Physiology I & II Flashcards Preview

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Flashcards in Physiology I & II Deck (183):
1

________ refers to the maintenance of nearly constant conditions in the internal environment and is the condition in which the body's internal environment remains relatively constant within limits

Homeostasis

2

What are the 3 primary characteristics of the internal environment of an organism in homeostasis?

Contains optimum concentration of gases, nutrients, ions, water

Has optimal temperature

Has optimal pressure for health of cells

3

_______ is any stimulus that creates an imbalance in the internal environment

Stress

4

What type of feedback loop is defined by a response that reverses the direction of the initial condition?

Negative feedback loop

5

What are the 2 primary characteristics of negative feedback loops?

-Diminishes original change
-Stabilizing

6

What are the 2 primary characteristics of positive feedback loops?

Enhances original change
Destabilizing (can lead to runaway effects)

7

The stretch of the cervix during delivery sends signals that increase the force of uterine contractions which then increase the stretch on the cervix. This is an example of what type of feedback loop?

Positive

8

Baroreceptors are stretch receptors associated with the carotid system. When these sense an increase in arterial pressure, they send inhibitory signals to vasomotor receptors in the medulla. Heart pumping capacity is reduced and blood vessels dilate, leading to a decrease in arterial pressure. This is an example of what type of feedback loop?

Negative

9

An increase in the production of TSH releasing factor results in an increase in the release of TSH, which results in the release of more thyroxine, which results in a decrease in the production of TSH releasing factor. This is an example of what type of feedback loop?

Negative

10

______ is the degree of effectiveness with which a control system maintains constant conditions

Gain

11

How is gain calculated?

Correction/error

12

Adding 2 L of blood to an uncontrolled system and to a controlled system:

Uncontrolled system: Pressure rises from 100 to 175
Controlled system: Pressure rises from 100 to 125

Calculate the gain in this case.

Gain = Correction/Error = -50/25

Answer: -2

13

Baroreceptors (pressure receptors) in the carotid system sense changes (increases) in the arterial pressure. These baroreceptors send signals to the brainstem where the cardiac centers are located. A feedback system then activates a number of responses that result in a lowering of arterial presure. Two dogs are used in a study to test the effects of a drug that causes hypertension as a possible side effect. In one of the dogs the baroreceptor feedback system has been inactivated. In the dog with the intact feedback system, the arterial pressure increases from 100 to 110. In the animal with the inactivated control system, the pressure increases from 100 to 150. What is the effectiveness with which the baroreceptor system controls increase in blood pressure?

A. -1
B. -2
C. -4
D. -5

C. -4

14

The Na+/K+ ATPase pump utilizes energy derived directly from the breakdown of ATP. What type of transport is this?

Primary active transport

15

The Na+-Glucose co-transporter utilizes energy derived secondarily from concentration differences of molecular ionic substances created originally by primary active transport. What type of transport is this?

Secondary active transport

16

What is the most common cation in the extracellular environment?

Sodium

17

What is the most common cation in the intracellular environment?

Potassium

18

How is speed of action potential transmission affected by axon diameter and myelination?

Small diameter axons transmit more slowly than large diameter

Myelinated axons transmit more rapidle than non-myelinated

19

What type of action potential conduction requires myelination and is characteristic of the axon but not the cell body or dendrites?

Saltatory conduction

20

During skeletal muscle contraction, what specific event directly follows the opening of ligand-gated sodium channels in response to Ach binding?

Influx of sodium leads to end-plate depolarization (EPP)

21

During skeletal muscle contraction, what specific event directly follows the opening of voltage-gated sodium channels?

Sarcolemma action potential

22

Which band of skeletal muscle is formed by actin filaments and becomes narrower in width during contraction?

I band

23

Which band of skeletal muscle is equivalent to the length of the myosin filaments and does not change width during contraction?

A band

24

Which band of skeletal muscle is the part of the A band that is not overlapped by actin filaments and becomes narrower during contraction?

