Question 1

Which of the following cell types in the retina have axon potentials?

Accepted Answer

A) Ganglion cells 
B) Amacrine cells 
C) Bipolar cells 
D) Horizontal cells 
A) Ganglion cells 
B) Amacrine cells 
C) Bipolar cells 
D) Horizontal cells A

Question 2

Under low or reduced light conditions, which of the following is responsible for the inward-directed sodium current in the outer segments of the photoreceptors?

Accepted Answer

A) Metarhodopsin II 
B) cGMP 
C) cis-retinal 
D) cAMP 
A) Metarhodopsin II 
B) cGMP 
C) cis-retinal 
D) cAMP B

Question 3

Which of the following best describes the central fovea of the eye?

Accepted Answer

A) Cones only, highest visual acuity 
B) Cones only, lowest visual acuity 
C) Rods only, highest visual acuity 
D) Rods only, lowest visual acuity 
A) Cones only, highest visual acuity 
B) Cones only, lowest visual acuity 
C) Rods only, highest visual acuity 
D) Rods only, lowest visual acuity A

Question 4

Which of the following substances is responsible for activation of transducin during photoreception?

Accepted Answer

A) cGMP 
B) All-trans-retinal 
C) Rhodopsin 
D) Metarhodopsin II 
A) cGMP 
B) All-trans-retinal 
C) Rhodopsin 
D) Metarhodopsin II

Question 5

During photoreception all of the following increase except:

Accepted Answer

A) cGMP phosphodiesterase 
B) Transducin 
C) Metarhodopsin II 
D) Sodium influx into the outer segment of the rod 
A) cGMP phosphodiesterase 
B) Transducin 
C) Metarhodopsin II 
D) Sodium influx into the outer segment of the rod

Question 6

Visual acuity is highest at the fovea centralis partly because each cone cell synapses with multiple ganglion cells in the fovea centralis.

Accepted Answer

A) Both the statement and the reason are correct and related. 
B) Both the statement and the reason are correct but not related. 
C) The statement is correct but the reason is not. 
D) The statement is not correct, but the reason is correct. 
E) Neither the statement nor the reason is correct. 
A) Both the statement and the reason are correct and related. 
B) Both the statement and the reason are correct but not related. 
C) The statement is correct but the reason is not. 
D) The statement is not correct, but the reason is correct. 
E) Neither the statement nor the reason is correct.

Question 7

Males have a higher incidence of color blindness compared with females because of a genetic disorder passed along by which of the following?

Accepted Answer

A) X and Y chromosome 
B) X chromosome only 
C) X or Y chromosome 
D) Y chromosome only 
A) X and Y chromosome 
B) X chromosome only 
C) X or Y chromosome 
D) Y chromosome only

Question 8

In the retina, the activation of adjacent rods and cones is prevented by the phenomenon of lateral inhibition. Which cell type is thought to be responsible for this process?

Accepted Answer

A) Bipolar cells 
B) Horizontal cells 
C) Ganglion cells 
D) Amacrine cells 
A) Bipolar cells 
B) Horizontal cells 
C) Ganglion cells 
D) Amacrine cells

Question 9

Rhodopsin decomposes on exposure to light, causing which of the following in rods of the retina?

Accepted Answer

A) Depolarization, decreased sodium conductance 
B) Depolarization, increased sodium conductance 
C) Hyperpolarization, decreased sodium conductance 
D) Hyperpolarization, increased sodium conductance 
A) Depolarization, decreased sodium conductance 
B) Depolarization, increased sodium conductance 
C) Hyperpolarization, decreased sodium conductance 
D) Hyperpolarization, increased sodium conductance

Question 10

Which of the following best describes cones of the retina?

Accepted Answer

A) Black and white 
B) Blue, green, violet 
C) Blue, yellow, orange 
D) Red, blue, green 
E) Red, blue, yellow 
A) Black and white 
B) Blue, green, violet 
C) Blue, yellow, orange 
D) Red, blue, green 
E) Red, blue, yellow

Question 11

Which of the following factors has a direct action to control sodium channel gating in rods of the retina?

Accepted Answer

A) Acetylcholine 
B) Cyclic adenosine monophosphate 
C) Cyclic guanosine monophosphate 
D) Norepinephrine 
E) Transducin 
A) Acetylcholine 
B) Cyclic adenosine monophosphate 
C) Cyclic guanosine monophosphate 
D) Norepinephrine 
E) Transducin

Question 12

Which of the following vitamins is essential for preventing night blindness?

Accepted Answer

A) A 
B) B 
C) C 
D) D 
E) E 
A) A 
B) B 
C) C 
D) D 
E) E

Question 13

Which area of the retina is responsible for the greatest visual acuity in humans?

Accepted Answer

A) Fovea 
B) Optic disc 
C) Pigment layer 
D) Central fovea 
A) Fovea 
B) Optic disc 
C) Pigment layer 
D) Central fovea

Question 14

A 45-year-old woman with a vitamin A deficiency is most likely to have increased levels of which of the following substances in rods of the retina?

