Human Biology Questions

Human Biology (MLTS2101)

Biological Science - BS

Semester: First Semester

Level: 200

Year: 2014

Answers (200 )

The university of Bamenda Université de Bamenda

Faculty of Science Faculté des Sciences

Department of Biological Sciences Département des Sciences Biologique

FIRST SEMESTER EXAMINATION 2014

HUMAN BIOLOGY (MLTS 2101)

Friday 28

February 2014, 7h30-10h30, Course Instructor: Dr SALAH/SAMJE.

…………………………………………………………………..

Instructions: Answer the questions by selecting the single letter that best answers the

questions (N/B) the right answer is 1 mark and the wrong answer is -0.5 mark)

1. According to the boding filament mechanism of skeletal-muscle contraction, during

contractions: (a) The thick filaments stay the same size but the thin filaments shorten (b) The

sarcomeres shorten. (c) The thin filaments stay the same size but the thick filaments shorten

(d) both thick and thin filaments shorten. (e) none of the above occurs

2. Which of the following is an important function of ATP in skeletal muscle? (a) It is

required for the dissociation of actin from myosin (b) it is hydrolyzed by the ATPase that

pumps calcium ions into the sarcoplasmic reticulum. (c) it is used for the phosphorylation of

myosin. (d) a and b (e) a, b and c

3. At the neuromuscular junction, (a) the release of acetylcholine from the motor neuron

causes an EPP (end plate potential) in the motor end plate (b) acetylcholinesterase inhibits

repolarization of the motor end plate. (c) summation of en-plate potentials is required to

trigger an action potential in the muscle membrane. (d) a and b (e) b and c

4. Which of the following statements regarding the action of curare at the neuromuscular

junction is true? (a) curare is an acetycholine agonist. (b) curare binds to acetylcholine

receptors. (c) curare inhibits acetylchorinease (d) curare inhibits acetylcholine release from

motor neuron terminals (e) a and b

5. Which of the following statements is true with regards to types of skeletal-muscle

contraction? (a) in an isotonic contraction, the load equals the tension produced. (b) in an

isotonic contraction, the load exceeds the tension produced. (c) in a lengthening contraction,

the tension produced exceeds the load (d) isotonic contractions begin as isometric

contractions. (e) none of the above is true

6. which of the following is correct comparison of type I (slow oxidative) skeletal-muscle

fibers and type II B(fast-glycolytic) skeletal muscle fibers?

(a) Type I fibers have fewer mitochondria (b) Type I fibers fatigue faster: (c) Type I fibers

store more glycogen. (d)Type I fibers can generate more tension. (e) Type I fibers have a

smaller diameter

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7. Which of the following statements is true?

(a) nervous stimulation of smooth muscle is always excitatory, where as nervous stimulation

of skeletal muscle may be excitatory or inhibitory. (b) The contractile activity of smooth

muscle may be affected by hormones. (c) smooth muscle may be innervated by both

sympathetic and parasympathetic neurons. (d) a and b (e) b and c

8. Which of the following description of skeletal- and smooth muscle contraction is correct?

(a) Skeletal-muscle contraction requires influx of extracellular Ca

, where as smooth muscle

contraction does not. (b) Skeletal-muscle contraction requires interactions between thick and

thin filaments, where as smooth muscle contraction does not. (c) Skeletal-muscle contraction

results from cross-bridge cycling, where as smooth muscle contraction does not. (d) Skeletal-

muscle contraction requires release of Ca

from sarcoplasmic reticulum, where as smooth

muscle contraction does not. (e) The size of calcium regulation of skeletal-muscle contraction

is on the thin filament, whereas in smooth-muscle contraction it is on the thick filament.

9. which of the following statements regarding myasthenia gravis is true? (a) it is caused by

disuse atrophy. (b) it is caused by a genetic defect In the acetylcholinesterase pathway. (c) it

is caused by a genetic lack of the protein, dystrophin. (d) it is caused by a virus that attacks

motor neurons (e) it is an autoimmune disease that attacks the neuromuscular junction.

