The Endocrine System

Question 1

Key Features

Answer 1

-The endocrine system works alongside the nervous system to control vital functions in the body through the action of hormones.
-It works more slowly than the nervous system but has widespread and powerful effects

Question 2

Glands

Answer 2

-Glands are organs in the body that produce hormones
-The key endocrine gland is the pituitary gland, located in the brain. It is called the ‘master gland’ because it controls the release of hormones from all the other endocrine glands in the body

Question 3

Hormones

Answer 3

Hormones

-Hormones are secreted in the bloodstream and affect any cell in the body that has a receptor for that particular hormone
-For example, thyroxine produced by the thyroid gland affects any cells in the heart and also cells throughout the body which increase metabolic rates. This in turn affects growth rates.

Question 4

Endocrine system + ANS working together

Answer 4

-Stressor perceived by hypothalamus- activates the pituitary
-The SNS is now aroused
-Adrenaline (stress hormone) is released from adrenal medulla into the bloodstream. This delivers the aroused state causing changes in target organs in the body. This is the fight or flight response.
-Immediate and automatic- happens the instant a threat is perceived.
-PNS (rest and digest) takes over once the threat has passed. Returns the body to its resting state. This acts as a ‘break’ and reduces the activities of the body that were increased by the actions of the sympathetic branch.

Question 5

Sympathetic State

Answer 5

-Increases heart rate
-Increases breathing rates
-Dilates pupils
-Inhibits digestion
-Inhibits saliva production
-Contracts rectum

Question 6

Parasympathetic State

Answer 6

-Decreases heart rate
-Decreases breathing rate
-Constricts pupils
-Stimulates digestion
-Stimulates saliva production
-Relaxes rectum