H band

25

Compare skeletal muscle fibers to cardiac muscle fibers in terms of nucleation

Skeletal = multinucleated, peripheral nuclei

Cardiac = central, single nucleus

26

Compare skeletal muscle fibers to cardiac muscle fibers in terms of arrangement

Both have sarcomeric arrangement

27

Compare skeletal muscle fibers to cardiac muscle fibers in terms of locations of T tubules

Skeletal: T tubules are found at the ends of thick filaments

Cardiac: T tubules are found along the Z line

28

Compare skeletal muscle fibers to cardiac muscle fibers in terms of number of cisternae per T tubule

Skeletal: 2 cisternae/T tubule

Cardiac: 1 cisternae/T tubule

29

In skeletal muscle fibers, T tubules form ______ with the sarcoplasmic reticulum. In cardiac muscle fibers, T tubules form ______ with the sarcoplasmic reticulum.

Triads
Dyads

30

Do skeletal muscle fibers or cardiac muscle fibers have a more extensive sarcoplasmic reticulum?

Skeletal muscle fibers

31

Describe the arrangment of muscle fibers in skeletal muscle fibers vs. cardiac muscle fibers

Skeletal: motor unit arrangement (one nerve fiber synapses with multiple muscle fibers)

Cardiac: muscle cells form syncytium

32

Which of the following utilize DHP channels on T-tubules and Ryanodine receptors on the sarcoplasmic reticulum?

A. Skeletal muscle fibers
B. Cardiac muscle fibers
C. A and B are correct
D. None of the above

C. A and B are correct

33

Which phase (1-4) of a fast cardiac muscle action potential is considered the resting potential, and what is this resting potential?

Phase 4 is the resting potential = -85 mV

34

What are the 4 phases of fast cardiac action potentials?

Phase 4: Resting potential (-85 mV)
Phase 0: Rapid depolarization
Phase 1: Initial, incomplete repolarization
Phase 2: Plateau or slow decline of potential
Phase 3: Repolarization

35

Fast cardiac action potentials have:

________ AP amplitude
More _______ rate of rise of phase 0
_________ cell diameter

Greater
Rapid
Larger

36

Do slow cardiac muscle action potentials have fast sodium gates?

No

37

The upstroke of SLOW cardiac action potentials is due to _________, so it proceeds slowly. The resting phase potential 4 is close to ______ mV rather than -90 mV characteristic of fast APs. The overall change in potential (amplitude) is _______ compared to fast action potentials. SA and AV nodal tissue will spontaneously depolarize to reach phase ____

Calcium
-60
Less
4 (resting)

38

The force of contraction and stroke volume are related to the _______, which is the amount of blood left in the ventricle just before it contracts at the end of diastole

End diastolic volume (EDV)

39

The force of contraction is related to ______ which is the actual amount of blood that is ejected from the heart.

Stroke volume (SV)

40

How is stroke volume calculated?

EDV - ESV

41

Force of contraction and stroke volume are related to ____ which is the amount of blood left after contraction

End systolic volume (ESV)

42

What is ejection fraction and how is it calculated?

EF is the amount of blood capable of being ejected

EF = SV/EDV [will need to calculate on exam - on slide the answer is 70/110=64%]

43

Stroke volume can be increased to more than double by increasing _______ and/or decreasing _______

EDV
ESV

44

On a normal ECG, depolarization is represented by which waves?

P and QRS

45

Of the depolarization waves on the ECG, what wave refers to atrial depolarization?

P wave

46

Of the depolarization waves on an ECG, what wave refers to ventricular depolarization?

QRS

47

What represents the repolarization wave on a normal ECG?

T wave - ventricular repolarization

48

On ECG vectors, where are the 2 electrodes placed for the axis for bipolar lead I? What is the direction of the lead?

2 electrodes on 2 arms

R=negative
L=positive

Direction of the lead = 0 degrees

49

On ECG vectors, where are the 2 electrodes placed for the axis for bipolar lead II? What is the direction of the lead?

