B5

Question 1

Define homeostasis

Answer 1

the maintenance of a stable internal environment

Question 2

Why does homeostasis need to maintain optimal conditions?

Answer 2

• so enzymes + cells don’t denature

- and for enzyme + cell to functions

Question 3

List three conditions that the body needs to maintain

Answer 3

• blood glucose concentration (bgc)
• temperature
• water

Question 4

What do the two automatic response systems involve?

Answer 4

• nervous response

- chemical response

Question 5

What does receptor do?

Answer 5

detects a stimuli

Question 6

What is a stimuli?

Answer 6

an environmental change

Question 7

List the receptor cells and state what stimulus they detect

Answer 7

• skin detects : touch, pressure, pain & temperature
• nose detects : chemicals in the air
• tongue detects : chemicals in food
• ears detects : change in sound
• eyes detects : changes in light and color

Question 8

What does a coordination center do?

Answer 8

receives and process the stimuli from a receptor

Question 9

Name the 3 coordination centers in the body and describe what each of them coordinates

Answer 9

• brain = coordinates information from the receptor cells and send signals to the muscles and glands
• spinal cord = coordinates messages from the brain ,receptor cells and coordinates reflexes
• pancreas = coordinates the glucose levels in the blood

Question 10

What is an effector and an example?

Answer 10

carries out responses to stimuli - either a muscle or gland

- example: muscles contracting to lift a leg

Question 11

Define the nervous system

Answer 11

it enables humans to react to their surrounding and to coordinates their behavior

Question 12

Describes what happens at the nervous system

Answer 12

• a stimulus (environmental change )
• these are detected by receptors and information passes along cells (called neurones)
• as electrical impulses to the CNS

Question 13

Name the two parts of the central nervous system

Answer 13

• brain

- spinal cord

Question 14

What does the CNS coordinate?

Answer 14

coordinates the response of an effector which may be muscle contracting or glands secreting hormones

Question 15

Put these in the correct order: receptor, stimulus, response, coordinator, effector

Answer 15

stimulus 🡪 receptor 🡪 coordinator 🡪 effector 🡪 response

Question 16

What is the role of the sensory neurone?

Answer 16

carrying electrical impulses from the receptor to the CNS

Question 17

What is the role of the relay neurone?

Answer 17

connecting the sensory neurone to the motor neurone in the CNS

Question 18

What is the role of the motor neurone?

Answer 18

carrying electrical impulses from the CNS to an effector

Question 19

What is a synapse?

Answer 19

the gap between 2 neurones

Question 20

Describe what happens at the synapse

Answer 20

• when an impulse reaches the end of a neurone a chemical (neurotransmitter) is released across the gap
• the chemical then diffuse across the synapse
• when the chemical reaches the next neurone it starts another impulse

Question 21

What is a reflex action?

Answer 21

an automatic and rapid action, they don’t involve the conscious part of the brain

Question 22

Why are reflex actions important?

Answer 22

they protect the body from injury

Question 23

What is the path that a reflex action takes called?

Answer 23

• reflex arc

Question 24

Recall the pathway of the reflex arc

Answer 24

receptor 🡪 sensory neurone 🡪spinal cord 🡪 motor neurone 🡪 effector

Question 25

What does the pancreas do?

Answer 25

- it produce and secretes the hormones(insulin and glycagon) - monitors and controlled the blood glucose concentration

Question 26

Name the hormones that the pancreas releases

Answer 26

- insulin | - glycagon

Question 27

What does insulin and glycagon do to the blood glucose concentration?

Answer 27

the hormones regulates the bgc as insulin reduces the concentration and glycagon increase the concentration of glucose in the blood

Question 28

What happens to the glucose in the blood when insulin is released?

Answer 28

- when bgc is too high the pancreas release insulin - the glucose moves from the blood into the cells - the liver & muscle cells converts the excess glucose into glycogen

Question 29

Describe the role of glucagon in the regulation of glucose?

Answer 29

- when bgc is too low the pancreas releases glycagon - and it stimulates the liver & muscle cells - to convert glycogen into glucose

Question 30

What is diabetes?

Answer 30

is a conditions that causes a person's blood glucose level to become too high

Question 31

Which type of diabetes is caused when the pancreas fails to produce enough insulin?

Answer 31

type 1

Question 32

What happens when there's a lack of insulin in type 1?

Answer 32

an uncontrolled high blood glucose level

Question 33

Which type of diabetes is caused when the body cells no longer respond to insulin?

Answer 33

type 2

Question 34

What is the 2 main risk factors of type 2?

Answer 34

- obesity | - old age

Question 35

State how Type 1 diabetes is treated

Answer 35

- insulin therapy - insulin being injected when blood glucose levels are too high - controlling carbohydrates in the diet - regular exercise

Question 36

State how Type 2 diabetes is treated

Answer 36

- controlling carbohydrates in the diet | - regular exercise

Question 37

What is bgc an example of ?

Answer 37

- an example of negative feedback | - this ensure any control system changes is reversed and returned back to the set level

Question 38

Explain 3 reasons why its important to control blood glucose level?

Answer 38

- glucose is a fuel for respiration - if bgl are low = organism cannot meet its energy demand - if bgl are high = impacts on osmosis by affecting concentration gradients