Chapter 15, Coordination

Question 1

What is an axon?

Answer 1

A long, slender projection of a nerve cell, or neuron, that typically conducts electrical impulses known as action potentials away from the nerve cell body.

Question 2

What is the function of an axon?

Answer 2

To transmit information to different neurons, muscles, and glands.

Question 3

How do neurons work?

Answer 3

1) Electrical impulse is sent from a nerve receptor and travels along the axon
2) At nerve ending there is a gap called the synapse. It works as the electrical impulse and triggers the release of neurotransmitters.

Question 4

What is a reflex arc?

Answer 4

• Pathway which imp. are transmitted from receptor to an effector without involving the conscious parts of brain.
• Imp. travel from sensory to relay ( not always) to motor.
• In spinal cord, imp. are passed onto other n. that goes up to brain. At same time passing through m.n.
• Therefore effector acts before brain could process, hence its a reflex action.

Question 5

What are the three types of neurons?

Answer 5

Sensory.
Relay.
Motor.

Question 6

What is a stimulus?

Answer 6

Change in an organisms surroundings.

Question 7

What are receptors?

Answer 7

Something which detects changes. Converts stimulus energy into electrical impulses.

Question 8

What is an effector?

Answer 8

Muscle or gland that brings a response to the stimulus.

Question 9

What are electrical impulses passed through?

Answer 9

The nervous system and back to the effector.

Question 10

Exteroreceptors:

Answer 10

Detect stimuli coming form the outside of the body.

Question 11

Interceptors:

Answer 11

Detect stimuli. All stimuli represents forms of energy.

Question 12

Sensation:

Answer 12

Involves converting this energy into a change in the membrane potential of sensory receptors.

Question 13

Sensory receptors perform four functions:

Answer 13

Sensory transduction
Amplification
Transmission
integration

Question 14

Types of sensory receptors (five categories):

Answer 14

• Mechanoreceptors
• Chemoreceptors
• Electromagnetic receptors
• Thermoreceptors
• Pain receptors

Question 15

Mechanoreceptors:

Answer 15

Sense physical deformation caused by a stimuli such as pressure, stretch, motion, and sound.

Question 16

Chemoreceptors:

Answer 16

1. Include general receptors that transmits information about the total solute concentration of a solution.
2. Specific receptors that respond to individual kinds of molecules.

Question 17

Electromagnetic receptors:

Answer 17

Detect various forms of electromagnetic energy such as light, electricity, and magnetism.

Question 18

Thermoreceptors:

Answer 18

Respond to heat or cold. Help regulate body temperature by signaling both surface and body core temperature.

Question 19

Pain receptors:

Answer 19

Naked dendrites in the epidermis. Respond to excess heat, pressure, or specific classes of chemical released from damaged or inflamed tissues.

Question 20

The autonomic system:

Answer 20

Sympathetic and the parasympathetic systems.

Question 21

The sympathetic system:

Answer 21

Puts the body in the alarm readiness and increases metabolism, correlates with the “fight-or-flight” response while the parasympathetic systems generally stimulates the body to do more relaxing activities, such as digestion, promotes a return to self-maintenance functions.

Question 22

Sensory neurone:

Answer 22

Transmit impulses from receptors to CNS.

Question 23

Ganglion:

Answer 23

• Cell body near source of stimulus or swelling of spinal cord.

Question 24

Intermediate Neurone:

Answer 24

• Transmit impulse from sensorn to motor neurone

- Found entirely in CNS

Question 25

Motor Neurone:

Answer 25

• Transmit impulses from CNS to effector.
• Cell body lines within CNS and contains the nucleus.
• Dark specs in c.p. are rough ER regions.

Question 26

Myelin:

Answer 26

• Made by Schwann cells.

- Axons of m.n and s.n surrounded by thick dark rings of myelin.

Question 27

Schwann Cells:

Answer 27

• Specialised Cells.
• Made of lipid and some proteins.
• Wrap themselves around axons enclosing it in many layers. Uncovered regions between these cells = Nodes of Ranvier.