Question 1

Which of the following best explains why steroid hormones typically have longer-lasting effects compared to peptide hormones?

Accepted Answer

Steroid hormones bind to cytosolic or nuclear receptors, altering gene expression and protein synthesis, resulting in prolonged effects.

Question 2

A patient presents with symptoms of hyperthyroidism, including weight loss, increased heart rate, and a goiter. Laboratory tests show elevated T3 and T4, but low TSH. Which condition is most likely?

Accepted Answer

Grave’s Disease

Question 3

Which equation is used to calculate the equilibrium potential for a single ion, such as potassium ($$K^+$$), across a membrane?

Accepted Answer

Nernst Equation: $$E_{ion} = \frac{RT}{zF} \ln \left( \frac{[ion]_{out}}{[ion]_{in}} \right)$$

Question 4

Which of the following is a primary function of aldosterone?

Accepted Answer

Promote sodium reabsorption in the kidneys, increasing blood volume and pressure

Question 5

A neuron receives multiple excitatory postsynaptic potentials (EPSPs) and inhibitory postsynaptic potentials (IPSPs) at the axon hillock. Which process determines whether an action potential will be generated?

Accepted Answer

Integration of both temporal and spatial summation of EPSPs and IPSPs

Question 6

Which of the following best describes the mechanism of insulin secretion from pancreatic beta cells in response to increased blood glucose?

Accepted Answer

Glucose enters the cell, increasing ATP, closing $$K^+$$ channels, causing depolarization, opening $$Ca^{2+}$$ channels, and triggering insulin release.

Question 7

Which of the following is a distinguishing feature of thyroid hormones (T3 and T4) compared to other amino acid-based hormones?

Accepted Answer

They are transported in the blood bound to carrier proteins and bind to nuclear receptors.

Question 8

A patient with Addison’s disease is likely to have which of the following laboratory findings?

Accepted Answer

Low cortisol, high ACTH

Question 9

Which glial cell is responsible for myelinating axons in the peripheral nervous system (PNS)?

Accepted Answer

Schwann cell

Question 10

Which neurotransmitter is released at the neuromuscular junction and acts on ionotropic receptors?

Accepted Answer

Acetylcholine acting on nicotinic receptors

Question 11

Which of the following best describes the effect of botulinum toxin on synaptic transmission?

Accepted Answer

It blocks acetylcholine release, causing flaccid paralysis.

Question 12

Which structure in the eye is primarily responsible for the majority of light refraction?

Accepted Answer

Cornea

Question 13

Which of the following best explains why patients with Type I Diabetes Mellitus have glucose in their urine?

Accepted Answer

Beta cells fail to produce insulin, leading to hyperglycemia and exceeding renal glucose reabsorption capacity.

Question 14

Which of the following is true regarding the propagation of action potentials in myelinated axons?

Accepted Answer

Action potentials jump from node to node (Nodes of Ranvier) via saltatory conduction.

Question 15

Which hormone is released from the posterior pituitary and is involved in water reabsorption in the kidneys?

Accepted Answer

Antidiuretic hormone (ADH)

Question 16

Which of the following best describes the effect of parathyroid hormone (PTH) on blood calcium levels?

Accepted Answer

PTH increases blood calcium by stimulating osteoclast activity and increasing renal reabsorption.

Question 17

Which of the following is a consequence of damage to the cochlear hair cells in the Organ of Corti?

Accepted Answer

Sensorineural deafness

Question 18

Which of the following best describes the difference between graded potentials and action potentials?

Accepted Answer

Graded potentials can summate and vary in amplitude, while action potentials are all-or-none and have a fixed amplitude.

Question 19

Which of the following is a primary function of the hypothalamic-pituitary portal system?

Accepted Answer

To deliver hypothalamic releasing and inhibiting hormones directly to the anterior pituitary.

Question 20

Which of the following best describes the effect of oxytocin during childbirth?

Accepted Answer

Oxytocin stimulates uterine contractions via positive feedback.

Physiology Exam 2: Endocrine and Nervous System Study Guide

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