Electrodes on R arm and L leg

R Arm = negative
L Leg = positive

Direction of the lead = 60 degrees

50

On ECG vectors, where are the 2 electrodes placed for the axis for bipolar lead III? What is the direction of the lead?

Electrodes on L arm and L leg

L arm = negative
L leg = positive

Direction of the lead = 120 degrees

51

What is the primary characteristic on an ECG representing a sinoatrial nodal block?

P wave is absent

52

Blood pressure varies in different parts of the circulatory system. The pressure begins at ______ mm Hg in the aorta and decreases to ____ mm Hg once it reaches the venous system

120
0

[so a total loss of 120 mm Hg from the heart to the venous sytem]

53

In terms of blood distribution, the majority of blood volume overall is in systemic circulation (84%). The majority of the blood in systemic circulation at 64% is in which of the following?

A. Veins
B. Arteries
C. Arterioles
D. Capillaries

A. Veins

54

A systemic vein is about 8x as distensible as its corresponding artery and has a volume of about 3x as great. How would its compliance compare to that of a corresponding artery?

The systemic vein is 24x more compliant than the artery

55

What is another term for vascular compliance?

Capacitance

56

Vascular compliance/capacitance tells us the total quantity of blood that can be stored in a given portion of the circulation for each mm Hg rise in pressure. How is compliance calculated?

Increase in volume/increase in pressure

[note direct relationship to volume and indirect relationship to pressure]

57

Factors that affect venous return to the heart from the systemic circulation involve the degree of filling of systemic circulation. When heart pumping stops, all blood flow ceases. Pressures in everywhere in the body become equal, this is known as what type of pressure?

Mean circulatory filling pressure

58

When the blood volume is 4 L, what is the mean circulatory filling pressure?

0 mm Hg

59

When the blood volume is 5 L, what is the mean circulatory filling pressure?

7 mm Hg

60

The mean circulatory filling pressure is almost equal to what pressure?

The mean systemic filling pressure

61

Resistance to blood flow affects venous return to the heart from systemic circulation. When the venous return is 5 L/min, mean systemic filling pressure is 7 mm Hg, and the right atrial pressure is 0 mm Hg, what is the resistance to venous return?

1.4 mm Hg per L/min of blood flow


[these are the normal parameters]

62

The kidneys receive about what percentage of total cardiac output?

22%

63

What is the main driving force for filtration in the kidneys?

Hydrostatic pressure


This is high in glomerular capillaries (rapid filtration) and low in peritubular capillaries (rapid reabsorption)

64

Glomerular filtration rate is determined by what 2 forces acting across the capillary membrane?

Hydrostatic forces
Colloid osmotic forces



[the capillary filtration coefficient is the product of permeability and filtering surface area of capillaries]

65

What is the average glomerular filtration rate (GFR) in ml/min and in L/day?

125 ml/min

180 L/day

66

Which of the following has the greatest effect on increasing GFR?

A. Bowman's capsule hydrostatic pressure
B. Glomerular capillary colloid osmotic pressure
C. Glomerular hydrostatic pressure
D. Colloid osmotic pressure of Bowman's capsule

C. Glomerular hydrostatic pressure

67

Which kidney tubule is responsible for reabsorption of 65% of filtered sodium, chloride, bicarbonate, and potassium?

PCT

68

The proximal tubule of the kidney reabsorbs all filtered glucose and amino acids using WHAT type of transport via WHAT transporter?

Secondary active transport
Sodium/glucose cotransporter

69

What is the source of Aldosterone?

Adrenal cortex

70

What is the major site of action of Aldosterone? What type of transporter is used?

Principle cells of cortical collecting ducts using Na+/K+ ATPase pump

71

Aldosterone increases _______ reabsorption and stimulates ______ secretion

Na+
K+

72

The late distal tubule/cortical collecting tubule of the kidney utilizes __________ cells to reabsorb ____ from the tubular lumen and secrete _____ into tubular lumen

Intercalated
K+
H+

73

What buffer system plays a major role in buffering renal tubular fluid and intracellular fluids?