10. Muscles in the back have a higher proportion of fast-glycolytic fibers than do muscles in

the arms. (a) True (b) False

11. Muscles in the hands have smaller motor units than muscles in the back. (a) True (b)

False

12. The layer of connective tissue that separates the muscle tissue into smaller sections is

called the ____ (a) aponeuroses (b) epimysium (c) perimysium (d) endomysium (e) none of

these

13. The segment of a myofibril that is called a sarcomere runs from ____ (a) one Z line to the

next Z line (b) one H zone to the next H zone (c) one A band to the next A band (d) one end

of a skeletal muscle to the opposite end (e) a and b

14. The ____ are an invagination of the muscle cell’s sarcolemma. (a) sarcoplasmic reticulum

(b) transverse T tubules (c) cisternae (d)microtubules (e) none of these

15. A motor unit is made up of ___ (a) all the muscle fibers within a given muscle (b) a motor

neuron and the muscle fibers it innervates (c) all the neurons going into an individual section

of the body (d) a fascicle and a nerve (e) c and d

16. Which of these statements is correct regarding muscle contraction?

(a) All motor units act together (b) muscle contraction continues for long periods after

nervous stimulation ceases (c) the crossbridge bind to the actin and shorten the sarcomeres

(d) dystrophin is not needed to strengthen the contracting muscle cell (e) none of the above

17. When a nervous impulse travel from a neuron to a muscle cell, what happens next? (a) the

impulse travels over the sarcolemma in all directions. (b) Calcium is released from the

sarcoplasmic reticulum (c) linkages form between the actin and myosin (d) Acetylcholine is

decomposed by acetylcholinesterase (e) none of the above

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18. The type of muscle found in the irises of the eyes and in the blood vessels is called ___

(a) visceral smooth muscle (b) multiunit smooth muscle (c) cardiac muscle (d) skeletal

muscle (e) all the above

19. Which of the following does not belong with the others?

(a) multinucleated (b) skeletal (c) striated (d) involuntary

20. Each muscle fiber is directly surrounded by connective tissue called the ___

(a) perimysium (b) fascia (c) endomysium (d) epimysium (e) a and b

21. Which term is the smallest subdivision in this group?

(a) fiber (b) actin (c) filament (d) fibril

22. Which description of muscle contraction means that all of the fibers within a muscle are

fully contracted?

(a) all-on-one law (b) summation (c) titanic (d) muscle twitching (e) all of the above

23. The term __ refers to the constant state of contraction of a certain number of fibers

within a muscle.

(a) atrophy (b) hypertrophy (c) summation (d) tone (e) hyperplasia

24. Muscles that are not used may degenerate or undergo a process of ___

(a) atrophy (b) hypertrophy (c) fatigue (d) cetany (e) all of the above

25. Which of the following characterizes both skeletal and smooth muscle cells? (a) voluntary

control (b) multinucleated (c) striated (d) excitable (e) none of these answers

26. which list of muscle structures proceeds from smaller to larger in diameter? (a)

myofilament muscle, muscle fiber, myofibril (b) fascicle, myofibril, muscle fiber,

myofilaments (c) myofilament, myofibril, muscle fiber, fascicle (d) myofibril, fascicle,

muscle fiber, myofilament (e) a and b

27. Interactions between thick and thin filaments during muscle contraction occur in which

sequence?

(a) attach, detach, pivot, return (b) attach, pivot, detach, return (c) detach, pivot, return,

attach (d) pivot, attach, detach, return (e) all of these

28. What actually shortens when a muscle fiber contracts?

(a) thick and thin filaments (b) A bands, M lines and 2 discs (c) sarcomeres, H zones, and I

bands (d) both b and c (e) none of theses

29. Riger Motis demonstrates that skeletal muscle tissue

(a) normally requires energy to end as well as to start a contraction (b) can survive and

function for some time after the heart stops beating. (c) maintaining powerful contractions

even with no ATP, until autolysis occurs (d) a, b and c (e) none of these

30. Z discs are to skeletal muscle as ___ are to smooth muscle

(a) myofilaments (b) sarcomeres (c) transverse tubules (d) dense bodies (e) all of these

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31. A neuron:

