Coordination And Control

Question 1

What does coordinated mean?

Answer 1

The body is able to make things happen in different parts of the body at the right time

Question 2

Humans & other animals have 2 organ systems which coordinate…

Answer 2

-the nervous system
-the endocrine (hormone) system

Question 3

What three elements are needed for a coordinated response in an organism?

Answer 3

-stimulus
-receptor
-effector

Question 4

What is phototropism?

Answer 4

the growth of a plant in response to the direction of light, where the plant grows towards the light source

Question 5

Define “stimulus” in the context of a coordinated response.

Answer 5

-Change in the animal’s surroundings
e.g. a ball is thrown towards you

Question 6

Define “receptor” in the context of a coordinated response.

Answer 6

-Is the organ which detects the change
e.g. your eye

Question 7

Define “effector” in the context of a coordinated response.

Answer 7

-Muscles are the effectors & they contract as you catch the ball

Question 8

How is the link between stimulus and response made?

Answer 8

-by the nervous or endocrine system.

Question 9

What do receptors do when they detect a stimulus?

Answer 9

-Receptors detect the stimulus & convert its energy into nerve impulses.

Question 10

Give an example of a sense organ acting as a receptor.

Answer 10

-The eye acts as a receptor by converting light energy into nerve impulses.

Question 11

Eye: Converts ______ into nerve impulses.

Answer 11

Eye: Converts light into nerve impulses.

Question 12

Tongue: Converts ______ into nerve impulses

Answer 12

Tongue: Converts chemical energy into nerve impulses

Question 12

Ear: Converts ______ into nerve impulses.

Answer 12

Ear: Converts sound into nerve impulses.

Question 13

Nose: Converts ______ into nerve impulses

Answer 13

Nose: Converts chemical energy into nerve impulses

Question 14

Skin (touch receptors): Converts ______ into nerve impulses

Answer 14

Skin (touch receptors): Converts pressure into nerve impulses

Question 15

Skin (temperature receptors): Converts ______ into nerve impulses

Answer 15

Skin (temperature receptors): Converts heat into nerve impulses

Question 16

Central Nervous System

Answer 16

-consists of the brain & spinal cord
-the CNS coordinates all of the nervous such as moving or reflexes

Question 17

Peripheral Nervous System

Answer 17

-The peripheral nervous system contains all of the other nerves
-Which send impulses to all the effectors

Question 18

What connects sense organs & effectors?

Answer 18

Nerve cells (neurones) connect sense organs & effectors.

Question 19

What are the three types of neurones?

Answer 19

-Sensory neurones
-Relay neurones
-Motor neurones

Question 20

What is the function of sensory neurones?

Answer 20

-Carry impulses from receptors to the CNS (brain & spinal cord).

Question 21

What is the role of relay neurones?

Answer 21

-Found in the CNS (brain & spinal cord).
-Transmit impulses from sensory neurones to motor neurones.

Question 22

Nucleus

Answer 22

-Contains all the genetic information of the cell

Question 23

Dendrite

Answer 23

-Tree like projections which connect to different neurones.
-One neurone can connect to many other neurones

Question 24

Cell body

Answer 24

-The main section of the cell.
-Contains the nucleus

Question 25

Axon

Answer 25

-The long section - electrical impulses travel long distances through the axon.

Question 26

Myelin Sheath

Answer 26

-Insulates the axon
-Speeds up the transmission of the impulse.

Question 27

What are reflexes?

Answer 27

-Automated actions
-Do not involve the brain
-Very fast responses
-Involve three types of neurones: sensory, relay, and motor

Question 28

What is a reflex arc?

Answer 28

-The pathway of nerve impulses from receptor to effector
-Involves the detection of a stimulus and a response
-e.g. moving a hand away from heat

Question 29

What happens when heat is detected?

Answer 29

-The receptors detect the change in temperature
-An impulse is sent along the sensory neurone
-The person quickly moves their hand away

Question 30

-Describe the role of the sensory neurone in a reflex arc.

Answer 30

-Carries the impulse from the receptor to the spinal cord

Question 31

What is the function of the relay neurone?

Answer 31

-Passes the impulse from the sensory neurone to the motor neurone
-Located in the spinal cord
-Transmits signals across synapses

Question 32

What is a synapse?

Answer 32

-The gap between two neurones
-Where the impulse is transmitted from one neurone to another

Question 33

What does the motor neurone do in a reflex arc?

Answer 33

-Carries the impulse to the effector
-Causes the effector (e.g., arm muscle) to contract
-Moves the arm away from the stimulus (e.g., fire)
-Shown in yellow in the diagram

Question 34

What is the overall sequence of a reflex action?

Answer 34

-Stimulus detected by receptors
-Impulse travels along sensory neurone to spinal cord
-Relay neurone transmits impulse to motor neurone
-Motor neurone activates effector to produce a response

Question 35

What is a synapse in the context of neurons?

Answer 35

• A synapse is a very small gap between two neurons.
• Neurons do not make direct contact at the synapse.
• Signals need to cross the synapse to continue their journey to or from the CNS (central nervous system).

Question 36

Describe the process of neurotransmission.

Answer 36

1. An electrical impulse travels along an axon.
   2.This triggers the nerve-ending of a neuron to release chemical
   messengers called neurotransmitters.
   3..These chemicals diffuse across the synapse (the gap) and bind with receptor
   molecules on the membrane of the next neuron.
2. The receptor molecules on the second neuron bind only to the specific
   chemicals released from the first neuron. This stimulates the second neuron
   to transmit the electrical impulse.

Question 37

What does the eye do as a sensory organ?

Answer 37

-Detects light
-Sends an impulse to the brain
-Brain converts the impulse into an image, this is what you see

Question 38

What happens to the eye in dim light?

Answer 38

-Radial muscles contract
-Circular muscles relax
-Iris becomes narrower
-Pupil dilates

Question 39

What happens to the eye in bright light?

Answer 39

-Circular muscles contract
-Radial muscles relax
-Iris becomes wider
-Pupil constricts

Question 40

What is the reflex arc for adjusting to light intensity?

Answer 40

-Retina detects light intensity
-Effectors are the iris muscles
-Adjusts pupil size in response to light

Question 41

What is accommodation in the eye?

Answer 41

-Adjustments made to see objects at different distances
-Involves changes in lens shape
-Enables clear vision for near and far objects

Question 42

How does the eye focus on a distant object?

Answer 42

• Light rays entering the eye are almost parallel when they reach the cornea.
  -The lens does not need to refract the light much to ensure it focuses onto the retina
• Ciliary muscles relax.
• Suspensory ligaments are pulled tight.
• Lens becomes thin and less convex.
• Less refraction of light is needed to focus onto the retina.

Question 43

How does the eye focus on a close-up object?

Answer 43

• Light rays entering the eye are diverging (spreading out).
  -The lens needs to refract the light to ensure it focuses onto the retina
• Ciliary muscles contract.
• Suspensory ligaments become slack.
• Lens is not stretched, becoming thicker and more convex.
• More refraction of light is needed to focus onto the retina