Phosphate buffer system

74

An increase in plasma bicarbonate ion is due to addition of new bicarbonate by the kidney is the primary compensatory response to which of the following?

A. Metabolic acidosis
B. Metabolic alkalosis
C. Respiratory acidosis
D. Respiratory alkalosis

C. Respiratory acidosis

75

An increased ventilation rate and renal compensation by adding new bicarbonate ion to ECF are the primary compensatory responses to which of the following?

A. Metabolic acidosis
B. Metabolic alkalosis
C. Respiratory acidosis
D. Respiratory alkalosis

A. Metabolic acidosis

76

Alkalosis results from an increase in ratio of bicarbonate to hydrogen ion concentration. What are the general compensatory mechanisms in terms of the kidneys?

Excess bicarb is excreted in urine resulting in H+ ions added to ECF

77

A reduction in plasma bicarbonate ion concentration caused by renal excretion of bicarbonate ion is the compensatory response associated with which of the following?

A. Metabolic acidosis
B. Metabolic alkalosis
C. Respiratory acidosis
D. Respiratory alkalosis

D. Respiratory alkalosis

78

Decreased ventilation and increased renal bicarbonate ion excretion are compensatory responses associated with which of the following?

A. Metabolic acidosis
B. Metabolic alkalosis
C. Respiratory acidosis
D. Respiratory alkalosis

B. Metabolic alkalosis

79

A decrease in carbon dioxide concentration caused by hyperventilation is characterized by which of the following?

A. Metabolic acidosis
B. Metabolic alkalosis
C. Respiratory acidosis
D. Respiratory alkalosis

D. Respiratory alkalosis

80

A rise in ECF bicarbonate ion concentration is characteristic of which of the following?

A. Metabolic acidosis
B. Metabolic alkalosis
C. Respiratory acidosis
D. Respiratory alkalosis

B. Metabolic alkalosis

81

_______ ______ ______ refers to the maximum volume of gas the lungs can hold

Total lung capacity

82

________ volume refers to the volume of air that is inspired or expired with each breath at rest

Tidal

83

_________ _______ volume refers to the volumem of air that can be inspired in addition to tidal volume with forceful inspiration

Inspiratory reserve

84

_______ volume refers to the volume of air remaining in lungs after forceful expiration (this volume cannot be eliminated no matter how hard you breathe out)

Residual

85

_______ _______ refers to the sum of all the volumes that can be inspired or exhaled

Vital capacity

86

How is total lung capacity calculated?

Vital capacity + Residual volume

87

_________ capacity is the sum of volumes above resting capacity, so it equals tidal volume + inspiratory reserve volume

Inspiratory

88

What pulmonary capacity is calculated by the sum of volumes below resting capacity, so expiratory reserve volume + residual volume

Functional residual capacity

89

There are several pressures resulting in movement of air in and out of the lungs. ______________ pressure refers to the difference between the alveolar pressure and the pleural pressure

Transpulmonary

90

The ventilation-perfusion ratio Va/Q is related to pulmonary gas exchange. What do these variables stand for?

Va = alveolar ventilation
Q = pulmonary capillary blood flow

91

As you breathe in atmospheric air, the air is humidified by your lungs - thus adding gas to existing gas. Because this gas is added, partial pressures of atmospheric gases are ____________ (increased/reduced)

Reduced

92

The utilization coefficient is the percentage of blood that gives up its oxygen. What is the average utilization coefficient?

25% (5 ml O2 per dl/19.4 ml O2)


This value increases with strenuous exercise to 75-85%

93

About 70% of carbon dioxide in the body is transported as ______________

Bicarbonate

94

What are the 2 primary respiratory centers in the brain?

Dorsal respiratory group
Pontine respiratory group

95

What respiratory center in the brain is responsible for establishing ramp signal?

Dorsal respiratory group

96

What respiratory center in the brain is responsible for controlling the rate and depth of breathing?

The pneumotaxic center, which is a part of the pontine respiratory group

97

Which of the following types of neurons would transmit an action potential the fastest?

