HSC HUMAN BODY SYSTEMS Midterm Exam October 17, 2001 Department of Anatomy and Cell Biology and Department of Physiology Time: 50 minutes 1.

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1 HSC HUMAN BODY SYSTEMS Midterm Exam October 17, 2001 Department of Anatomy and Cell Biology and Department of Physiology Time: 50 minutes 1. An organ: A. is the smallest independent unit of life B. is composed of two or more tissue types C. of the lymphatic system plays a major role in regulating body temperature D. is always covered on the outside with a serous membrane E. of the skeletal system is responsible for most of the effector responses in the body 2. In anatomical terminology, the region of the neck is referred to as the: A. femoral region B. pectoral region C. brachium region D. cephalic region E. cervical region 3. The mediastinum: A. is located in the abdominal region B. contains the two pleural cavities C. is cephalic to the cervical region D. contains the heart and the great vessels that attach to the heart E. contains the peritoneal cavity 4. One function of the plasma membrane is: A. the synthesis of proteins B. communication between cells C. posttranslational modification of proteins D.to provide mechanical support for cells E. to coordinate the functions of mrna, rrna and titna in protein synthesis 5. In the fluid-mosaic model of the plasma membrane: A. the phospholipid molecules function as receptors for lipid-soluble chemical ligands B. both the shape and the composition of the membrane are constant over time C. the membrane is very rigid and inflexible D. the membrane is fluid enough at body temperature to enable intrinsic proteins to float E. the membrane provides mechanical support for the cell

2 6. Which function is perfomed by the protein components of the plasma membrane: A. regulating the fluidity of the plasma membrane B. functioning as the major source of energy for use in cell metabolism C. functioning as carrier molecules D. ensuring rapid repair after slight damage to the membrane E. enabling closing apposed membranes to fuse, as occurs during exocytosis 7. The transcription of rrna occurs in: A. the ribosomes B. the nucleolus C. the mitochondria D. the smooth endoplasmic reticulum E. chromosomes 8. Identify the CORRECT statement A. gametes have 22 pairs of autosomes B. chromatin is found in the cytoplasm C. trna carries specific amino acids to ribosomes for protein synthesis D. translation is the process by which RNA is made E. cytokinesis refers to the division of the nucleus into two nuclei 9. In meiosis: A. the daughter cells are genetically identical B. the process involves dividing the cytoplasm in two C. there are two sequential divisions of the nucleus D. the cell is going through interphase E. the gametes each receive 1 pair of sex chromosomes 10. When intrinsic proteins carry water soluble molecules across the plasma membrane this process is referred to as: A. mediated transport B. simple diffusion C. endocytosis D. pinocytosis E. phagocytosis 11. The sodium-potassium exchange pump: A. is an example of active transport B. does not require energy expenditure C. exchanges Na and K ions by endocytosis D. is an example of an extrinsic protein B. functions to accumulate N and C ions on the outside of the cell

3 12. If the transport of a water soluble molecule across the plasma membrane is limited by the number of carrier molecules this is referred to as: A. competition B. amplification C. ensheathment D. specificity E. saturation 13. Chemical signals in the microenvironment of the cell: A. are carried across the plasma membrane into the cell by means of cholesterol B. may be taken into the cell by receptor-mediated endocytosis C. can alter the permeability of the membrane and thus facilitate their diffusion into the cell D. can induce autophosphorylation of the receptor, which in turn activates adenylyl cyclase E. can alter G protein activity if they bind to intracellular receptors 14. For the alpha subunit of G proteins in the plasma membrane to be activated: A. a chemical signal must bind directly to the C protein complex B. the three subunits of the G protein complex must stay closely attached to one another C. the alpha subunit must bind GTP instead of CD D. the alpha subunit must be autophosphorylated E. the alpha subunit must be part of an ion channel 15. Intracellular receptors: A. can bind both lipid soluble and lipid insoluble ligands B. can directly affect membrane permeability by inducing opening of an ion channel C. alter transcription of mrna by binding to DNA D. are only found in the cytoplasm E. may activate guanylyl cyclase thus inducing the synthesis of an intracellular messenger molecule 16. Epithelial tissue: A. consists of an abundant extracellular matrix in which are embedded a small number of cells B. is always found covering the surfaces of the body that are exposed to the outside C. lining the inside of blood vessels is of the stratified squamous type D. in which only some of the cells reach the free surface is referred to as transitional epithelium E. always has a smooth free surface that functions to reduce friction

