1|Page
Actual exam for NBME Physiology 2025 update |
comprehensive questions and verified answers
(complete solutions) GRADE A+!!
**A result of the high resting conductance to K+ which drives the membrane potential toward the K+
equilibrium potential (-85 mV) - . . ANSWER ✓✓ Normal resting membrane potential?
-Beta-adrenergic receptors
-Epi/NE
-cAMP - . . ANSWER ✓✓ SNS salivary stimulation:
-Receptors?
-NT?
-2nd messenger?
-Muscarinic cholinergic receptors
-ACh
-IP3, and increased intracellular [Ca++] - . . ANSWER ✓✓ PNS salivary stimulation:
-Receptors?
-NT?
-2nd messenger?
**Decreased parasympathetic (vagal) outflow to the heart and increased sympathetic outflow to the
heart and blood vessels:
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1. Increased HR
2. Increased contractility and stroke volume
**Increased HR and SV together produce an increased CO, which increases arterial pressure.
3. Increased vasoconstriction of arterioles
4. Increased venoconstricition (veins) to increase venous return to the heart - . . ANSWER ✓✓
*Apneustic center* (lower pons): stimulates deep and prolonged inspiration.
*Pneumotaxic center* (upper pons): Inhibits inspiration - . . ANSWER ✓✓ What are the two Pontine
respiratory centers?
What are their functions?
*At rest*: sympathetic control is important (alpha-1 receptors = vasoconstriction; Beta-2 receptors=
vasodilation)
*During exercise*: Local metabolic control is most important (Lactate, K+, and adenosine INCREASE
blood flow to muscles) - . . ANSWER ✓✓ Most important mechanism of active hyperemia to the muscle
during rest? During exercise?
*Dorsal respiratory group*: responsible for normal inspiration and generates the basic rhythm for
breathing. (receives input from vagus and glossopharyngeal nerves)
*Ventral respiratory Group*: primarily responsible for expiration.
**Not active during normal breathing when expiration is passive; activated when expiration becomes an
active process. - . . ANSWER ✓✓ What are the two medullary respiratory centers?
What are their functions?
*Increase* blood flow
or
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*decrease* cross sectional area
**site of slowest blood velocity= capillaries due to having the largest total cross-sectional area. - . .
ANSWER ✓✓ Increase the velocity of blood flow by:
__________ blood flow
or
___________ cross-sectional area
*Increasing* the viscosity of blood
*Increasing* the length of the vessel
*Decreasing* the radius of the vessel
**Decreased radius Has a HUGE effect on increasing resistance. - . . ANSWER ✓✓ Resistance to blood
flow can be increased by:
__________ the viscosity of blood
___________ the length of the vessel
___________ the radius of the vessel
(Poiseuilles equation)
*Isometric* contraction
*Isotonic* contraction - . . ANSWER ✓✓ Contractions that are measured when *length* is held
constant?
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Contractions that are measured when *load* is held constant?
*Medium-sized bronchi*
**Not the smallest bronchi because of their parallel arrangement - . . ANSWER ✓✓ Bronchi with the
largest resistance in the airway?
*Pulsatile* GnRH release from the hypothalamus
**FSH and LH are secreted in a pulsatile fashion
**GnRH up regulates its own receptor in the anterior pituitary - . . ANSWER ✓✓ Puberty in males and
females is initiated by?
0 and 10 mmHg
**If 02 does not equilibrate between alveolar gas and arterial blood, then PA02 will be greater than
Pa02 - . . ANSWER ✓✓ Normal A-a gradient is in what range?
1 M CaCl2 because the conc. of particles is higher. - . . ANSWER ✓✓ Which has a higher osmotic
pressure: 1 M CaCl2 or 1 M KCl?
1. *INCREASED fiber size*: increased diameter= decreased internal resistance= increased conduction
velocity
2. *myelination*: allows for saltitiory conduction at nodes of Ranvier. - . . ANSWER ✓✓ What two things
increase conduction velocity in nerves?
1. *Increased HR*: more action potentials occurring per unit time= more intracellular Ca++ stored in the
SR= more Ca++ released from the SR= stronger contraction
Actual exam for NBME Physiology 2025 update |
comprehensive questions and verified answers
(complete solutions) GRADE A+!!