A. Small diameter, non-myelinated
B. Small diameter, myelinated
C. Large diameter, myelinated
D. Large diameter, non-myelinated

C. Large diameter, myelinated

98

Saltatory conduction is characteristic of which part of a typical neuron?

A. Dendrite
B. Nerve cell body
C. Axon hillock
D. Axon

D. Axon

99

The resting potential for a typical neuron, such as a motor neuron, is best represented by which of the following potentials?

A. 74 mV
B. -74 mV
C. 90 mV
D. -90 mV

D. -90 mV

100

Which of the following represents the first thing that happens after Ach binds to ligand-gated ion channels on the sarcolemma?

A. An action potential is created on the sarcolemma
B. Dihydropyridine channels allow entry of calcium ions
C. An end plate potential is created on the muscle fiber
D. None of the above

C. An end plate potential is created on the muscle fiber

101

Which of the following characteristics would be true of cardiac muscle cells but not skeletal muscle fibers?

A. Sarcomeric banded pattern
B. Utilization of T tubules
C. Mononucleated
D. Utilization of ryanodine receptors

C. Mononucleated

102

Resting potential of -85 mV is characteristic of which of the following phases of the cardiac fast action potential?

A. Stage 1
B. Stage 2
C. Stage 3
D. Stage 4

D. Stage 4

103

Which of the following is responsible for the plateau that characteries a cardiac muscle action potential?

A. High concentration of calcium ions in the intracellular fluid
B. High concentration of calcium ions in the extracellular fluid
C. High concentration of potassium ions in the intracellular fluid
D. High concentration of potassium ions in the extracellular fluid

A. High concentration of calcium ions in the intracellular fluid

104

The action potential for both a ventricular cardiomyocyte and purkinje fibers exhibits a plateau phase (1 and 2). Conductance of which ions is responsible for phase 0?

A. Calcium
B. Potassium
C. Sodium
D. Potassium and calcium

C. Sodium

105

Blood flow resistance is indirectly proportional to which of the following?

A. Viscosity
B. Vessel diameter
C. Density
D. A and C

B. Vessel diameter

106

Consider the following statements:

i. Veins are 8x more distensible than arteries
ii. Vascular compliance is directly proportional to volume increase and indirectly proportional to pressure

A. Only i is true
B. Only ii is true
C. Both are true
D. Both are false

C. Both are true

107

Which of the following properties refers to the ease with which hollow structures may be distended?

A. Elastence
B. Compliance
C. Resistance
D. Distensibility

B. Compliance

108

High resistance in which group of vessels results in the disappearance in phasic pressure pattern as seen in aorta?

A. Pulmonary arteries
B. Systemic arterioles
C. Systemic veins
D. Pulmonary capillaries

B. Systemic arterioles

109

Which of the following is the GFR in adult humans?

A. 3 L/day
B. 125 L/day
C. 180 L/day
D. 360 L/day

C. 180 L/day

110

How much of the cardiac output is received by the kidneys?

A. 25%
B. 50%
C. 75%
D. 100%

A. 25%

111

Which brain primordium contains:

Basal ganglia
Olfactory lobes+nerves
Cerebral hemispheres

Telencephalon

112

Which brain primordium contains:

Cerebral aqueduct of Sylvius
Superior and inferior colliculi
Tegmentum

Mesencephalon

113

Which brain primordium contains:

Epithalamus
Thalamus
Hypothalamus
Infundibulum

Diencephalon

114

Which brain primordium contains:

Cerebellum
Pons

Metencephalon

115

Which brain primordium contains:

Medulla oblongata
Posterior choroid plexus

Myelencephalon

116

Which primary cortical area maintains direct connections with specific muscles?

Primary motor areas

117

What is the function of the primary sensory areas?

Detect specific sensations

118

What is the action of secondary motor areas?

Provide patterns of motor activity

119

What is the action of secondary sensory areas?

Analyze the meanings of specific sensory signals

120

What are the 3 primary characteristics of tonic receptors?

