The Nervous System and Sense Organs Flashcards

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1
Q

Coordination is the way in which [__] receive a stimulus and communicate with an [__]. The two systems involved include the [__] system and the [__] system.

A

receptors - effector - nervous - endocrine

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2
Q

❥ A [__] is any change in the internal or external organism’s environment that can cause a response or reaction in the organism.
❥ The specialized cell that detects a stimulus is called a [___].
❥ The body part that responds to a stimulus is called an [___].

A

❥ stimulus
❥ receptor
❥ effector

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3
Q

❥[___] neurons connect a [___] to the [__] so they convey sensory impulses to the brain and spinal cord.
❥ [__] neurons connect the [__] to an [__] so they transmit motor impulses from the brain or spinal cord to the muscle or gland.
❥ [__] neuron or interneuron carries impulses from the [__] neuron to the [__] neuron and are located in the CNS. Therefore, they conduct impulses between different parts of the CNS.

A

❥ Sensory - receptor - CNS
❥ Motor - CNS - effector
❥ Relay - sensory - motor

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4
Q

Describe saltatory conduction.
❥ [__ __] is a fatty insulating sheath (layer) that surrounds the axon.
❥ Myelin sheath is made by the [__] cells present at the axons.
❥ Mylein sheath is interrupted at the nodes of [__].
❥ The electrical impulse, traveling down a [__ __], cannot move through the axon in the insulated regions and, thus, skips over these insulated regions, jumping from one node to the next in a process called [__ __].
❥ The [__ __] is conducted very rapidly by saltatory conduction.

A
❥ Mylein sheath
❥ Schwann
❥ Ranvier
❥ myelinated axon - saltatory conduction
❥ nerve impulse
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5
Q

A [__] is the junction between two adjacent neurons, including the [__] cleft together with the ends of the presynaptic and the [__] neurons on either sides of the cleft.

A

synapse - synaptic - postsynaptic

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6
Q

In a [__ __], which is a very rapid response to a particular stimulus, the pathway taken by the nerve impulse from the receptor to the effector is called a [__ __].

A

reflex action - reflex arc

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7
Q

The components of the reflex arc in sequential order are the receptor, [__ __], relay neuron in CNS, [__ __], and the [__].

A

sensory neuron - motor neuron - effector

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8
Q

Where is the cell body of a motor neuron located in a hand withdrawal reflex
action?

A

The cell body of a motor neuron is located in the grey matter of the spinal cord.

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9
Q

Which neuron has its cell body entirely inside the central nervous system?

A

The relay neuron is entirely inside the central nervous system.

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10
Q

The cell body of the sensory neuron is located in the [__], which is a collection of cell bodies outside the [__].

A

ganglion - CNS

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11
Q

When light stimulates the rods and cones in the retina, a [__] nerve, called the optic nerve, carries nerve impulses generated by these receptors to the brain.

A

cranial -

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12
Q

❥ The choroid is [__] the retina.
❥ The choroid is [__] in humans, it absorbs [__] light scattered from the retina, thus preventing blurring of vision.
❥ It also contains many [__ __] to [__] the eye.

A

❥ behind
❥ black - excess
❥ blood vessels - nourish

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13
Q

The fovea is the part of the retina where cone cells are most [__ __]. The sharpest and most detailed color image is produced when light falls on the [__].

A

densely packed - fovea

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14
Q

The white, tough, opaque outer layer of the eye is called the [__]. The sclera is an [__] layer and thus it does not allow light into the eye.

A

sclera - opaque

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15
Q

The opaque, colored, circular part of the eye, which can be seen through the transparent cornea, is called the [__]. A gap, which looks like a black circle, at the center of the iris is called the [__]. It allows light to enter the eyes.

A

iris - pupil

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16
Q

Describe the muscles of the iris.
❥ The muscles of the iris are responsible for the changes in [__ __] observed in a pupil reflex. They control the amount of [__] entering the eye by [__] the diameter of the pupil.
❥ The iris consists of [__ __] sets of muscles that regulate the size of the [__]. The [__] muscles and the [__] muscles.
❥ The circular muscles [__] the pupil. The radial muscles [__] out from the edge of the pupil.

A

❥ pupil diameter - light - regulating
❥ 2 antagonistic - pupil - circular - radial
❥ encircle - radiate

17
Q

What does the suspensory ligaments do?

A

The suspensory ligaments hold the lens in place and attach it to the ciliary muscle

18
Q

The diameter of the pupil can be regulated by a cranial reflex action called the [__ __].

A

pupil reflex

19
Q

The pupil reflex protects the [__] from damage due to excess light and allows more light to reach the retina in dim light for better vision.

A

retina

20
Q
When walking into a brightly lit room:
❥ Radial muscles of the iris [\_\_].
❥ Circular muscles of the iris [\_\_].
❥ Pupil becomes [\_\_].
❥ [\_\_] light is allowed into the eye preventing damage of the [\_\_].
A

❥ relax
❥ contract
❥ smaller
❥ Less - retina

21
Q
When walking into a dim room or dark room:
❥ Radial muscles of the iris [\_\_].
❥ Circular muscles of the iris [\_\_].
❥ Pupil becomes [\_\_].
❥ [\_\_] light is allowed into the eye.
A

❥ contract
❥ relax
❥ larger
❥ More

22
Q

Accommodation is the ability to focus on objects at [__ __]. The ciliary muscle is responsible for the [__ __].

A

varying distances - accommodation reflex

23
Q

Explain how the eye accommodates for a distant object?
❥ To accommodate the eye for a distant object, the [__] muscles [__].
❥ The suspensory ligaments are pulled [__]
❥ which then pulls the lens so that it becomes [__], [__] and [__].
❥ The parallel rays of light from the distant object are bent [__] and focused on the [__] of the [__].

A

❥ ciliary - relax
❥ tight
❥ thin - longer - less convex
❥ less - fovea - retina

24
Q

Describe how the eye accommodates for a near object.
❥ To accommodate the eye for a near object, the [__] muscles [__].
❥ This causes the suspensory ligaments to become [__]
❥ releasing tension on the lens, which then becomes [__], [__] and [__ __].
❥ The light bends [__] and the divergent rays of light from the near object are bent strongly to focus them on the [__] of the [__].

A

❥ ciliary - contract
❥ slack
❥ thicker - shorter - more convex
❥ more - fovea - retina