the endocrine system

Question 1

what is the endocrine system?

Answer 1

one of the body’s major information systems that instructs glands to release hormones directly into the bloodstream which are carried towards target organs in the body

Question 2

how does the endocrine system communicate?

Answer 2

via chemicals

Question 3

what is the endocrine system like compared to the nervous system?

Answer 3

• E works alongside N to control vital functions in body
• E acts more slowly than N
• E has more widespread and powerful effects than N

Question 4

what is a gland?

Answer 4

an organ in the body that synthesises substances such as hormones

Question 5

what are hormones?

Answer 5

chemical substances that circulate in the bloodstream and only affect target organs

Question 6

describe the production and effect of hormones

Answer 6

• produced in large quantities
• disappear quickly
• effects are very powerful

Question 7

what does thyroxine, produced from the thyroid gland, affect?

Answer 7

1. cells in the heart (increases heart rate)
2. cells throughout the body, increasing metabolic rates which in turn affects growth rates

Question 8

what is the pituitary gland?

Answer 8

• key endocrine gland
• located in the brain
• ‘master gland’: controls release of hormones from all other endocrine glands in the body

Question 9

what is the flight or fight response?

Answer 9

• way an animal responds when stressed
• body becomes physiologically aroused in readiness to fight an aggressor, or to flee

Question 10

what happens during a stressful event?

Answer 10

1. stressor is perceived
2. hypothalamus activates pituitary gland
3. activity is triggered in sympathetic branch of NS
4. ANS changes from normal resting state (parasympathetic) to physiologically aroused state (sympathetic)

the endocrine system and the autonomic nervous system work in parallel with one another

Question 11

what is adrenaline?

Answer 11

• stress hormone
• released from adrenal medulla in adrenal gland
• part of body’s immediate stress response system

Question 12

what does adrenaline do?

Answer 12

it triggers physiological changes in the body (eg. increased heart rate) which creates the physiological arousal necessary for the fight or flight response

Question 13

where does adrenaline have a strong effect? (3)

Answer 13

cells of the cardiovascular system
- stimulates heart rate
- contracts blood vessels
- dilates air passages

Question 14

biological changes associated with the sympathetic state (6)

Answer 14

• increased heart rate
• increased breathing rate
• dilated pupils
• inhibited digestion
• inhibited saliva production
• contracted bladder

Question 15

what are some reasons for the biological changes associated with the sympathetic state?

Answer 15

• increased heart/breathing rate for increased oxygen intake for respiration which releases energy
• dilated pupils to allow more light to be taken in through the eyes so more can be seen
• resources are diverted away from non-essential functions eg. digestion

Question 16

what are some biological changes associated with the parasympathetic state? (6)

Answer 16

• decreased heart rate
• decreased breathing rate
• constricted pupils
• stimulated digestion
• stimulated saliva production
• relaxed bladder

Question 17

what is the ‘rest and digest’ response?

Answer 17

when parasympathetic branch of ANS reduces activities that were increased by actions of sympathetic branch so body is returned to resting state