Slow adapting
Detect continuous stimulus strength
Transmit impulses as long as stim. is present

121

What are the 2 primary examples of types of tonic receptors?

Muscle spindles
Golgi tendon organs

(Also macula, baroreceptors, chemoreceptors)

122

What system is also known as the posterior column system and carries sensations for 2-point sensation (fine touch), pressure, and vibration?

Medial lemniscus system

123

What nerve fiber type carries slow chronic pain, itch, temperature, and crude touch?

Group IV (type C fibers)

124

In the visual cycle, when rhodopsin is exposed to light energy, it goes through a series of steps to become what 2 products?

Scotopsin and all-trans retinal

125

Which type of ganglion cells have large diameter, transmit signals at 50 m/sec or faster, and respond to rapid changes in visual image?

Y ganglion cells

126

In terms of generating action potentials in hair cells, note that the high ____________ concentration of endolymph is related to the resting potential within the hair cells and the generation of an action potential. The inability of the ___________ ___________ to conduct potassium ions into the external fluid is the most common cause of congenital deafness.

Potassium
Stria vascularis

127

Muscle spindles consist of 3-12 intrafusal fibers and detect changes in muscle length. These are innervated by what type of neurons?

Small gamma motor neurons

128

The pyramidal system consists of what two tracts?

Corticospinal tract
Corticobulbar tract

129

There are 4 pairs of cerebellar nuclei. 3 pairs go together: the dentate nuclei, emboliform nuclei, and globose nuclei. The 4th pair is important for postural activity and limb movements via the reticulospinal and vestibulospinal tracts, what is it?

Fastigial nuclei

130

What cell type provides the only output from the cerebellar cortex?

Purkinje cells

(These also have extensive dendritic branching, project to intracerebellar nuclei, and receive input from parallel fibers)

131

What component of the cerebellum consists of flocculonodular lobes and vermis? What would be the result of a loss of flocculonodular lobes?

Vestibulocerebellum; loss of flocculonodular lobes would lead to extreme disturbance of equilibrium and postural movements

132

What component of the cerebellum consists mostly of vermis and an intermediate zone?

Spinocerebellum

133

What component of the cerebellum consists of lateral parts of the hemispheres, and is mostly associated with premotor and the primary and association somatosensory areas of the cerebral cortex? It is involved in the coordination of skilled movement and speech

Cerebrocerebellum

134

What is the best known stimulus for increasing the rate of TSH secretion?

Cold

135

What are the primary physiological mechanisms that alter the critical set point for thermal control?

Skin temperature changes

136

True or false: slow waves are true action potentials

FALSE

137

How are slow wave activities generated? (What is the pacemaker for slow wave activity?)

Cells of Cajal undergo cyclic changes that periodically open and produce inward currents (pacemaker)

138

Interneurons of the myenteric plexus utilize ___________ as a neurotransmitter, thus individuals on certain medications may experience decreased GI motility

Serotonin

139

Gastrointestinal reflexes transmit signals long distance to other areas of the gut tract, and there are 3 types. Which type causes evacuation of the colon?

Gastrocolic reflex

140

Gastrointestinal reflexes transmit signals long distance to other areas of the gut tract, and there are 3 types. Which type inhibits stomach motility and secretion?

Enterogastric reflex

141

Gastrointestinal reflexes transmit signals long distance to other areas of the gut tract, and there are 3 types. Which type empties the ileal contents into the colon?

Colonoileal reflex

142

During HCl secretion, what type of ATPase mediates transport between the ECF and parietal cells?

K+/Na+ ATPase

143

During HCl secretion, what type of ATPase mediates transport between parietal cells and the lumen of canaliculus?

H+/K+ ATPase

144

What hormone is responsible for regulating pancreatic secretions?

Secretin

145

The release of secretin is stimulated by the presence of _______ foods in the upper intestine. It is secreted by the __________ and upper jejunal mucosal cells. Secretin stimulates the release of large amounts of ________ ________, which stimulates pancreatic bicarb secretion. Secretin also inhibits ________ acid secretion

Acidic
Duodenal
Sodium bicarb
Gastric

146

The liver has ________ blood flow and _____ vascular resistance

High
Low

147

Lipoproteins like VLDLs, LDLs, and HDLs transport lipids in the blood. Which of these has the highest concentration of cholesterol and a moderate concentration of phospholipids?

