sequence of codon on mRNA: ACU. What is the corresponding anti-codon for the tRNA?

UGA

Which of the following blood vessels carries blood from the tissues back to the heart?

Veins

In resting individuals, which vessels serve as a large blood reservoir from which blood can be quickly diverted to other vessels as needed?

Veins and venules

Anemia is defined as ...

a condition in which the oxygen-carrying capacity of blood is reduced

Which of the following can stimulate artificially acquired active immunity ?

administration of a vaccine administration of a toxin that has been heat treated to inactivate it

Blood is often drawn from the front of the elbow at the _______ region.

antecubital

What type of tendon is formed when the connective tissue elements of a skeletal muscle extend as a broad flat layer?

aponeurosis

Which of the following carries blood away from the heart to other organs?

arteries

If a doctor listens to a gurgling noise within the gastrointestinal tract, he/she is performing ...

auscultation

Which of the following correctly lists the sequence of structures that action potentials must move on to excite skeletal muscle contraction?

axon of neuron, sarcolemma, T tubules

The largest driving force for pulling fluid from the interstitial spaces back into the capillaries is ...

blood colloidal osmotic pressure

At the neuromuscular junction, _______must enter the synaptic end bulb to stimulate the release of ____________, which binds to ligand gates so ________can enter the muscle fiber. (ACh = acethylcholine)

calcium ions; ACh; sodium ions

Contraction of myofibrils within a muscle fiber begins when ...

calcium is released from the sarcoplasmic reticulum

The difference between a person's maximum cardiac output and resting cardiac output is called the ...

cardiac reserve

Which cellular organelle is comprised of a pair of centrioles and the surrounding pericentriolar material (area).

centrosome

The difference in concentration of a specific chemical, like Na+, on the inside and outside of a plasma membrane is referred as a(n) ...

concentration variant

The branches from the ascending aorta that supply blood to the cardiac muscle are the ...

coronary arteries

The circulatory system aids in the homeostasis of the skeletal system by ...

delivering calcium delivering phosphate transporting hormones for bone metabolism transporting hormones for production of red blood cells

The shaft of a long bone is the

diaphysis

The process of a white blood cell squeezing between endothelial cells to exit a blood vessel is called ...

emigration or diapedesis

This type of membrane protein enables cells to catalyze specific chemical reactions at the inner or outer surface of their plasma membrane.

enzymes

Before ossification, the ______ is composed of hyaline cartilage and allows the diaphysis to grow in length

epiphyseal plate

The _______ is the name of the entire region of long bone toward the end of the diaphysis that contained hyaline cartilage used for growth in length.

epiphyseal plate

Which of the following formed elements in blood is removed by fixed macrophages in the spleen and liver after around 120 days in the circulation?

erythrocytes

Capillaries are also referred to as ...

exchange vessels

What are the nonpolar parts of phospholipids?

fatty acid tail groups

The major function of red blood cells is ...

gas transport

The major function of mitochondria is to ...

generate ATP

Cardiac output is dependent on both

heart rate and stroke volume

What is the major function of histones?

help organize coiling and folding of the DNA

Nutrients from digested food enter the liver via the ...

hepatic portal circulation

Motor unit recruitment occurs when there is a(n) ....................... in the number of active motor units within a skeletal muscle.

increase

Which body process is controlled using a positive feedback loop?

increasing strength of uterine contractions in response to cervical stretch

The femoral area is _____to the cervical area?

inferior

Which of the following microscopic structures is only found in the cardiac muscle tissue?

intercalated discs

Which body fluid fills the narrow spaces between cells and tissues?

interstitial fluid

The ribs are _____ to the sternum.

lateral

The epithelial layer of mucous membranes .............. (Select all that apply.)

line body cavities secretes a fluid called mucus has lubricates and moistened cavity surface.

Which of the following membrane-enclosed organelles can engulf a worn-out organelle, digest its chemical components, and recycle those digested components?

lysosomes

The pericardial cavity is located inside the ...

mediastinum

Which functions do muscles perform in general?

moving and storing material throughout the body generating heat through contractions stabilizing the movement of joints promoting movement of body structures

The mucous membrane of the nose has ............

mucus-coated hairs that trap and filter microbes, dust, and pollutants from inhaled air.

The contractile elements of a skeletal muscle fiber are thread-like structures called ...

myofibrils

What is the site of synthesis of rRNA and assembly of rRNA and proteins into ribosomal subunits?

nucleous

Specialized structures within a cell that have a characteristic shape and perform specific functions in cellular growth, maintenance are called ...

organelles

Which cavity contains the heart?

pericardial cavity

The membrane that surrounds and protects the heart is called the ...

pericardium

The three main components of the lipid bilayer portion of a plasma membrane are ...

phospholipids, cholesterol, and glycolipids

The skin and mucous membranes of the body are the first line of defense against pathogens. These structures provide ............... and ..... (Select all that apply.)

physical barriers chemical barriers discouraging pathogens and foreign substances from penetrating the body and causing disease.