(a) is the basic unit of the nervous system (b) is a nerve cell. (c) operates by generating

electrical signals (d) may communicate with other neurons via chemical signals (e) is

described by all of the above

32. The equilibrium potential:

(a) of a given ion across a membrane is a function of the concentration of that ion on both

sides of the membrane (b) of a given ion across a membrane is the potential at which there is

not net movement of that ion across the membrane due to electrochemical forces (c) of K

across a typical nerve cell membrane is close to the resting potential of most nerve cell (d) a

and b (e) a, b and c

33. Threshold stimuli are those which are strong enough to:

(a) repolarize the neuron membrane (b) cause a net flux of positively charged ions from

inside to outside the cell (c) cause a net flux of positively charged ions from outside to inside

the cell (d) close potassium channels to the point that an action potential is initiated (e) open

potassium channels to the point that an action potential is initiated.

34. During an action potential,

(a) voltage-gated Na

channels in the membrane open in response to depolarization (b)

Ligand-gated K

channels in the membrane open in response to neurotransmitter released

from adjacent membrane (c) the increase in Na

permeability in the membrane is an example

of positive feedback, (d) a and c (e) a, b and c

35. which of the following statements concerning the propagation of action potential is NOT

correct?

(a) Epitatory conduction occurs in myelinated nerve fiber (b) during conduction of an action

potential, current flows from the active area of the membrane ot the adjacent inactive area,

thereby decreasing the potential in the inactive area to the threshold (c) Action potential

propagation is faster in myelinated fibers than in unmyelinated ones (d) Action potential

propagation is faster in large-diameter fibers than in small-diameter ones (e) Action potential

propagation is faster for strong stimuli than for weaker stimuli

36. Parasymptic potential:

(a) directly result from the opening of voltage-gated ion channels (b) may be depolarizing or

hyperpolarizing (c) may be summed (d) b and c (e) a, b and c

37. An EPSP is:

(a) a type of graded potential (b) caused by an increase in the permeability of the

postsymnatic membrane to all small ions (c) hyperpolarizing (d) sufficient by itself to

generate an action potential (e) all-or-none in character.

38. An IPSP is:

(a) depolarizing (b) caused by an increase in the permeability of the postsynaptic membrane

to K

and/or Cl

to Na

(d) caused by an increase in the permeability of the postsynaptic membrane to all

small ions (e) described by none of the above.

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39. The blood brain barrier:

(a) functions to control the exchange of substances between blood and the extracellular fluid

in the CNS (b) is comprised of the cells that line the largest blood vessels In the brain (c) is

comprised of the cells that line the smallest blood vessel in the brain (d) a and c (e) a, b, and c

40. The somatic motor portion of the peripheral nervous system:

(a) contains efferent fibers (b) has cell bodies located in the brainstem only (c) have large

diameter myelinated axons (d) use acetylcholine as their neurotransmitter (e) a and c and d

41. Glial cells of the neural tissue: (a)are more abundant that neurons (b) respond to injury (c)

help myelinate CNS axons (d) help regulate neuronal environment (e) all of the above

42. Accessory digestive organs include:

(a) the pharynx (b) the gallbladder (c) the esophagus (d) the large intestine (e) the small

intestine

43. Nervous control of the GI tract would be impaired by damage to the

(a) mucosa (b) muscularis (c) submucosa (d) serosa (e) a and b

44. Myelin sheaths on the outside of many axons are contributed by ____

(a) the axon itself (b) secretory vesicles (c) Schwann cells (d) the cell bodies of the neuron (e)

sarcoplasm

45. A neuron with many nerve fibers arising from its cell body and that carries impulses away

from the brain would be classified as ___

(a) multipolar (b) bipolar (c) unipolar and sensory (d) mesenchymal cells

46. The ____ are the types of neuroglial cells that provide myelin in the central nervous

system.