LDLs

148

During bilirubin formation, iron is transported in the blood by __________. Eventually, heme is converted by heme oxygenase into _____________, which is what gets converted into free (unconjugated) bilirubin.

Transferrin
Biliverdin

149

Triglycerides may be used as an energy source by which process?

Beta oxidation

150

Beta oxidation begins in the mitochondria. What is the carrier molecule for acetyl coA to be brought into the mitochondria?

Carnitine

151

What steps of the ornithine (urea) cycle take place in the mitochondria?

Ammonia + CO2 --> carbamoyl phosphate

Carbamoyl phosphate + ornithin --> citrulline

152

What effect does PTH have on bone?

Causes absorption of calcium and phosphate


(Note that osteoclasts do NOT have receptors for PTH, osteoblasts do which then recruit monocytes)

153

ANS pathways consist of 2 neurons in sequence: preganglionic and postganglionic. Describe preganglionic neurons in terms of cell body location, myelination, and NT's.

Cell bodies are located in CNS
Axons are myelinated
NT is ACh

154

ANS pathways consist of 2 neurons in sequence: preganglionic and postganglionic. Describe postganglionic neurons in terms of cell body location, myelination, and NT's.

Cell bodies are located in peripheral ganglia
Axons are not myelinated
NT is ACh in parasympathetic system and NE in sympathetic system

155

About 75% of all parasympathetic fibers are located in which nerve?

CN X: Vagus nerve

156

Both thecal cells and granulosa cells can release progesterone, but only granulosa cells contain ___________, allowing them to produce estrogen. Thecal cells secrete ___________.

Aromatase
Androgens

157

A sharp surge of _____ precedes ovulation by about 24 hours

LH

158

What cells produce testosterone?

Interstitial cells of leydig

159

What 3 reasons explain why the placenta is able to provide adequate oxygenation at such a low pressure gradient?

Fetal hemoglobin
Fetal blood hemoglobin concentration is about 50% greater than maternal
Bohr effect

160

Which of the following forms of spina bifida is characterized by only meninges in the sac?

A. Occulta
B. Meningocele
C. Myelomeningocele
D. Myeloschisis

B. Meningocele

161

When exposed to light, rhodopsin dissociates into which of the following?

A. Scotopsin and 11-cis retinal
B. Scotopsin and 11-cis retinol
C. Scotopsin and metarhodopsin
D. Scotopsin and all-trans retinal

D. Scotoposin and all-trans retinal

162

Which of the following is true regarding slow pain receptors?

A. Felt within .1 seconds after stimulus is applied
B. Part of the neospinothalamic tract
C. Carried by c type fibers
D. Fibers synapse and terminate in the thalamus

C. Carried by C type fibers

163

What is the primary function of the secondary motor areas of the cortex?

A. Directly connected to specific muscles
B. Detect specific sensations
C. Provide patterns of motor activity
D. Analyze meanings of specific sensory signals

C. Provide patterns of motor activity

164

Which of the following distinguishes tonic receptors from phasic receptors?

A. Tonic are fast adapting
B. Tonic detect discontinuous stimulus strength
C. Tonic transmits impulses as long as stimulus is absent
D. Tonic is slow adapting

D. Tonic is slow adapting

165

Which of the following is NOT an example of a tonic receptor?

A. Muscle spindles
B. Golgi tendon organs
C. Macula and vestibular receptors
D. Baroreceptors
E. Type C pain fibers

E. Type C pain fibers

166

Which ascending pathway carries sensations for 2-point sensation, pressure, and vibration?

A. Dorsal column medial lemniscal pathway
B. Ventral spinothalamic pathway
C. Anterolateral spinothalamic tract
D. Medial lemniscus system

D. Medial lemniscus system

167

Which nerve fibers carry slow, chronic pain, itch, temperature, and crude touch?