Serum is ...

plasma without clotting factors and fibrogen

Which of the following structures is used to control the flow of blood through a capillary bed?

precapillary sphincters

Structural organization of proteins

primary, secondary, tertiary, quaternary

A cell lacking ribosomes would be unable to make what organic compound?

proteins

Lymphatic capillaries, because of their greater permeability than blood capillaries, can readily absorb which molecules that are NOT easily absorbed by blood capillaries? Select all that apply.

proteins lipids

A component that detects decreasing oxygen concentrations in blood would be a ...

receptor

Feeling the presence of a mosquito biting your arm is an example of ______;

responsiveness

Which of the following membrane-enclosed organelle is the site of synthesis of membrane proteins and secretory proteins?

rough endoplasmic reticulum

Most smooth muscle fibers contract or relax in response to action potentials from the autonomic nervous system. In addition, many smooth muscle fibers contract or relax in response to .........

stretching hormones changes in pH oxygen and carbon dioxide levels temperature ion concentrations

When action potentials are conducted through the T-tubules, C++ ions will be released from ...

terminal cisternae of the sarcoplasmic reticulum

Most skeletal muscles are a mixture of three types of skeletal muscle fibers; about half of the fibers in a typical skeletal muscle are slow oxidative (SO) fibers. However, the proportions vary somewhat, depending on ...............

the action of the muscle the person's training regimen genetic factors

If a patient is confined to bed and is unable to walk at all, which of the following will be seriously affected?

the circulation returning from the lower body

Which of the following is a measure of a solution's ability to change the volume of cells by altering their water content?

tonicity

Which of the following transport processes moves substances through cells using endocytosis on one side of a cell and exocytosis on the opposite side of the cell?

transcytosis

Which type of membrane protein extends across the entire lipid bilayer of the plasma membrane touching both intracellular fluid and the extracellular fluid?

transmembrane protein

A brief contraction of all muscle fibers in a motor unit in response to a single action potential moving down the somatic motor neuron is known as ...

twitch contraction

Put the cavities in order from broadest to most specific in which the lungs are located

ventral, thoracic, parietal pleura, visceral pleura

phagocytosis

vital defense mechanism that helps protect the body from disease

What is the major difference between lymph and interstitial fluid?

Location

The average life span of an erythrocyte in the circulation is ...

120 days

What percentage of blood plasma is water?

91.5%

Which of the following regions of a muscle fiber contain thin filaments?

Both the A and I band

When your fingers touch your shoulder, they are considered ________ from the shoulder?

Distal

Which of the following is a function of the lymphatic system?

Drain excessive interstitial fluid Transport dietary lipids Carry out immune responses

The visceral layer of the serous pericardium is also considered to be the ...

Epicardium

This is the outermost layer of connective tissue surrounding a skeletal muscle.

Epimysium

What causes lymph from the small intestines to appear white?

Lipids

During this phase of cell division, organelles duplicate and centrosome replication begins.

Interphase

Most intravenous solutions are _____ with respect to blood cells?

Isotonic

When holding your arms out to the side at shoulder level, your fingers are ________from your midline.

Lateral

Where would an appendectomy be preformed

Left illiac region

Which of the following chambers of the heart is surrounded by the thickest layer of myocardium?

Left ventricle

Which of the following terms identifies the anatomical space found between the lungs that extends from the sternum to the vertebral column and from the first rib to the diaphragm?

Mediastinum

Cutting open the chest at the sternal medial vertical marking would represent a(n)

Midsaggital line

Which of the following consists of a somatic motor neuron and all the skeletal muscle fibers it stimulates?

Motor unit

Which layer of the heart wall consists of cardiac muscle tissue?

Myocardium

Which of the following functions as a motor protein in all three types of muscle tissue?

Myosin

Which type of immunity defends against any type of invader?

Nonspecific

Which of the following protects the contents of the nucleus?

Nuclear envelope

Which plane divides the body into unequal right and left halves?

Parasaggital plane

During phagocytosis, binding of a particle to a plasma membrane receptor triggers formation of _____, which are extensions of the plasma membrane of the phagocyte that eventually surround the particle forming a phagosome.

Pseudopods (false feet)

Hematocrit is a ............ portion of the blood.

