Nervous system

Question 1

What ear structure is used in perception of pitch ?

Answer 1

***Basilar membrane **

Sound waves are transmitted to the basilar membrane, causing it to vibrate. The location along the basilar membrane that experiences maximal vibration determines a person’s perception of pitch

Question 2

What body structures use hair cells to detect motion

Answer 2

**Organ of Corti and semicircular canals **

(Movement of the fluid around the hair cells detects sound in the organ of Corti and a change in body orientation in the semicircular canals)

Question 3

What processes always result in a negative membrane potential ?

Answer 3

Repolarization and hyper polarization

Question 4

What occurs in Repolarization ?

Answer 4

Repolarization is defined as a return to resting membrane potential (RMP).
Since the RMP is negative (–70 mV)

Question 5

differentiate between rods and cones?

Answer 5

Cones transduce color for the brain, while rods respond to black and white images.

Question 6

What are the major effects of sympathetic nervous system ?

Answer 6

effects of the sympathetic system:
- release Acetylcholine onto the adrenal medulla ( this triggers the release of epinephrine into the blood to enhance and prolong the overall effects of the system)
- Among those effects are increased heart rate and force of cardiac contraction, DILATION of bronchial tubes (to increase the volume of air that can enter the lungs,) and increased blood flow to skeletal muscles to ensure adequate delivery of glucose and oxygen during stress situations.
sympathetic ns also increases pupil DILATION, this increases distance vision

Question 7

What is the role of basilar membrane ?

Answer 7

. The basilar membrane supports the hair cells of the ear (the sound receptors), and vibrates in sound waves.

Question 8

What happens if cochlea is damaged?

Answer 8

cochlea is a large, curled structure in the inner ear, Damage to cochlear will hinder the detection of particular frequencies.

Question 9

Which senses rely on chemoreceptors ?

Answer 9

Taste and Olfaction

Question 10

Which sense relies on mechanoreceptors ?

Answer 10

Touch primarily on mechanoreceptors ( and somewhat on nociceptors (pain) and thermoreceptors (temperature)) ,

Question 11

What does NOT rely on neural stimulation (use of action potentials) ?

Answer 11

Heart contraction does NOT relay on neural stimulation

Question 12

What can occur due to poisoning and voltage-gated sodium channels are blocked

Answer 12

Blocking the action of voltage-gated sodium channels in neurons would prevent the occurrence of action potentials, leading to skeletal muscle paralysis. Because the diaphragm is made of skeletal muscle, it too would become paralyzed, leading to respiratory failure and death.

Question 13

What is difference threshold ?

Answer 13

Difference threshold: is the minimum difference needed between two stimuli to be able to detect that there is in fact a difference at least 50% of the time.

ex: The “weighing” of the cantaloupes best describes this, as perceiving a difference in their size would require them to be proportionally distinct in their mass.

Question 14

On what part of the retina does the image focus on when you stare directly at something?

Answer 14

Fovea centralis (aka focal point) that is responsible visual acuity (test how sharp you can see something at a distance) The lens is not part of the retina, but rather it is in front of the retina. Its role is to focus incoming light beams onto the retina. The pupil is also not part of the retina. Its role is to control the amount of light that enters the eye. While the optic disk is part of the retina, it has no photoreceptors. For this reason, it is also called the blind spot.

Question 15

What is the role of lens ?

Answer 15

The lens is in front of the retina. Its role is to focus incoming light beams onto the retina.

Question 16

What is the role of pupil ?

Answer 16

Pupil’s role is to control the amount of light that enters the eye.

Question 17

What is the role of optic disk ?

Answer 17

optic disk is located in back of eye (where retina and optic nerve connect) . it has photoreceptors and is also called BLIND SPOT

Question 18

How do you differentiate between axon hillock, and soma ?

Answer 18

The axon hillock: area linking the soma to the axon, possesses an increased voltage-gated sodium channel density, allowing it to fire action potentials.
In the soma, the decreased density allows for local Depolarization which degrades exponentially over the distance of the soma.

Question 19

What is the role of voltage gated potassium channels ? what will occur if these channels are blocked ?

Answer 19

voltage-gated potassium channels are critical for REPOLARIZING the cell;
if these are blocked, the cell will remain in a Depolarized state for much, much longer than normal. This would prevent the firing of subsequent action potentials and time to return to resting poetical will be long

Question 20

What is the role of post vs preganglionic neurons ?

Answer 20

Postganglionic neurons directly stimulate target tissues.
preganglionic neurons stimulate postganglionic neurons.

Question 21

What is role of postganglionic neurons ?

Answer 21

Sympathetic postganglionic neurons could directly stimulate the relaxation of bronchial smooth muscle. Relaxation of bronchial smooth muscle is an involuntary process that is triggered by activation of the sympathetic nervous system.

Question 22

Does the sympathetic nervous system cause the heart to contract ?

Answer 22

NO, The heart is AUTORHYTHMIC and can generate its own contraction without input from the nervous system.

However, activation of the sympathetic division can make the heart contract more frequently (i.e., increase the heart rate).

Question 23

How does sympathetic nervous system activation affect smooth muscles that serve skeletal muscle ?

Answer 23

Sympathetic NS RELAXES smooth muscle in blood vessels that serve skeletal muscle causing DILATION of blood vessels and Increased blood flow

Question 24

How does sympathetic nervous system affect smooth muscle that affect skin and digestive organs ?

Answer 24

The sympathetic nervous system CONSTRICTS blood vessels that serve skin and digestive organs (contract smooth muscle)

Question 25

Which cell produces myelin in Peripheral Nervous system ?

Answer 25

Schwann cells

Question 26

Which cells produces myelin in Central nervous system ?

Answer 26

Oligodendrocytes

Question 27

How do Schwann cells play a role in axonal transmission ?

Answer 27

Schwann cells insulate the axons of neurons, causing membrane depolarization to jump from node to node.

Question 28

What is the pathway of light from anterior surface of eye to optic nerve ?

Answer 28

The correct pathway of light : cornea—>anterior chamber–> lens—> retina.

Question 29

How do photoreceptors of the eye respond to stimulation of light ?

Answer 29

When the photoreceptors of the eye are stimulated by light:
light closes Na+ channels, the cells become hyperpolarized and the optic nerve is stimulated.

Question 30

Where are the cell bodies of somatic sensory neuron located ?

Answer 30

DORSAL ROOT GANGLION

Question 31

What processes does the hypothalamus regulate ?

Answer 31

food intake, blood pressure, and neuroendocrine control, as well as temperature regulation.

Question 32

What occurs to image in myopia ?

Answer 32

In myopia, the image formed by lens is in FRONT of the retina, generally due to the shape of the eye being too long.

Question 33

What is absolute threshold ?

Answer 33

Absolute threshold : is the minimum amount of stimulation needed to achieve activation of sensory receptors 50% of the time;