Endocrine system Term 1

Question 1

What is the function of the endocrine system? Why does it do this?

Answer 1

Influences the activity of cells by the release of chemical messengers known as hormones.
Keeps the environment inside the body constant

Question 2

What are the two types of glands in the body? Define them with an example.

Answer 2

Endocrine- secrete hormones into extracellular fluid that surrounds the cells that make up the gland (secretion passes into capillaries) e.g. pineal, kidneys, thyroid

Exocrine-secrete into ducts that carry secretion out of body or to a body cavity e.g. sweat glands, mucous glands, salivary glands

Question 3

What are hormones. What are it’s 3 different forms?

Answer 3

Specific, chemical messengers secreted by endocrine glands, that are transported throughout body by blood.
types: proteins, steroids, amines

Question 4

3 ways hormones effect enzyme activity? (it changes cells by doing so)

Answer 4

-activate certain genes in nucleus to produce certain enzymes/proteins
-change the shape/structure of an enzyme to switch on/off
-change the production rate of enz/protein by altering transcription or translation process

Question 5

What are proteins/amines hormones? are they soluble? What is their function
add examples

Answer 5

Water soluble-attach to protein receptor on membrane of cell.
-Activate secondary messenger
-Effect enzyme action in cytoplasm.
FSH, LH, insulin, oxytocin, glucagon, ADH, ACTH, prolactin, GH

Question 6

Examples of water soluble hormones

Answer 6

FSH, LH, insulin, oxytocin, glucagon, ADH, ACTH, prolactin, GH

Question 7

Why are receptor proteins specific? What is meant by the occurrence of saturation?

Answer 7

-receptor will bind with only one specific molecule
-receptor protein only works with binding molecule
-limited number of receptors in membranes of cells
-therefore, there is variation in sensitivities of cells, to hormones and other substances

when saturated no further increase in cell activity

Question 8

Define process of enzyme cascade and amplification
(movement of water soluble hormones)

Answer 8

-water sol. hormones interact w/ receptors on cell membrane surface
-receptors use secondary messenger (cyclic AMP) to diffuse through membrane and trigger other enzymes
-other enzymes activate more (different + increasing numbers of enzymes)
-cell carries out specific functions because of the final enzymes being activated
-small stimulus can produce large effect i.e. one hormone=many enzymes

Question 9

Define steroid hormones and their function. Add some examples

Answer 9

Lipid soluble. combine w/ receptor protein within cell
-control gene expression
e.g. sex steroids, corticosteroids, thyroxine

Question 10

Example of lipid soluble steroids

Answer 10

testosterone, progesterone, cortisol, aldosterone, thyroxine, oestradiol

Question 11

Define process of mechanism for steroid hormones
(movement of lipid soluble hormones

Answer 11

1. water insol. hormone enters once released into blood binds to transport protein to travel through bloodstream (cant dissolve)
2. at target cell, detaches and diffuses across phos.lipid bilayer membrane and enters nucleus and combines w/a receptor
3. receptor-hormone complex activates transcripts of gene controlling protein formation
4. inhibiting transcription=increase mRNA (or organelle in cyto.) causes a protein to be translated
5. resulting in protein synthesis
6. slower/longer lasting response than protein hormones

Question 12

Define hypothalamus and it’s hormones, target organ and effects

Answer 12

Regulates body temperature, water balance, heart rate, or increase/decrease secretions from other glands
-Secretes inhibiting/releasing factors into blood vessels to anterior pituitary
- pass hormones in vesicles down axon terminal to store in posterior, secreted when impulses down nerve fibres
target organs: uterus, mammary glands and kidneys
hormones: OT and ADH stored in posterior pit gland

Question 13

Define pituitary gland and function.

Answer 13

Master gland. Attached to hypothalamus by infundibulum. It regulates activity of endocrine glands that it produces in it’s two parts: anterior and posterior

Question 14

Define anterior lobe of P-gland and it’s hormones, target organ and effects

Answer 14

Secrete tropic hormones into surrounding blood vessels
-act on other endo-glands to grow/secrete hormones
-controlled by releasing/inhibiting factors secreted from hypothalamus via blood vessels
target cell/organs: gonads, all cells thyroid gland, adrenal cortex, mammary glands
-attached to hypothal by vasculature in infundibulum

Question 15

What hormones are released by the anterior lobe?

Answer 15

gonadotropins (FSH and LH)
-follicle stimulating hormone
-luteinizing hormone
-growth hormone
-thyroid stimulating hormone
-adrenacorticotropic hormone
-prolactin

Question 16

Function of FSH

Answer 16

follicle stimulating hormone
maturation of ovarian follicles and production of sperm
target organ: ovaries and testes

Question 17

Function of LH

Answer 17

luteinising hormone
ovulation and maintenance of corpus luteum
secretion of testosterone
target organ: ovaries and testes

Question 18

Function of growth hormone

Answer 18

protein synthesis, growth of body/skeleton, maintains organ size once maturity reached
target organ: all cells

Question 19

Function of thyroid stimulating hormone

Answer 19

stimulate hormone production from thyroid gland
target organ: thyroid gland

Question 20

Function of adrenocorticotropic hormone

Answer 20

controls production/release of hormones from adrenal glands/cortex
target organ: adrenal cortex

Question 21

Function of prolactin

Answer 21

initiates and maintains milk secretions
target organ: mam glands

Question 22

Define posterior lobe of P-gland and it’s hormones, target organ and effects. How does hormone transfer from hypothalamus occur between P-gland?