RBC

Which of the following types of membrane proteins function by recognizing and binding to hormones and neurotransmitters?

Receptors

Which of the following are signs of inflammation? Select all that applies

Redness Pain Swelling Heat Loss of function

If someone receives CPR, compressions will be performed on the ______area.

Sternal

Which characteristics describe both skeletal and cardiac muscle?

Striations

Major function of the blood .....

Transportation of nutrients Regulation of pH Protection against infectious disease Transportation of heat

Cutting the body in half at the diaphragm, would separate the thoracic cavity and the abdominopelvic cavity. What plane would create these halves?

Transverse

A ECG is a recording of the electrical activity that initiates each heartbeat. Analysis of an ECG involves measuring the time spans between waves, which are called intervals or segments.

True

A motor neuron and all the muscle fibers innervated by that neuron is called a motor unit.

True

A motor neuron is a nerve cell type whose cell body is in the motor cortex, brainstem or the spinal cord, and whose axon (fiber) contributes to the motor fibers of the peripheral nerves. A motor unit is made up of a motor neuron and the skeletal muscle fibers innervated by that motor neuron's axonal terminals. Groups of motor units work together to coordinate the contractions of a single muscle; all the motor units within a muscle are considered a motor pool.

True

A sarcomere is the unit of striated muscle tissue. It is the repeating unit between two Z lines. Sarcomeres are composed of long, fibrous proteins as filaments that slide past each other when a muscle contracts or relaxes.

True

A vascular sinus is a thin-walled vein that has no smooth muscle to alter its diameter.

True

According to the fluid mosaic model, the membrane is a mosaic of proteins floating like icebergs in a lipid bilayer sea.

True

The process in which the numbers of active motor units increases is called motor unit recruitment.

True

Acquired immunodeficiency syndrome (AIDS) is a condition in which a person experiences a telltale assortment of infections due to the progressive destruction of immune system cells by the human immunodeficiency virus (HIV). AIDS represents the end stage of infection by HIV. A person who is infected with HIV may be symptom-free for many years, even while the virus is actively attacking the immune system. In the two decades after the first five cases were reported in 1981, 22 million people died of AIDS. Worldwide, 35 to 40 million people are currently infected with HIV.HIV Transmission Because HIV is present in the blood and some body fluids, it is most effectively transmitted (spread from one person to another) by actions or practices that involve the exchange of blood or body fluids between people. HIV is transmitted in semen or vaginal fluid during unprotected (without a condom) anal, vaginal, or oral sex. HIV also is transmitted by direct blood-to-blood contact, such as occurs among intravenous drug users who share hypodermic needles or health-care professionals who may be accidentally stuck by HIV-contaminated hypodermic needles. In addition, HIV can be transmitted from an HIV-infected mother to her baby at birth or during breast-feeding. The chance of transmitting or of being infected by HIV during vaginal or anal intercourse can be greatly reduced—although not entirely eliminated—by the use of latex condoms. Public health programs aimed at encouraging drug users not to share needles have proved effective at checking the increase in new HIV infections in this population. Also, giving certain drugs to pregnant HIV-infected women greatly reduces the risk of transmission of the virus to their babies. HIV is a very fragile virus; it cannot survive for long outside the human body. The virus is not transmitted by insect bites. One cannot become infected by casual physical contact with an HIV-infected person, such as by hugging or sharing household items. The virus can be eliminated from personal care items and medical equipment by exposing them to heat (135°F for 10 minutes) or by cleaning them with common disinfectants such as hydrogen peroxide, rubbing alcohol, household bleach, or germicidal cleansers such as Betadine or Hibiclens. Standard dishwashing and clothes washing also kill HIV.

True

Actin molecules are bound to the Z line, which forms the borders of the sarcomere.

True

After birth, the heart pumps blood into two closed circuits with each beat—systemic circulation and pulmonary circulation. The two circuits are arranged in series: The output of one becomes the input of the other, as would happen if you attached two garden hoses. The left side of the heart is the pump for systemic circulation; it receives bright red oxygenated blood from the lungs. The left ventricle ejects blood into the aorta. From the aorta, the blood divides into separate streams, entering progressively smaller systemic arteries that carry it to all organs throughout the body—except for the air sacs (alveoli) of the lungs, which are supplied by the pulmonary circulation. In systemic tissues, arteries give rise to smaller-diameter arterioles, which finally lead into extensive beds of systemic capillaries. Exchange of nutrients and gases occurs across the thin capillary walls. Blood unloads O2 (oxygen) and picks up CO2 (carbon dioxide). In most cases, blood flows through only one capillary and then enters a systemic venule. Venules carry deoxygenated blood away from tissues and merge to form larger systemic veins. Ultimately the blood flows back to the right atrium of the heart.