(a) astrocytes (b) oligodendrocytes (c) microglia (d) ependyma (e) mesenchymal cells

47. The cells that conduct messages towards the brain are the:

(a) motor neurons (b) sensory neurons (c) interneurons (d) neuroglia (e) none of these

48. Which selection includes only accessory digestive organs?

(a) salivary glands, thyroid gland, pancreas, liver (b) stomach, duodenum, pancreas,

gallbladder (c) gallbladder, liver, pancreas, salivary glands (D) liver, thyroid gland,

gallbladder, spleen.

49. Movements in the small intestine that churn the materials being digested and mix them

with intestinal secretions are called

(a) peristalsis (b) pendular motility (c) segmentation (d) haustral churning (e) none of the

above

50. Which term describes the wave of muscular contraction that moves material through the

GI tract toward the anus?

(a) peristalsis (b) pendular motility (c) segmentation (d) haustral churning (e) all of the above

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51. The three pairs of multicellular salivary glands that secrete into the oral cavity are the ___

glands

(a) alpha, beta and gamma (b) parotid, submandibular, and sublingual (c) palatine, lingual

and pharyngeal (d) serous, mucous and mixed (e) a and d

52. From deep to superficial, what are the tunics of the intraperitoneal portions of the GI

tract?

(a) serosa, muscularis, submucosa, and mucosa (b) mucosa, submucosa, muscularis, and

serosa (c) adventitia, muscularis, submucosa, and mucosa (d) mucosa, submucosa,

muscularis, and adventitia

53. Within the mucous membrane of the GI tract, the layer of areolar connective tissue is

called the

(a) mucosal lining (b) lamina propria (c) muscularis mucosae (d) submucosa (e)all of the

above

54. Which list proceeds from the superior to the inferior end of the stomach?

(a) pylorus, fungus, cardia, body (b) cardia, body, fundus, pylorus (c) cardiac, fundus, body,

pylorus (d) body, cardia, pylorus, fundus

55. What is the function of the villi in the small intestine?

(a) to decrease the amount of exposed surface (b) to facilitate enzyme retention and dispersal

surface with wavelike actions (e) none of the above.

56. Which sequence lists the regions of the large intestine in order, from the end of the ileum

to the anus?

(a) cecum, rectum, anal canal, colon (b) colon, rectum, anal canal, cecum (c) cecum, colon,

rectum, anal canal (d) colon, cecum, rectum, anal canal

57. Which hormone stimulates the production of pancreatic juice and bicarbonate?

(a) aniotensin and apinephrine (b) gastrin and insulin (c) cholecystokinin and secretin (d)

insulin and glucagon (e) none of the above

58. Age-related changes in the digestive system include which of the following?

(a) reduced secretion of mucin, enzymes and acid (b) decreased replacement of epithelial

cells (c) diminished muscular tone and GI tract motility (d) all of the above (e) none of the

above.

59. Pepsin would be missing from the stomach contents of a person lacking

(a) chief cells (b) enterochromaffin-like cells (c) goblet cells (d) parietal cells (e) a and b

60. Inhibiting the secretion of cholecystokinin would

(a) stimulate gastric motility (b) stimulate gallbladder contraction (c) stimulate pancreatic

enzyme secretion (d) stimulate HCl secretion by parietal cells (e) a and b

61. Gastric acid secretion during the intestinal phase.

(a) is stimulated by vagal stimulation (b) is inhibited by fat in the chime (c) is stimulated by

gastrin secretion (d) is stimulated by amino acids in the stomach (e) none of the above

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62. Which of the following is NOT involved in swallowing?

(a) contracture of the upper esophageal sphincter (b) coordination by the swallowing center

in the medulla oblongata (c) the approximation of the vocal cords to close the glottis. (d) the

raising of the larynx to close its entrance. (e) the elevation of the soft palate to close the

nasopharynx

63. Emptying gastric contents into the small intestine is strictly controlled. Which of the

following is most accurately represent the concept?

(a) high caloric meals empty faster. (b) Liquid and solid meals empty at the same rate. (c)

higher acidity in the stomach results in a slower rate of emptying (d) tonicity of the gastric

solution doesn’t affect the rate of emptying (e) none of the above

64. Which of the following best describes type of saliva produced when parasympathetic

stimulation increases the rate of salivary secretion?