Answer 22

stores and releases oxytocin+antidiuretic hormones manufactured in hypothalamus
-hormones move down axon terminals in vesicles to be stored
-nerve impulses sent through hypothal./initiate release into blood stream
-attached to hypothal by nerve fibres
target: Uterus, Mammary Glands, kidneys

Question 23

Function of oxytocin

Answer 23

-stimulates contraction of muscles of uterus
-stimulates contraction of cells in mammary glands to secrete milk
target organ: uterus and mam glands

Question 24

Function of antidiuretic hormone

Answer 24

cause kidneys to remove water from urine (return to bloodstream)
-retain fluid within body
target organ: kidneys

Question 25

Define function of pineal gland and it’s hormones, target organ and effects
what occurs following puberty
what stimulates/inhibits it’s activity

Answer 25

reduces in size following puberty
-release melatonin which controls sleep
-stimulated by darkness/inhibited by light
target organ: blood pressure/heart rate

Question 26

Define function of thyroid gland and it’s hormones, target organ and effects

Answer 26

Made of two lobes that lie on sides of trachea
-secrete and produce thyroxine and triiodothyronine using trapped iodine in food/water/amino acids in response to thyroid-stimulating hormone from pituitary
Thyroxine
-increase O2 consumption and metabolic rate
-controls release of energy and body temp.
target organ/cells: most

Question 27

Define function of parathyroid
Hormones secreted
Target organs

Answer 27

Usually 4.
-secrete parathyroid hormones (parathormone)
-increase calcium in blood and phosphate excretion in urine
target organs: bones/ kidneys

Question 28

Define function of thymus and it’s hormones, target organ and effects
What occurs after puberty?

Answer 28

begins to shrink after puberty.
secretes thymosin which influence maturation of T lymphocytes
target cells/organs=T lymphocytes

Question 29

Define structure of adrenal glands

Answer 29

two above kidney. Each has adrenal medulla inner) and ad.cortex (outer)

Question 30

Define function of adrena medulla and it’s hormones, target organ and effects.

Answer 30

produces adrenaline and noradrenaline
adren.- helps prepare body for reaction to a threatening situation e.g. sweat to cool body, dilate pupils, dig. system slows

nora.- increase rate/force of heartbeat e.g exercise, improves blood flow
target organs/cells= most body tissues

Question 31

Define function of adrenal cortex and it’s hormones, target organ and effects.

Answer 31

produces corticosteroids
aldosterone- act on kidneys to increase amount of sodium/decrease potassium in blood

cortisol-promotes normal metabolism and helps body withstand stress and repair damaged tissues
target organs/cells
aldosterone: kidneys
cortisol: most body cells

Question 32

Define function of pancreas and it’s hormones, target organ and effects

Answer 32

Endo
-regulate glucose levels in the blood by signaling the liver to store or release glucose as needed.
Hormones: Insulin helps the body absorb glucose from the bloodstream and use it for energy. Decrease blood glucose levels
Glucagon signals the liver to release glucose into the bloodstream when necessary, increasing glucose levels
target cells/organs:
insulin: most body cells
glucagon: liver, fat storage cells

Question 33

In depth review of function of insulin. What secretes it in pancreas?

Answer 33

From beta cells-decrease blood glucose by:
-accelerating transport of glucose from bloods into body cells (skeletal muscles)
-accelerating glycogenesis in liver/skeletal muscles
-stimulating protein synthesis (from glucose to protein)
-stimulating lipogenesis/fat storage

Question 34

In depth review of function of glucagon

Answer 34

from alpha cells-increase blood glucose levels by:
-stimulate glycogenolysis
-stimulate gluconeogenesis in the liver (new glucose molecules formed form amino acids and fats (broken down/lipolysis)
-inducing protein breakdown

Question 35

Define gonads. Hormones?

Answer 35

Sex organs (primary)
-secrete androgens, oestrogen and progesterone
target: uterus, mam glands, many tissues

Question 36

Function of androgens e.g. testosterone

Answer 36

male sex hormones responsible for development and maintenance of male sex characteristics and sperm production
target cells: many tissues

Question 37

Function of oestro and progesterone
Target organs

Answer 37

oestrogen: Regulate menstrual cycle via growth and repair of endometrium, and development/maintenance of sex characteristics
target organs: many tissues
progesterone: promotes endometrium growth to regulate menstrual cycle, prepares mammary glands for milk production
target organs: uterus and mammary glands

Question 38

What are some negative feedback hormone pairs examples

Answer 38

-increase insulin suppresses glucagon
-increase/decrease to blood sugar levels due to increase/decrease oxytocin

Question 39

Describe process of thyroid physiology
i.e. how hypothalamus causes hormone release from thyroid gland

Answer 39

1. Hypothalamus releases thyrotropin-releasing hormone (TRH) which stimulates pit. gland
2. pit. gland, releases TSH hormone stimulates thyroid
3. gland makes thyroid hormones T3 and T4
4. As both hormones made, they signal hypothalamus and pit. to stop stimulating i.e. T3 and T4 are adequate no more needs to be made