True

After the cross-bridges formed, the power stroke occurs.

True

Although bones provide leverage and form the framework of the body, they cannot move body parts by themselves. Motion results from the alternating contraction and relaxation of muscles, which make up 40-50% of total adult body weight. Muscular strength reflects the primary function of muscle—the transformation of chemical energy into mechanical energy to generate force, perform work, and produce movement

True

Although the principles of contraction are similar, smooth muscle tissue exhibits some important physiological differences from cardiac and skeletal muscle tissue. Contraction in a smooth muscle fiber starts more slowly and lasts much longer than skeletal muscle fiber contraction. Another difference is that smooth muscle can both shorten and stretch to a greater extent than the other muscle types.

True

Among internal defenses is phagocytosis. Phagocytes are specialized cells that perform phagocytosis, the ingestion of microbes or other particles such as cellular debris. The two major types of phagocytes are neutrophils and macrophages. When an infection occurs, neutrophils and monocytes migrate to the infected area. During this migration, the monocytes enlarge and develop into actively phagocytic macrophages called wandering macrophages. Other macrophages, called fixed macrophages, stand guard in specific tissues

True

Antigens have two important characteristics: (1) immunogenicity and (2) reactivity. Immunogenicity is the ability to provoke an immune response by stimulating the production of specific antibodies, the proliferation of specific T cells, or both. Reactivity is the ability of the antigen to react specifically with the antibodies or cells it provoked.

True

Antigens that get past the innate defenses generally follow one of three routes into lymphatic tissue: (1) Most antigens that enter the bloodstream (for example, through an injured blood vessel) are trapped as they flow through the spleen. (2) Antigens that penetrate the skin enter lymphatic vessels and lodge in lymph nodes. (3) Antigens that penetrate mucous membranes are entrapped by mucosa-associated lymphatic tissue (MALT).

True

Approximately, 280 million hemoglobin molecules are found in each RBC

True

As action potentials propagate through the heart, they generate electrical currents that can be detected at the surface of the body. An electrocardiogram, abbreviated either ECG or EKG (from the German word Elektrokardiogram), is a recording of these electrical signals. The ECG is a composite record of action potentials produced by all of the heart muscle fibers during each heartbeat. The instrument used to record the changes is an electrocardiograph.

True

Attached to the lymphatic capillaries are anchoring filaments, which contain elastic fibers. They extend out from the lymphatic capillary, attaching lymphatic endothelial cells to surrounding tissues. When excess interstitial fluid accumulates and causes tissue swelling, the anchoring filaments are pulled, making the openings between cells even larger so that more fluid can flow into the lymphatic capillary. Lymphatic capillaries have greater permeability than blood capillaries and thus can absorb large molecules such as proteins and lipids.

True

Because mature skeletal muscle fibers have lost the ability to undergo cell division, growth of skeletal muscle after birth is due mainly to hypertrophy, the enlargement of existing cells, rather than to hyperplasia, an increase in the number of fibers. Satellite cells divide slowly and fuse with existing fibers to assist both in muscle growth and in repair of damaged fibers.

True

Muscle tissue is a specialized soft tissue found in animals which functions by contracting forcefully, thereby applying forces to different parts of the body. The three muscle tissue types are: (1) skeletal or striated muscle; (2) smooth or non-striated muscle; and (3) cardiac muscle, which is sometimes known as semi-striated. Muscle tissues consist of elongated multicellular structures called myofibers contributing into independent organs such as heart, skeletal muscle and to the walls of other tube- or bag-like organs by sheets and fibers of connective tissue. Muscle tissues contain special proteins called contractile proteins such as actin and myosin, which forcefully contract (shorten) and relax (expand to its original length) causing movement. Muscle tissues vary with function and location in the body. Skeletal muscle contracts and relaxes only under voluntary control, smooth and cardiac muscle contracts involuntarily, without conscious intervention. All these three muscle tissue types may be activated both through the interaction of the nervous system or by receiving hormonal signals from endocrine system.

True

Muscle tissues vary with function and location in the body. Skeletal muscle contracts and relaxes only under voluntary control, smooth and cardiac muscle contracts involuntarily, without conscious intervention. All these three muscle tissue types may be activated both through the interaction of the nervous system or by receiving hormonal signals from endocrine system.

