Human Endocrine System

Question 1

What is the human endocrine system?

Answer 1

Enables animals to respond to external changes and to control conditions inside their bodies

Question 2

What is a hormone?

Answer 2

Organic chemical substance secreted by an endocrine glad and carried in blood stream to target organs where it regulates metabolic reactions

Question 3

What is an endocrine and exocrine gland?

Answer 3

ENDOcrine:
Vascular, ductless gland that secretes hormones which are carried in the bloodstream to target organs
EXOcrine:
Secretions are carried in the ducts to where they are needed

Question 4

Hypothalamus

Answer 4

Part of the brain, above the pituitary gland
Secretes ADH (anti-diuretic hormone)

ROLE
osmoreceptors detect an increase in osmolarity in blood ➡️ releases ADH ➡️ conserve water (reabsorbed back into blood from kidneys collecting ducts)

Question 5

Pituitary gland

Answer 5

Attached to the hypothalamus
HORMONES
- TSH (stimulates thyroid gland = thyroxin)
- FSH (stimulates oogenesis and spermatogenesis)
- LH (stimulates ovulation and the formation of the corpus luteum)
- GH (promotes skeletal and muscular growth & stimulates the synthesis of proteins)
DISORDERS
- children (gigantism, pituitary dwarfism)
- adults (acromegaly)

Question 6

Thyroid gland

Answer 6

Secretes thyroxin 
FUNCTIONS 
- increases the basal metabolic rate 
- promotes normal heart and nervous system functions 
DISORDERS 
hypothyroidism
- adults = myxedema 
- children = cretinism 
Hyperthyroidism

Question 7

Pancreas

Answer 7

Exocrine (secretes pancreatic juice)
Endocrine (secretes Islets of Langerhans) 
- alpha cells: secrete glucagon 
- beta cells: secrete insulin 
FUNCTIONS 
Control blood sugar level
- insulin : lowers 
- glucagon : raises
DISORDERS 
diabetes

Question 8

Type 1 vs Type 2 Diabetes

Answer 8

TYPE ONE
- childhood
- pancreas doesn’t make insulin = glucose remains in the body
- no cure - controlled by daily insulin injections & testing blood sugar levels frequently
TYPE TWO
- adulthood
- influenced by lifestyle
- body produces less insulin / unable to use insulin correctly

Question 9

Adrenal glands

Answer 9

ADRENAL CORTEX
- aldosterone : increased reabsorptionof sodium ions = regulate electrolytic levels of body fluids
- cortisol : increases body’s ability to resist stress, ain’t-inflammatory and anti-allergic
ADRENAL MEDULLA
- adrenaline : prepares the body for actions (fight or flight)

Question 10

Gonads

Answer 10

OVARIES
- oestrogen : pubertal changes
- progesterone : during pregnancy (helps maintain endometrium)
TESTES
- testosterone : pubertal changes & sex drive