Endocrine System I

Question 1

Define glands

Answer 1

Organs derived from epithelial cells, specialised in synthesis/secretion

Question 2

Define exocrine glands

Answer 2

Secrete products into ducts which lead into external environment eg skin/lumen

Question 3

Define endocrine glands

Answer 3

Secrete hormones into interstitial fluid, diffuse into blood

Question 4

What are the 2 major systems regulating cell communication?

Answer 4

Nervous system - Autonomic NS, Somatic NS

Endocrine system

Question 5

Describe the endocrine system

Answer 5

Consists of endocrine glands that secrete hormones, vital adaptation to changes in internal/external environment

Question 6

Define hormone

Answer 6

Chemical substance secreted into blood in very small amounts from specialised cells/organs

Question 7

Define target cells

Answer 7

Cell respond to specific hormone

Question 8

Define receptor

Answer 8

Certain proteins in target cells that specifically recognise/bind to messenger

Question 9

Describe hormones in the endocrine system

Answer 9

Release from endocrine gland into blood, transported in blood to target

Question 10

Describe neurohormones in the endocrine system

Answer 10

Released from neuron into blood, transported in blood to target, acts similar to hormones

Question 11

Define autocrine

Answer 11

Act through diffusion onto same cells which produce it

Question 12

Define paracrine

Answer 12

Move by diffusion, act on adjacent cells

Question 13

Describe the journey through the organs of the endocrine system

Answer 13

Primary: Pineal, hypothalamus, pituitary, thyroid, parathyroid, thymus, adrenal, pancreas, ovaries/testes
Secondary: Heart, stomach, liver, kidneys, small intestines, skin

Question 14

Describe the secreted products from each primary endocrine organ

Answer 14

Pineal - Melatonin
Hypo - Peptide Hs
Thyroid - T3, T4
Parathyroid - PTH
Thymus - Thymopoietins, thymosins
Adrenal > Cortex, medulla
Pancreas - Glucagon, insulin
Gonads - Oestrogen, progesterone, testosterone

Question 15

Describe the secreted products from each secondary endocrine glands

Answer 15

Heart - ANP (red blood volume, pressure, Na)
GI - Gastrin, serotonin
Liver - Somatomedins
Kidneys - Eryhtropoietin
Skin - Calcitriol, Vit D

Question 16

What are the different types of hormones in the endocrine system?

Answer 16

Amine (hydrophillic), peptide (hydrophollic), steroid (lipophillic)

Question 17

Describe amine hormones

Answer 17

Simplest, small molecules, similar structure to AA
Eg catecholamine (dop), thyroid hormones (T3), both derived from AA tyrosine

Question 18

Describe peptide hormones

Answer 18

Peptides/proteins hormones

Eg Pancreas’ insulin

Question 19

Describe steroid hormones

Answer 19

Lipids from cholesterol

Eg aldosterone from adrenal cortex

Question 20

Describe the secretion and transport in the blood

Answer 20

Peptides/Catecholamine (hydrophillic) - Secretion by exocytosis free in plasma
Steroids/thyroid hormones - Secretion by simple diffusion, protein-bound in plasma

Question 21

Describe the action of hydrophillic hormones

Answer 21

Binds to receptors on plasma membrane at:
Channel-linked receptors (LG ion channels)
Enzyme-linked receptors
G-protein-linked receptors (slow LG channels, G-protein-regulated enzymes, second messengers)

Question 22

Describe the lipophillic hormones

Answer 22

Binds to receptors intracellular at:
Receptors located in cytosol/nucleus
Synthesis of specific proteins is altered

Question 23

Describe ADH in terms of posterior pituitary

Answer 23

Dec water loss from kidney
Constriction of peripheral blood vessel
Secretion stimulated by: Water deficit, Dec BP

Question 24

Describe oxytocin in terms of posterior pituitary

Answer 24

Acts on smooth muscle cells in breast/uterus

Stimulated by suckling and uterine contractions

Question 25

Describe the hormones from anterior pituitary

Answer 25

Growth hormone - Metabolism
Thyroid stimulating hormone - Stimulates thyroid gland to secrete T4/T3
Adrenocorticotropic hormone - Stimulates adrenal cortex to secrete cortisol
Prolactin - Stimulates breasts development and milk production
Gonadotropic hormone - FSH and LH stimulates gonads to secrete gonad hormones

Question 26

Name some hypothalamus hormones

Answer 26

GHRH, TRH, CRH, GnRH, PRF, SS, DA