True

Muscles are attached to bones by tendons at their origin and insertion

True

Muscles require innervation to function. In the neuromuscular system nerves from the central nervous system and the peripheral nervous system are linked and work together with muscles as motor units. Muscles will contract or relax when they receive signals from the nervous system. The neuromuscular junction is the site of the signal exchange which is a chemical synapse between a motor neuron and a muscle fiber. It allows the motor neuron to transmit a signal to the muscle fiber, causing muscle contraction. At the neuromuscular junction presynaptic motor axons terminate at the cell membrane or sarcolemma of a muscle fiber. The sarcolemma at the junction has invaginations called postjunctional folds, which increase its surface area facing the synaptic cleft. These postjunctional folds form the motor endplate, which is studded with acetylcholine receptors. The presynaptic axons terminate in bulges called terminal boutons (or presynaptic terminals) that project toward the postjunctional folds of the sarcolemma.

True

Myosin can only bind to actin when the binding sites on actin are exposed by the action of calcium ions on troponin/tropomyosin complex.

True

Narrow, plate‐shaped regions of dense protein material called Z discs separate one sarcomere from the next. Thus, a sarcomere extends from one Z disc to the next Z disc.

True

Negative feedback regulation of blood pressure is via baroreceptor reflexes.

True

Nervous system regulation of the heart in the cardiovascular center originates in the medulla oblongata.

True

Neutrophil is a blood cell type which is a phagocyte.

True

Nucleic acids, so named because they were first discovered in the nuclei of cells, are huge organic molecules that contain carbon, hydrogen, oxygen, nitrogen, and phosphorus.

True

Nutrients are not able to diffuse quickly enough from blood in the chambers of the heart to supply all layers of cells that make up the heart wall. For this reason, the myocardium has its own network of blood vessels, the coronary circulation or cardiac circulation. The coronary arteries branch from the ascending aorta and encircle the heart like a crown encircles the head. While the heart is contracting, little blood flows in the coronary arteries because they are squeezed shut. When the heart relaxes, however, the high pressure of blood in the aorta propels blood through the coronary arteries, into capillaries, and then into coronary veins.

True

Of the two types of smooth muscle tissue, the more common type is visceral single unit smooth muscle tissue.

True

Once activated, a B cell undergoes clonal selection, forming a clone of plasma cells and memory cells. Plasma cells are the effector cells of a B cell clone; they secrete antibodies

True

Only the heart contains cardiac muscle tissue, which forms most of the heart wall. Cardiac muscle is also striated, but its action is involuntary. The alternating contraction and relaxation of the heart is not consciously controlled. Rather, the heart beats because it has a natural pacemaker that initiates each contraction.

True

Proteins exhibit four levels of structural organization. The primary structure is the unique sequence of amino acids that are linked by covalent peptide bonds to form a polypeptide chain. A protein's primary structure is genetically determined, and any changes in a protein's amino acid sequence can have serious consequences for body cells.

True

Red blood cells also contain the enzyme carbonic anhydrase (CA), which catalyzes the conversion of carbon dioxide and water to carbonic acid, which in turn dissociates into H+ and HCO3−. The entire reaction is reversible

True

Red bone marrow contains stem cells that develop into lymphocytes.

True

Redness results from increased blood flow due to vasodilation; pain, from injury of nerve fibers, irritation by microbial toxins, kinins, and prostaglandins, and pressure due to edema; heat, from increased blood flow and heat released by locally increased metabolic reactions; swelling, from leakage of fluid from capillaries due to increased permeability.

True

Reproductive cell division is the mechanism that produces gametes, the cells needed to form the next generation of sexually reproducing organisms. This process consists of a special two-step division called meiosis, in which the number of chromosomes in the nucleus is reduced by half.

True

Sebaceous (oil) glands of the skin secrete an oily substance called sebum that forms a protective film over the surface of the skin. The acidity of the skin (pH 3-5) is caused in part by the secretion of fatty acids and lactic acid. The unsaturated fatty acids in sebum inhibit the growth of certain pathogenic bacteria and fungi.

True

Smooth muscle is an involuntary non-striated muscle. It is divided into two subgroups: the single-unit and multiunit smooth muscle. Within single-unit cells, the whole bundle or sheet contracts as a syncytium (i.e. a multinucleated piece of interconnected cells that contracts and relaxes as a unit). Multiunit smooth muscle tissues are built from many individual cells. Smooth muscle is found within the walls of blood vessels (such smooth muscle specifically being termed vascular smooth muscle) such as in the tunica media layer of large (aorta) and small arteries, arterioles and veins. Smooth muscle is also found in lymphatic vessels, the urinary bladder, uterus (termed uterine smooth muscle), male and female reproductive tracts, gastrointestinal tract, respiratory tract, arrector pili of skin, the ciliary muscle, and iris of the eye. The structure and function are basically the same in smooth muscle cells in different organs, but the inducing stimuli differ substantially, in order to perform individual effects in the body at individual times. In addition, the glomeruli of the kidneys contain smooth muscle-like cells called mesangial cells.

