Homeostasis and Reflex Arcs Educake

Question 1

Aside from the spinal cord, give an example of a coordination centre in an automatic control system.

Answer 1

The brain
the brain is a coordination centre in an automatic control system. Automatic reactions are quick and unlearned.

Question 2

a light receptor cell

Question 3

In a reflex action, muscles respond by doing what?

Answer 3

contracting
When muscles receive impulses from nerves, they contract.

Question 4

Automatic control systems always include three things

Answer 4

receptors, coordination centres and effectors.

Question 5

What is the name of the system that enables humans to react to their environment?

Answer 5

The nervous system

The nervous system allows humans to react to their environment and to coordinate their behaviour.

Question 6

Blood sugar levels of the body need to be maintained, along with what other internal condition?

Answer 6

The human body maintains its internal environment within narrow limits.
Blood sugar levels,
temperature,
water content
and salt concentration
are all monitored.

Question 7

What part of the CNS is not usually involved in an unconditioned reflex?

Answer 7

An unconditioned reflex is a reflex that we are born with. It does not have to be learnt and does not involve the brain.

Question 8

What is the word for an organ or tissue that brings about the response in a reflex action?

Answer 8

An effector organ is an organ that brings about a response (effect) in a reflex action.

Question 9

What is the name of the junction between two neurones?

Answer 9

The junction between two neurones is called a synapse. It is a tiny gap between two neurones.

Question 10

What is the common reflex action in the eye usually called?

Answer 10

The blinking reflex is an automatic response brought about by an external stimulus.

Question 11

Effectors can be either muscles or what?

Answer 11

glands

Glands, along with muscles, are effectors which bring about a response in a reflex action.

Question 12

One word to describe a reflex action is automatic. What is the other word that means you cannot control it?

Answer 12

The body has no control over reflex actions. They happen automatically and can also be described as involuntary.

Question 13

What type of cell in the nervous system detects a change in the environment?

Answer 13

Receptor cells are an important part of the nervous system. They are found in various parts of the body and detect changes in the environment.

Question 14

Water content, ion content and blood sugar levels of the body need to be maintained, along with what other internal condition?

Answer 14

Body temperature must be maintained within narrow limits to ensure that chemical reactions can take place optimally.

Question 15

What is the name of the cells found in nerves that carry information?

Answer 15

Neurones

Neurones are specialised cells adapted to carry electrical impulses from one place to another.

Question 16

How does the speed of reflex actions compare to normal responses? Are they faster or slower than normal responses?

Answer 16

A reflex action is a rapid, automatic response to a stimulus, hence it is faster than normal responses.

Question 17

What stimulus is a receptor in the eye sensitive to?

Answer 17

light

Receptors in the eye are sensitive to light.

Question 18

Which system has longer lasting effects: the nervous system or hormonal system?

Answer 18

Hormonal responses can last a long time, whereas nervous system responses are short lived.

Question 19

Glands secrete __________ in reflex actions. What is the missing word?

Answer 19

hormones

Glands are found in many parts of the body. They secrete chemicals in response to a stimulus.

Question 20

The brain coordinates the __________ to a stimulus. What word completes this sentence?

Answer 20

reaction

The function of the brain is to process information and coordinate a response.

Question 21

In a reflex action, impulses from a receptor cell travel along what kind of neurone first?

Answer 21

A sensory neurone
is the first neurone an impulse travels along in a reflex action. The sensory neurone transmits an impulse from a receptor to the central nervous system.

Question 22

What is the word for a change in the environment that a receptor cell responds to?

Answer 22

A stimulus

A stimulus is a change in the environment that brings about a specific response.

Question 23

What stimuli are receptors in the nose and tongue sensitive to?

Answer 23

chemicals

The nose has receptors sensitive to chemicals in the air and the tongue has receptors sensitive to chemicals in the food we eat.

Question 24

Which system is able to respond to change faster: the nervous system or hormonal system?

Answer 24

The nervous system responds to change very rapidly, whereas the hormonal system responds slowly.

Question 25

What type of actions involving the nervous system are automatic and very fast?

Answer 25

A reflex action is a quick, unlearned and automatic response to a stimulus.