Coordination

Question 1

What are the extensions at the end of the neuron cell body called?

Answer 1

Dendrons. Which in turn form finer extensions called dendrites.

Question 2

Whats the axon?

Answer 2

A long cable that snakes away from the cell. This is where electrical impulses from the neuron travel away to be received by other neurons.

Question 3

Whats the neuromuscular junction?

Answer 3

Where nerves and muscle fibers meet.

Question 4

Whats the myelin sheath?

Answer 4

Insulates the axon and prevents short circuits with other axons.

Question 5

Whats a sensory neuron?

Answer 5

Similar structure to motor neuron but the cell body is located on the side branch of the fiber.

Question 6

Whats the sclera?

Answer 6

The visible white part of the eye

Question 7

Whats the cornea?

Answer 7

The transparent part of the eye that covers the iris and the pupil and allows light to enter the inside.

Question 8

Whats the iris?

Answer 8

The colored tissue at the front of the eye. Helps control the size of the pupil.

Question 9

Whats the pupil?

Answer 9

The middle black part of the eye. It controls the amount of light entering the eye.

Question 10

Whats the choroid?

Answer 10

A thin layer of tissue that is part of the middle layer of the wall of the eye. Its filled with blood vessels that bring oxygen and nutrients to the eye.

Question 11

Whats the retina?

Answer 11

The back layer of the eye. Its the light sensitive layer that converts light energy to electrical energy of nerve impulses.

Question 12

What are the rods and cones in the eye?

Answer 12

Inside the retina. They react to light producing impulses in sensory neurons.

Question 13

Whats the optic nerve?

Answer 13

The nerve that carries messages from the retina to the brain.

Question 14

Whats the fovea?

Answer 14

An area at the center of the retina where the cones are especially concentrated.

Question 15

How is an image formed?

Answer 15

The retina receives the image that the cornea focuses through the eye’s internal lens and transforms this image into electrical impulses that are carried by the optic nerve to the brain.

Question 15

Whats accommodation?

Answer 15

The changes that take place in the eye which allow us to see objects at different distances are called accommodation.

Question 16

How do we see at a shorter distance?

Answer 16

ciliary muscles contract + zoonule fibers loosen creating a rounder lens and a higher refractive power

Question 17

How do we see at a longer distance?

Answer 17

ciliary muscles relax + zoonule fibers increase in tension creating a flattening of the lens

Question 18

How does a reflex work?

Answer 18

Pain detectors detect stimulus —> Generates impulses in sensory neurons —> Impulses enter –> dorsal root —> Enter CNS —> Inside spinal cord, sensory neuron use synapses to connect with short relay neurons —> which in turn connect with motor neurons —> motor neurons emerge from the spinal cord through the ventral root —> send impulses back to the muscles of the area —> These muscles contract —> appropriate reaction.

Question 18

What are synapses?

Answer 18

The point of contact between neurons where information is passed from one neuron to another.
Its actually a gap between 2 nerve cells.

Question 19

How do synapses work?

Answer 19

The gap between synapses is crossed by chemicals —> When impulses arrive at a synapse, the ends of the axon branches secrete a chemical called neurotransmitter —> This chemical diffuses across the gap and attaches to the membrane of the second neuron —> After the neurotransmitter has “passed the message”, its broken down by the enzyme.