4 17. Identify the function NOT performed by simple epithelium: A. protection B. secretion C. diffusion D. filtration E. absorption 18. Protein fibers of the extracellular matrix that: A. fill spaces between tissues and organs are called elastin fibers B. are strong, flexible and inelastic are called collagen fibers C. are found in a tendon consist of loosely arranged collagen fibers D. are found in the dermis of the skin consist of densely-packed collagen and elastin fibers E. are found in a ligament are synthesized by osteoblasts 19. Hyaline cartilage: A. contains an abundance of elastin protein fibers B. is found only in joints subjected to great pressure (e.g. the knee) C. is found in the external ear D, is avascular E. contains numerous thick bundles of collagen fibers 20. Blood is different from other types of connective tissue in that: A. most of the matrix is produced by cells in other tissues B. the movement of cells within the matrix is greatly restricted C. protein fibers are the most prominent component of the matrix D. it contains only one type of cell E. all of the cells lack nuclei 21. Thrombocytes: A. are a type of leucocyte B. are shaped like a biconcave disk C. play an important role in preventing blood loss D. transport respiratory gases to and from the tissues of the body F. are involved in phagocytosis 22. Skeletal muscle cells: A. are under involuntary control B. are nonstriated C. are multinucleated D. are found in the wall of the heart E. attach to bone by means of ligaments

5 23. Which part (or parts) of a neuron function primarily as receivers of information? A. the soma (cell body) only B. the axon only C. the dendrites only D. the soma and dendrites E. the axon and synaptic terminals 24. Clial cells of the CNS that form a myelin sheath around axons are called: A. microglia B. ependymal cells C. Schwann cells D. astrocytes E. oligodendrocytes 25. Endoneurium: A. is the fascia surrounding Schwann cells and the axons ensheathed by these cells B. is found inside skeletal muscle C. refers to the extensions of the plasma membrane of Schwann cells that form a fatty sheath around axons D. surrounds an entire nerve E. lines the fluid-filled ventricles of the brain 26. A body system consisting of a set of glands that ARE NOT physically connected to one another is the: A. digestive system B. reproductive system C. endocrine system D. urinary system E. lymphatic system 27. The lymphatic system is responsible for: A. maintaining electrolyte, water and acid-base balance in the body B. gaseous exchange between lymph vessels and blood vessels C. the excretion of undigested food material D. controlling many effector responses in the body E. the transportation of fat from the intestines 28. In negative feedback, the role of the effector response is to: A. continually monitor the value of the variable B. move the value of the variable away from its set point C. keep the variable within a normal (limited) range D. always decrease the value of the variable E. coordinate the action of the neural and urinary systems

6 29. Positive feedback: A. is when the effector response drives the value of the variable further and further away from its set point B. is when ligand-gated ion channels allow ions to diffuse until the membrane is maximally depolarized C. happens when thyroid hormone inhibits the secretion of thyroid stimulating hormone from the adenohypophysis D. occurs when elevated levels of glucose in the blood inhibit glucagon secretion b alpha cells of the pancreas E. is a self-amplifying series of events that happens for the sole purpose of maintaining homeostasis 30. The fluidity of the plasma membrane is controlled by: A. glycoprotein B. lipoprotein C. cholesterol D. intrinsic proteins E. glycocalyx 31. Identify the INCORRECT statement: A. endocrine glands secrete chemical signals into ducts B. the hypophyseal portal system controls hormone secretion from the adenohypophysis C. the glucagon receptor activates adenylyl cyclase in cells of the liver by means of G proteins D. the adrenal cortex secretes corticosteroids E. the target tissues of prolactin are the mammary glands and ovaries 32. Nonsteroid hormones: A. are synthesized primarily from cholesterol B. bind to intracellular receptors C. may be amino add derivatives D. are secreted by the adrenal cortex E. alters gene expression when the receptor binds to DNA in the nucleus 33. The hypothalamohypophyseal tract: A. is the bundle of hypothalamic axons that are travelling through the infundibulurn of the pituitary gland B. carries thyroid stimulating hormone to the adenohypophysis C. is an example of a portal system D secretes a hormone that functions to maintain Ca homeostasis E. secretes gonadal hormones