True

Smooth muscle tissue is located in the walls of hollow internal structures, such as blood vessels, airways, and most organs in the abdominopelvic cavity. It is also found in the skin, attached to hair follicles. Under a microscope, this tissue lacks the striations of skeletal and cardiac muscle tissue, hence it is called being smooth. The action of smooth muscle is usually involuntary, and some smooth muscle tissue, such as the muscles that propel food through your gastrointestinal tract, has autorhythmicity. Both cardiac muscle and smooth muscle are regulated by neurons that are part of the autonomic (involuntary) division of the nervous system and by hormones released by endocrine glands.

True

Substances such as bacteria, toxins, viruses, and foreign tissues that are recognized as foreign and provoke immune responses are called antigens, meaning antibody generators. The ability of the body to defend itself against specific invading agents is called adaptive (specific) immunity. The branch of science and medicine that deals with the responses of the body when challenged by antigens is called immunology. The immune system includes the cells and tissues that carry out immune responses. The adaptive immunity involves lymphocytes called B cells and T cells.

True

The Rh blood group is so named because the Rh anitigen, called Rh factor, was first found in the blood of the Rhesus monkey.

True

The Rh blood group is so named because the Rh antigen, called Rh factor, was first found in the blood of the Rhesus monkey.

True

The alternate route of blood flow to a body part is called anastomosis.

True

The anulus fibrosus of the heart (atrioventricular septum) serves as a point of insertion for bundles of cardiac muscle fibers and acts as an electrical insulator between the atria and ventricles.

True

The binding of NK cells to a target cell, such as an infected human cell, causes the release of granules containing toxic substances from NK cells. Some granules contain a protein called perforin that inserts into the plasma membrane of the target cell and creates channels (perforations) in the membrane. As a result, extracellular fluid flows into the target cell and the cell bursts, a process called cytolysis

True

The central part of the thoracic cavity is an anatomical region called the mediastinum. It is between the lungs, extending from the sternum to the vertebral column and from the first rib to the diaphragm. The mediastinum contains all thoracic organs except the lungs themselves. Among the structures in the mediastinum are the heart, esophagus, trachea, thymus, and several large blood vessels that enter and exit the heart.

True

The environment in which we live is filled with microbes that have the ability to cause disease if given the right opportunity. If we did not resist these microbes, we would be ill constantly or even die. Fortunately, we have a number of defenses that keep microbes from either entering our bodies or combat them if they do gain entrance. The lymphatic system is one of the principal body systems that helps to defend us against disease-producing microbes.

True

The epithelial layer of mucous membranes, which line body cavities, secretes a fluid called mucus that lubricates and moistens the cavity surface. Because mucus is slightly viscous, it traps many microbes and foreign substances.

True

The field of psychoneuroimmunology (PNI) deals with communication pathways that link the nervous, endocrine, and immune systems. PNI research appears to justify what people have long observed: Your thoughts, feelings, moods, and beliefs influence your level of health and the course of disease. For example, cortisol, a hormone secreted by the adrenal cortex in association with the stress response, inhibits immune system activity. If you want to observe the relationship between lifestyle and immune function, visit a college campus. As the semester progresses and the workload accumulates, an increasing number of students can be found in the waiting rooms of student health services. When work and stress pile up, health habits can change. Many people smoke or consume more alcohol when stressed, two habits detrimental to optimal immune function. Under stress, people are less likely to eat well or exercise regularly, two habits that enhance immunity. People resistant to the negative health effects of stress are more likely to experience a sense of control over the future, a commitment to their work, expectations of generally positive outcomes for themselves, and feelings of social support. To increase your stress resistance, cultivate an optimistic outlook, get involved in your work, and build good relationships with others. Adequate sleep and relaxation are especially important for a healthy immune system. But when there aren't enough hours in the day, you may be tempted to steal some from the night. While skipping sleep may give you a few more hours of productive time in the short run, in the long run you end up even farther behind, especially if getting sick keeps you out of commission for several days, blurs your concentration, and blocks your creativity. Even if you make time to get 8 hours of sleep, stress can cause insomnia. If you find yourself tossing and turning at night, it's time to improve your stress management and relaxation skills! Be sure to unwind from the day before going to bed.

True

The fleshy portion of the muscle between the tendons is called the belly (body).

True

The fused cells of the skeletal muscle tissue are termed skeletal muscle fibers. Each muscle fiber contains hundreds of myofibrils. Within myofibrils are thin and thick filaments arranged as sarcomere. Sarcomeres are the contractile units in all muscle tissue types

True

The layer of a blood vessel that is in direct contact with the blood is the tunica interna while the layer of the vessel that is made up of smooth muscle and elastic fibers is the tunica media.