(a) corpius, protein-poor, electrolye-rich, (b) scant, transient, protein-rich(mucin), electrolyte

poor (c) scant, protein-poor, electrolyte-poor (d) coplus, protein-rich(mucin), electrolyte-rich

(e) c and d

65. which of the following transport processes is involved if transport of glucose from the

intestinal lumen into the small intestinal cell is inhibited by abolishing the usual Na

gradient

across the cell membrane?

(a) simple diffusion (b) facilitated diffusion (c) primary active transport (d) cotransport (e)

counter transport

66. During pulmonary circulation, blood leaves the

(a) right atrium and goes directly to the lungs (b)left ventricle and moves to the lungs (c)

right ventricle and goes to the aorta (d) right atrium and goes directly to the left ventricle (e)

left ventricle and moves to the lungs.

67. During systemic circulation, blood leaves the:

(a) right ventricle and moves to the lungs (b) lungs and move to the left atrium (c) right

atrium and goes directly to the lungs (d) right ventricle and goes directly to the aorta (e) left

ventricle and goes directly to the aorta.

68. The coronary arteries arise from the

(a) aorta (b) superior vena cava (c) inferior vena cava (d) pulmonary trunk (e) right atrium

69. the endothelium is composed of

(a) simple columnar epithelium (b) simple cuboidal epithelium (c) stratified squamous

epithelium (d) tunica media muscle cells (e) simple squamous epithelium

70. The inferior vena cava brings blood from the lowest regions of the body and empties in to

the:

(a) right atrium (b) right ventricle (c) left ventricle (d) aorta (e) left atrium

71. Which is correct sequence of layers in the vessel wall from outside to inside?

(a) tunica interna, tunica externa, tunica media (b) tunica media, tunica interna, tunica

externa (c) it varies from vessel to vesssel (d) tunica interna, tunical externa, tunica media (d)

tunica interna, tunica externa, tunica media (e) Tunica externa, tunica media, tunica interna

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72. Which of the following is the major force generating blood flow?

(a) blood-viscosity (b) peripheral resistance (c) blood vessel diameter (d) pumping action of

the heart (e) total blood vessel length

73. The major long-term mechanism of blood pressure control is provided by the

(a) the digestive tract (b) kidneys (c) the heart (d) paravertebral ganglia (e) the lungs

74. Blood enters the myocardium of the heart by coronal vessels that originate from the

(a) the pulmonary artery, (b) the inside of the ventrides (c) the superior vena cava (d) the

pulmonary veins (e)aorta

75. Exchange of gases and nutrients occurs by diffusion between the

(a) carpilaries and tissue cells (b) artery walls and tissue blood cells (c) arterioles and venules

(d) arterioles and tissue cells (e) arteries and veins

76. Any condition in which blood vessels are inadequately filled and blood cannot circulate

normally Is called

(a) arteriosclerosis (b) hypertension (c) atherosclerosis (d) varicose veins (e) circulatory

shock

77. Reduction in lumen diameter of a blood vessel as the smooth muscle contracts is known

(a) arteriosclerosis (b) vasodilation (c) atherosclerosis (d) varicose veins (e) vasoconstriction

78. which of the following regulates blood flow at the entrance to each true capillary?

(a) lymp nodes (b) tunica externa (c) tunica interna (d) precapilary sphincter (e) valves

79. loss of vasomotor tone resulting in a huge drop in peripheral resistance is known as

(a) vascular shock (b) vasoconstriction (c) atherosclerosis (d) hypertension (e) varicose veins

80. which of the following arteries branches to form the common hepatic artery, left gastric

artery, and splenic artery?