**A result of the high resting conductance to K+ which drives the membrane potential toward the K+
equilibrium potential (-85 mV) - . . ANSWER ✓✓ Normal resting membrane potential?
-Beta-adrenergic receptors
-Epi/NE
-cAMP - . . ANSWER ✓✓ SNS salivary stimulation:
-Receptors?
-NT?
-2nd messenger?
-Muscarinic cholinergic receptors
-ACh
-IP3, and increased intracellular [Ca++] - . . ANSWER ✓✓ PNS salivary stimulation:
-Receptors?
-NT?
-2nd messenger?
**Decreased parasympathetic (vagal) outflow to the heart and increased sympathetic outflow to the
heart and blood vessels:
,2|Page
1. Increased HR
2. Increased contractility and stroke volume
**Increased HR and SV together produce an increased CO, which increases arterial pressure.
3. Increased vasoconstriction of arterioles
4. Increased venoconstricition (veins) to increase venous return to the heart - . . ANSWER ✓✓
*Apneustic center* (lower pons): stimulates deep and prolonged inspiration.
*Pneumotaxic center* (upper pons): Inhibits inspiration - . . ANSWER ✓✓ What are the two Pontine
respiratory centers?
What are their functions?
*At rest*: sympathetic control is important (alpha-1 receptors = vasoconstriction; Beta-2 receptors=
vasodilation)
*During exercise*: Local metabolic control is most important (Lactate, K+, and adenosine INCREASE
blood flow to muscles) - . . ANSWER ✓✓ Most important mechanism of active hyperemia to the muscle
during rest? During exercise?
*Dorsal respiratory group*: responsible for normal inspiration and generates the basic rhythm for
breathing. (receives input from vagus and glossopharyngeal nerves)
*Ventral respiratory Group*: primarily responsible for expiration.
**Not active during normal breathing when expiration is passive; activated when expiration becomes an
active process. - . . ANSWER ✓✓ What are the two medullary respiratory centers?
What are their functions?
*Increase* blood flow
or
,3|Page
*decrease* cross sectional area
**site of slowest blood velocity= capillaries due to having the largest total cross-sectional area. - . .
ANSWER ✓✓ Increase the velocity of blood flow by:
__________ blood flow
or
___________ cross-sectional area
*Increasing* the viscosity of blood
*Increasing* the length of the vessel
*Decreasing* the radius of the vessel
**Decreased radius Has a HUGE effect on increasing resistance. - . . ANSWER ✓✓ Resistance to blood
flow can be increased by:
__________ the viscosity of blood
___________ the length of the vessel
___________ the radius of the vessel
(Poiseuilles equation)
*Isometric* contraction
*Isotonic* contraction - . . ANSWER ✓✓ Contractions that are measured when *length* is held
constant?
, 4|Page
Contractions that are measured when *load* is held constant?
*Medium-sized bronchi*
**Not the smallest bronchi because of their parallel arrangement - . . ANSWER ✓✓ Bronchi with the
largest resistance in the airway?
*Pulsatile* GnRH release from the hypothalamus
**FSH and LH are secreted in a pulsatile fashion
**GnRH up regulates its own receptor in the anterior pituitary - . . ANSWER ✓✓ Puberty in males and
females is initiated by?
0 and 10 mmHg
**If 02 does not equilibrate between alveolar gas and arterial blood, then PA02 will be greater than
Pa02 - . . ANSWER ✓✓ Normal A-a gradient is in what range?
1 M CaCl2 because the conc. of particles is higher. - . . ANSWER ✓✓ Which has a higher osmotic
pressure: 1 M CaCl2 or 1 M KCl?
1. *INCREASED fiber size*: increased diameter= decreased internal resistance= increased conduction
velocity
2. *myelination*: allows for saltitiory conduction at nodes of Ranvier. - . . ANSWER ✓✓ What two things
increase conduction velocity in nerves?
1. *Increased HR*: more action potentials occurring per unit time= more intracellular Ca++ stored in the
SR= more Ca++ released from the SR= stronger contraction