True

The long left thoracic duct begins as a dilation called the cisterna chyli anterior to the second lumbar vertebra. The cisterna chyli receives lymph from the right and left lumbar trunks and from the intestinal trunk.

True

The lymph passage from the lymph trunks to the venous system differs on the right and left sides of the body. On the right side the three lymph trunks (right jugular trunk, right subclavian trunk, and right broncho mediastinal trunk) usually open independently into the venous system on the anterior surface of the junction of the internal jugular and subclavian veins. On the left side of the body, the largest lymph vessel, the thoracic (left lymphatic) duct forms the main duct for return of lymph to the blood.

True

The lymphatic or lymphoid system consists of a fluid called lymph, vessels called lymphatic vessels that transport the lymph, a number of structures and organs containing lymphatic tissue (lymphocytes within a filtering tissue), and red bone marrow. The lymphatic system assists in circulating body fluids and helps defend the body against disease-causing agents.

True

The lymphatic or lymphoid system consists of a fluid called lymph, vessels called lymphatic vessels that transport the lymph, a number of structures and organs containing lymphatic tissue. The lymphatic system has three primary functions: (1) Drains excess interstitial fluid from tissue spaces and return it to the blood. This function closely links it with the cardiovascular system. In fact, without this function, the maintenance of circulating blood volume would not be possible. (2) Lymphatic vessels transport lipids and lipid-soluble vitamins (A, D, E, and K) absorbed by the gastrointestinal tract. (3) Carries out immune responses; initiates highly specific responses directed against particular microbes or abnormal cells.

True

The main component of the thin filament is the protein actin. Individual actin molecules join to form an actin filament that is twisted into a helix. On each actin molecule is a myosin‐binding site, where a myosin head can attach. Two regulatory proteins—tropomyosin and troponin are also part of the thin filament

True

The more hydrogen ions are dissolved in the solution more acidic it will be; the more hydroxide ions the more basic (alkaline) will be the solution. A solution acidity or alkalinity is expressed on the pH scale which extend 0 to 14.

True

The number of muscle fibers within each motor unit can vary within a muscle and even more from muscle to muscle. The muscles that act on the largest body masses have motor units that contain more muscle fibers, whereas smaller muscles contain fewer muscle fibers in each motor unit. For instance, thigh muscles can have a thousand fibers in each unit, while extraocular muscles might have only ten. Muscles which possess more motor units (and thus have greater individual motor neuron innervation) can control force output more finely. All muscle fibers in a motor unit are of the same fiber type. When a motor unit is activated, all of its fibers contract. The force of a muscle contraction is controlled by the number of activated motor units.

True

The parenchyma (functioning part) of a lymph node is divided into a superficial cortex and a deep medulla.

True

The parenchyma of a lymph node is divided into a superficial cortex and a deep medulla. The cortex consists of an outer cortex and an inner cortex. Within the outer cortex are egg-shaped aggregates of B cells called lymphatic nodules (follicles). The inner cortex does not contain lymphatic nodules. It consists mainly of T cells and dendritic cells that enter a lymph node from other tissues. The dendritic cells present antigens to T cells, causing their proliferation. The newly formed T cells then migrate from the lymph node to areas of the body where there is antigenic activity.

True

The plasma membrane forms the cell's flexible outer surface, separating the cell's internal environment (everything inside the cell) from the external environment (everything outside the cell). It is a selective barrier that regulates the flow of materials into and out of a cell.

True

The principal tissue in the heart wall is cardiac muscle tissue. Between the layers of cardiac muscle fibers are sheets of connective tissue that contain blood vessels, nerves, and the conduction system of the heart. Cardiac muscle fibers have the same arrangement of actin and myosin and the same bands, zones, and Z discs as skeletal muscle fibers. Cardiac muscle tissue has an endomysium and perimysium, but lacks an epimysium.

True

The process by which the formed elements of the blood develop is called hemopoiesis.