7 34. Identify which of the following IS NOT a tropic hormone secreted by the adenohypophysis A. adrenocorticotropic hormone B. luteinizing hormone C. thyroid-stimulating hormone D. follicle-stimulating hormone E. growth hormone 35. Thyroid hormones: A. are secreted by parafollicular cells of the thyroid gland B. increase the metabolic rate of most cells in the body C. diffuse out of the cells as soon as they are synthesized D. prepare the body for physical activity E. regulate the concentration of critical nutrients in the blood 36. Identify the INCORRECT statement: A. all hormones alter the rate at which specific cellular activities occur B. epinephrine-induced smooth muscle contraction is due to the synthesis of intracellular messenger molecules C. the glucagon receptor functions as an enzyme, undergoing autophosphorylation when bound to glucagon D. the atrial natriuretic receptor affects enzyme activity in kidney cells, which increases the excretion of NC ions in urine E. aldosterone induces an increased reabsorption of 4 by kidney cells by altering gene expression 37. Ion channels in the plasma membrane: A. are formed by extrinsic proteins B. are always openg thus allowing the ions to freely diffuse down their concentration gradients C. differ in the factors controlling their gating D. are nonselective in terms of the ions they permit to diffuse through the channel E. exchange NC ions for C ions across the plasma membrane 38. The nongated K ion channels of the plasma membrane of a neuron: A. open and close in response to the binding of ligands by receptors B. are responsible for changing the ionic permeability of the membrane during the repolarization phase of the action potential C. open more slowly than nongated NC ion channels D. are responsible for changing the ionic permeability of the membrane in response to stimuli E. leads to hyperpolarization of the membrane potential if the extracellular concentration of C ions is decreased

8 39. Local potentials: A. are variable in size depending on the strength of the stimulus B. that arise on different parts of the membrane can summate due to the time constant of the membrane C. undergo spatial decay as they propagate along the axon D. are not found in electrically excitable cells E. undergo temporal summation as determined by the length constant of the membrane 40. In regard to voltage-gated ion channels: A. the NC and K ion channels are differentially sensitive to depolarization B. the IC ion channels are the first to open when the membrane is depolarized C. the N ion channels are responsible for the afterpotential D. threshold is the level of depolarization required to close the channels E. they preferentially open in response to hyperpolarization of the membrane 41. During the depolarization phase of the action potential: A. voltage-gated K ion channels open very fast and stay open for a short time B. the length constant of the membrane controls gating of the ion channels C. the permeability of the membrane to Na+ ions is increased D. the magnitude of the depolarization is variable along the length of the axon E. the passive properties of the plasma membrane determine the amplitude of the depolarization 42. Identify the INCORRECT statement: A. during saltatory conduction of an action potential the depolarizing charge spreads PASSIVELY from node to node B. the plasma membrane of the Node of Ranvier contains a very high density of voltage-gated ion channels C. the Node of Ranvier is the space BETWEEN the myelin sheath of adjacent glial cells D. myelination of axons DECREASES the speed of conduction of an action potential B. an action potential is all-or-none 43. At a synapse: A. neurotransmitters diffuse through protein channels in the membrane of the presynaptic terminal B. Ca ions diffuse into the presynaptic terminal through voltage-gated ion channels C. the postsynaptic potential causes synaptic vesicles to fuse with the membrane of the presynaptic terminal D. ligand-gated Na+ ion channels in the postsynaptic membrane give rise to an inhibitory postsynaptic potential (ll SP) E. there is always a very high density of voltage-gated Na+ ion channels in the membrane of the postsynaptic cell

9 44. Identify the CORRECT statement: A. spatial arid temporal summation of EPSP s and IPSP s determine the amplitude of the action potential B. the divergence of synaptic contacts onto target neurons results in spatial summation of local potentials C. the axon of a projection neuron provides the input to a nucleus, a ganglion, or to an effector structure such as muscle D. an excitatory postsynaptic potential is due to the opening of ligand-gated K ion channels in the postsynaptic membrane E. the number and frequency of action potentials depends on whether the axon is myelinated or unmyelinated 45. Feed-forward inhibition: A. is also called recurrent inhibition B. is involved in the experience-dependent strengthening of local neural circuits C. prevents inhibitory interneurons from modulating the output by projection neurons D. is driven by the input E. decreases the amplitude of action potentials in axons of projection neurons