Accepted Answer

A) Activated transducin 
B) Cyclic guanosine monophosphate 
C) Rhodopsin 
D) Scotopsin 
A) Activated transducin 
B) Cyclic guanosine monophosphate 
C) Rhodopsin 
D) Scotopsin

Exam 51: The Eye: II Receptor and Neural Function of the Retina

Which of the following cell types in the retina have axon potentials?

Under low or reduced light conditions, which of the following is responsible for the inward-directed sodium current in the outer segments of the photoreceptors?

Which of the following best describes the central fovea of the eye?

Which of the following substances is responsible for activation of transducin during photoreception?

During photoreception all of the following increase except:

Visual acuity is highest at the fovea centralis partly because each cone cell synapses with multiple ganglion cells in the fovea centralis.

Males have a higher incidence of color blindness compared with females because of a genetic disorder passed along by which of the following?

In the retina, the activation of adjacent rods and cones is prevented by the phenomenon of lateral inhibition. Which cell type is thought to be responsible for this process?

Rhodopsin decomposes on exposure to light, causing which of the following in rods of the retina?

Which of the following best describes cones of the retina?

Which of the following factors has a direct action to control sodium channel gating in rods of the retina?

Which of the following vitamins is essential for preventing night blindness?

Which area of the retina is responsible for the greatest visual acuity in humans?

A 45-year-old woman with a vitamin A deficiency is most likely to have increased levels of which of the following substances in rods of the retina?

Functional Organization of the Human Body and Control of the Internal Environment

The Cell and Its Functions

Genetic Control of Protein Synthesis, Cell Function, and Cell Reproduction

Transport of Substances Through Cell Membranes

Membrane Potentials and Action Potentials

Contraction of Skeletal Muscle

Excitation of Skeletal Muscle: Neuromuscular Transmission and Excitation-Contraction Coupling

Excitation and Contraction of Smooth Muscle

Cardiac Muscle; the Heart As a Pump and Function of the Heart Valves

Rhythmical Excitation of the Heart

The Normal Electrocardiogram

Electrocardiographic Interpretation of Cardiac Muscle and Coronary Blood Flow Abnormalities: Vectorial Analysis

Cardiac Arrhythmias and Their Electrocardiographic Interpretation

Overview of the Circulation; Biophysics of Pressure, Flow, and Resistance

Vascular Distensibility and Functions of the Arterial and Venous Systems

The Microcirculation and Lymphatic System: Capillary Fluid Exchange, Interstitial Fluid, and Lymph Flow

Local and Humoral Control of Tissue Blood Flow

Nervous Regulation of the Circulation and Rapid Control of Arterial Pressure

Role of the Kidneys in Long-Term Control of Arterial Pressure and in Hypertension: the Integrated System for Arterial Pressure Regulation

Cardiac Output, Venous Return, and Their Regulation

Muscle Blood Flow and Cardiac Output During Exercise; the Coronary Circulation and Ischemic Heart Disease

Cardiac Failure

Heart Valves and Heart Sounds; Valvular and Congenital Heart Defects

Circulatory Shock and Its Treatment

The Body Fluid Compartments: Extracellular and Intracellular Fluids; Edema

Red Blood Cells, Anemia, and Polycythemia

Resistance of the Body to Infection: I Leukocytes, Granulocytes, the Monocyte-Macrophage System, and Inflammation

Resistance of the Body to Infection: Ii Immunity and Allergy

Blood Types; Transfusion; Tissue and Organ Transplantation

Hemostasis and Blood Coagulation

Pulmonary Ventilation

Pulmonary Circulation, Pulmonary Edema, Pleural Fluid

Physical Principles of Gas Exchange; Diffusion of Oxygen and Carbon Dioxide Through the Respiratory Membrane

Transport of Oxygen and Carbon Dioxide in Blood and Tissue Fluids

Regulation of Respiration

Respiratory Insufficiencypathophysiology, Diagnosis, Oxygen Therapy

Aviation, High Altitude, and Space Physiology

Physiology of Deep-Sea Diving and Other Hyperbaric Conditions

Organization of the Nervous System, Basic Functions of Synapses, and Neurotransmitters

Sensory Receptors, Neuronal Circuits for Processing Information

Somatic Sensations: I General Organization, the Tactile and Position Senses

Somatic Sensations: II Pain, Headache, and Thermal Sensations

The Eye: I Optics of Vision

The Eye: III Central Neurophysiology of Vision

The Sense of Hearing

The Chemical Sensestaste and Smell

Motor Functions of the Spinal Cord; the Cord Reflexes

Cortical and Brain Stem Control of Motor Function

Contributions of the Cerebellum and Basal Ganglia to Overall Motor Control

Cerebral Cortex, Intellectual Functions of the Brain, Learning, and Memory

Behavioral and Motivational Mechanisms of the Brainthe Limbic System and the Hypothalamus

States of Brain Activitysleep, Brain Waves, Epilepsy, Psychoses, and Dementia

The Autonomic Nervous System and the Adrenal Medulla

Cerebral Blood Flow, Cerebrospinal Fluid, and Brain Metabolism

General Principles of Gastrointestinal Functionmotility, Nervous Control, and Blood Circulation

Propulsion and Mixing of Food in the Alimentary Tract

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