True

The sliding filament theory explains the mechanism of muscle contraction based on muscle proteins that slide past each other to generate movement. Huxley was the first to suggest the sliding filament theory in 1953. Using transmission electron microscopy, it was recognized that myosin and actin form overlapping filaments, myosin filaments mainly constituting the A band (the dark region of a sarcomere), while actin filaments traverse both the A and I (light region) bands. According to this theory, the actin (thin) filaments of muscle fibers slide past the myosin (thick) filaments during muscle contraction, while the two groups of filaments remain at relatively constant length. Before the 1950s there were several competing theories on muscle contraction, including electrical attraction, protein folding, and protein modification. The novel theory directly introduced a new concept called cross-bridge theory which explains the molecular mechanism of sliding filament. Cross-bridge theory states that actin and myosin form a protein complex by attachment of myosin head on the actin filament, thereby forming a sort of cross-bridge between the two filaments. The sliding filament theory is a universally accepted explanation of the mechanism that underlies muscle contraction

True

The structure and function are basically the same in smooth muscle cells in different organs, but the inducing stimuli differ substantially, in order to perform individual effects in the body at individual times.

True

The thickness of the myocardium of the four chambers varies according to each chamber's function. The thin-walled atria deliver blood under less pressure into the adjacent ventricles. Because the ventricles pump blood under higher pressure over greater distances, their walls are thicker. Although the right and left ventricles act as two separate pumps that simultaneously eject equal volumes of blood, the right side has a much smaller workload. It pumps blood a short distance to the lungs at lower pressure, and the resistance to blood flow is small. The left ventricle pumps blood great distances to all other parts of the body at higher pressure, and the resistance to blood flow is larger. Therefore, the left ventricle works much harder than the right ventricle to maintain the same rate of blood flow. 1/1

True

The thymus is a bilobed organ located in the mediastinum between the sternum and the aorta. It extends from the top of the sternum or the inferior cervical region to the level of the fourth costal cartilages, anterior to the top of the heart and its great vessels. An enveloping layer of connective tissue holds the two lobes closely together, but a connective tissue capsule encloses each lobe separately. Extensions of the capsule, called trabeculae, penetrate inward and divide each lobe into lobules

True

The thymus, lymph nodes, and spleen are considered organs because each is surrounded by a connective tissue capsule; lymphatic nodules, in contrast, are not considered organs because they lack a capsule, they are component of the organ's wall; - mucosa associated lymphoid tissue (MALT).

True

The widely distributed lymphatic organs and tissues are classified into two groups based on their functions. Primary lymphatic organs are the sites where stem cells divide and become immunocompetent, that is, capable of mounting an immune response. The primary lymphatic organs are the red bone marrow and the thymus. Pluripotent stem cells in red bone marrow give rise to mature, immunocompetent B cells and to pre-T cells. The pre-T cells in turn migrate to the thymus, where they become immunocompetent T cells.

True

The widely distributed lymphatic organs and tissues are classified into two groups based on their functions. The secondary lymphatic organs and tissues are the sites where most immune responses occur. They include lymph nodes, the spleen, and lymphatic nodules (follicles)

True

There are two types of adaptive immunity: cell-mediated immunity and antibody-mediated immunity. Both types of adaptive immunity are triggered by antigens.

True

Those skeletal muscles that produce movements do so by excreting force on tendons, which in turn pull on bones.

True

To describe the location of the many abdominal and pelvic organs clinicians use a method of dividing the abdominopelvic cavity into smaller areas. Two horizontal and two vertical lines partition this cavity into nine abdominopelvic regions. The superior horizontal line, the subcostal line, passes across the lowest level of the 10th costal cartilages; the inferior horizontal line, the transtubercular line, passes across the superior margins of the iliac crests of the right and left hip bone. Two vertical lines, the left and right midclavicular lines, are drawn through the midpoints of the clavicles, just medial to the nipples. The four lines divide the abdominopelvic cavity into a larger middle section and smaller left and right sections. The names of the nine abdominopelvic regions are right hypochondriac, epigastric, left hypochondriac, right lumbar, umbilical, left lumbar, right inguinal (iliac), hypogastric (pubic), and left inguinal (iliac).

True

To locate various body structures, anatomists use specific directional terms, words that describe the position of one body part relative to another. Several directional terms are grouped in pairs that have opposite meanings, such as anterior (front) and posterior (back).

True

Together, all the voluntarily controlled muscles of the body compose the skeletomuscular system.

True

Under a microscope, the smooth muscle tissue lacks the striations of skeletal and cardiac muscle tissue, hence it is called being smooth. The action of smooth muscle is usually involuntary. Both cardiac muscle and smooth muscle are regulated by neurons that are part of the autonomic (involuntary) division of the nervous system and by hormones released by endocrine glands.

True

Unlike striated muscle fibers, smooth muscle fibers can stretch considerably and still maintain their contractile function. When smooth muscle fibers are stretched, they initially contract, developing increased tension. Within a minute or so, the tension decreases. This phenomenon is called the stress-relaxation response.

True

When a motor unit is activated, all of its fibers contract. The force of a muscle contraction is controlled by the number of activated motor units.

True