(a) Gonadal arteries (b) inferior mesenteric artery (c) descending aorta (d) superior

messentric artery (e) celiac trunck

81. The atrioventricular (AV) valves

(a) are located between the atria and the vena cava (b) are located between the ventricles and

the aorta (c) are located between the ventricles and the atria (d) are located within coronary

arteries (e) none of the above

82. The semilunar valves

(a) prevent the backward flow of blood from the ventricles into the atria (b) are open during

the relaxation phase of the ventricles. (c) are closed throughout the cardiac cycle (d) regulate

the passage of blood from the ventricles into the pulmonary artery and the aorta. (e) all of the

above

83. The __ is the normal pacemaker of the heart

(a)AV bundle (b) left atrium (c) right atrium (d) SA node (e) a and b

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84. An important function of the AV node is to

(a) rapidly transmit action potentials to the surface of the atria (b) delay the conduction of the

action potential from the atria to the ventricles (c) serve as a conduit for rapid transmission of

action potential to blood vessels (d) serve as a pacemaker for the contraction of cardiac

muscle. (e) all of the above.

85. An ECG measures

(a) The electrical activity of the heart (b) the entire cardiac output (c) The cardiovascular

flow rate (d) the cardiac glucose exportation (e) c and d

86. In the ECG to the right, what event(s) in the heart occur during the P wave?

(a) ventricles contract (b) ventricles relax (c) atria contract (d) atria relax (e) c and d

87. What type of tissue forms tendons?

(a) Elastic cartilage (b) dense irregular (c) areolar (d) Adipose (e) Dense regular

88. Goblet cells are associated with which of the following epithelial tissues?

(a) simple squamous (b) stratified squamous (c) stratified cuboidal (d) transitional (e) simple

columnar

89. The basement membrane is located between which of the following tissue types?

(a) Connective and muscle (b) Muscle and nervous (c) Epithelial and connective (d)

Epithelial and muscle (e) Nervous and connective

90. Which of the following apical epithelial cell structures functions in the movement of

material across the surface of the cell?

(a) Flagellum (b) basal body (c) Cilia (d) Microvilli (e) keratin

91. Which of the following epithelial tissue types is best adapted for the rapid transport of

materials across its membranes

(a) Pseudostratified ciliated columnar (b) Stratified squamous (c) Simple squamous (d)

Stratified cuboidal (e) Transitional

92. Which of the following is NOT a function of areolar connective tissue?

(a) Storing nutrients as fat (b) Holding body fluids (c) Support and binding of other tissues

(d) Movement of body parts (e) Defending the body against infection

93. The fibrous protein abundant in dense connective tissue is:

(a) insulin (b) cartilage (c) collagen (d) dentin (e) a and b

94. The skin is considered an organ because it

(a) produces pigments (b) is composed of at least two tissues (c) protects the body (d) allows

the body to detect sensory stimuli (e) all of the above

95. Adipose tissue is a type of

(a) cartilage (b) endoplasmic reticulum (c) connective tissue (d) blood (e) epithelial tissue

96. blood helps to maintain homeostasis by

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(a) transporting materials between the tissue fluid and the external environment (b) ridding

the body of wastes (c) breaking down nutrients (d) coordinating metabolic reactions (e) none

of the above

97. Low blood osmolarity

(a) causes the blood to absorb excess tissue fluid as it passes through the carpillaries (b) could

lead to increased blood volume and increased blood pressure (c) allows too much fluid to

remain in the tissues and leads to edema (d) could be caused by increased plasma protein or

sodium levels (e) all of the above

98. If you have some blood from which the formed elements have been removed, how can

you tell if it is plasma or serum?

(a) plasma contains hemoglobin, serum does not (b) serum is yellow; plasma has no color (c)

serum contains antibodies; plasma does not (d) plasma contains dotting proteins; serum does

not (e) a and b

99. Which leukocyte is NOT correctly matched with its description?

(a) eosinophyl-bilobed nucleus, deep red granules (b) lymphocyte-smallest leukocytes, round

nucleus, thin rim of cytoplasm (c) neutrophil-lobed nucleus with two to five segments, light

purple granules (d) basophil-typical kidney-shaped nucleus, largest white blood cell

100. What kind of risk adults when a woman who is Rh

carries an Rh

fetus?

(a) there is usually no risk during the first pregnancy, but it can harm the fetus during a

subsequent pregnancy if the mother is not treated (b) it always poses a serious risk to the

fetus, even in the first pregnancy (c) Only in rare cases is there a risk to the fetus during the

first pregnancy (d) there is never a risk to the fetus in any pregnancy (e) none of the above.

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