A. Group Ia (type A alpha)
B. Group Ib (type A alpha)
C. Group II (type A beta, gamma)
D. Group III (type A, delta)
E. Group IV (type C)

E. Group IV (type C)

168

Which set of ganglion cells make up 5% of all ganglion cells, large diameter, respond to rapid changes in visual image and apprise the CNS?

A. W ganglion cells
B. X ganglion cells
C. Y ganglion cells
D. Z ganglion cells
E. All of the above

C. Y ganglion cells

169

Which ion is associated with the most common cause of congenital deafness, resulting in the ability of the stria vascularis to conduct this ion into the external fluid?

A. Na+
B. Ca2+
C. K+
D. Cl-

C. K+

170

Which of the following ions in endolymph is related to the resting potential within the hair cells and the generation of an AP?

A. Sodium
B. Calcium
C. Potassium
D. Chloride

C. Potassium

171

Which of the following makes up the medullary pyramids?

A. Reticulospinal tract
B. Rubrospinal tract
C. Corticospinal tract
D. Vestibulospinal tract

C. Corticospinal tract

172

Which region of the cerebellum is the location for control functions for muscle movements of the axial body, neck, shoulders, and hips?

A. Vermis
B. Intermediate zone
C. Lateral zone
D. Cerebrocerebellum

A. Vermis

173

What is the function of the interstitial cells of Cajal?

A. Pacemaker activity for smooth muscle cells
B. Inhibition of stomach motility and secretion
C. Secretory activity of intestinal mucosa
D. Opening of K+ channels during intestinal contraction

A. Pacemaker activity for smooth muscle cells

174

Which ion is transported between the lumen and basal membrane (ATPase) in parietal cell secretion?

A. Sodium
B. Chloride
C. Potassium
D. Hydrogen

C. Potassium

175

A lesion to which of the following intracerebellar nuclei is responsible for trunk ataxia?

A. Dentate nuclei
B. Emboliform nuclei
C. Globose nuclei
D. Fastigial nuclei

D. Fastigial nuclei

176

Which of the following is the only output from the cortex?

A. Golgi type I cells
B. Purkinje cells
C. Basket cells
D. Stellate cells

B. Purkinje cells

177

Parietal cells are responsible for the secretion of HCl, what is the mode of transport for hydrogen ions being pumped out of the cell?

A. Sodium-chloride exchanger
B. Sodium-hydrogen exchanger
C. Potassium-hydrogen exchanger
D. Potassium-chloride exchanger

C. Potassium-hydrogen exchanger

178

Which cells of the male reproductive system form testosterone?

A. Sertoli cells
B. Glandular cells
C. Interstitial cells of Leydig
D. All of the above

C. Interstitial cells of Leydig

179

In the urea (ornithine) cycle, which of the following reaction occurs in the mitochondria?

A. Citrulline + aspartate --> argininosuccinate
B. Arginine ---> urea + ornithine
C. Ammonia + CO2 --> carbamoyl phosphate
D. Both A and C in the mitochondria

C. Ammonia + CO2 --> carbamoyl phosphate

180

Which of the following is the major rate-limiting factor for almost all energy metabolism of the body?

A. ATP
B. ADP
C. NAD+
D. Glucose

B. ADP

181

Which of the following is true?

A. The liver has a low blood flow and high vascular resistance
B. The liver has a low blood flow and low vascular resistance
C. The liver has high blood flow and high vascular resistance
D. The liver has high blood flow and low vascular resistance

D. The liver has high blood flow and low vascular resistance

182

Heme is released from damaged RBCs and is split into globin and heme by macrophages. Heme is then converted into which of the following by heme oxygenase?

A. Cholic acid
B. Biliverdin
C. Bilirubin
D. Urobilinogen

B. Biliverdin

183

Testosterone is able to be converted into estrogen by the action of which of the following?

A. Cholesterol
B. Aromatase
C. LH
D. FSH

B. Aromatase