Endocrine system

Question 1

what is the endocrine system made up of?

Answer 1

a number of glands that secrete hormones directly into the blood stream.

Question 2

what is the purpose of the endocrine system?

Answer 2

is to regulate a range of bodily functions using hormones.

Question 3

where are islets of langerhans found and what do they contain?

Answer 3

they are a group of cells in the pancreas that contain hormone producing cells.

Question 4

what cells are found in the islets of Langerhans?
list 3

Answer 4

alpha, beta and delta cells

Question 5

what does the alpha cells produce?

Answer 5

glucagon

Question 6

what does the beta cells produce?

Answer 6

insulin

Question 7

what does the delta cells produce?

Answer 7

glucagon and inhibitors

Question 8

what are the 2 hormones released by the pancreas?

Answer 8

insulin and glucagon

Question 9

1) what does insulin cause and where is it found?
2) what does it convert? from ____ to ___.

Answer 9

1) glycogenesis in the liver
2) conversion of soluble glucose to insoluble glycogen

Question 10

1) what does glucagon cause and where is it found?
2) what does it convert? from ____ to ___.

Answer 10

1) glycogenolysis in liver
2) conversion of insoluble glycogen to soluble glucose.

Question 11

definition of homeostasis?

Answer 11

the maintenance of the internal environment within restricted limits.

Question 12

definition of negative feedback?

Answer 12

the detection and response when conditions change from the ideal or set point and return the condition to this set point. it is a continuous cycle.

Question 13

what are the 2 different levels of blood glucose control?

Answer 13

high and low

Question 14

what happens to high blood glucose in the body?
list 4

Answer 14

1) detected by beta cells in the pancreas.
2) b cells respond by secreting insulin by exocytosis.
3) insulin is then transported around the body in the bloodstream.
- insulin stimulates the uptake of glucose by muscle cells, fat cells and the liver.
- insulin stimulates glycogenesis in liver cells converting soluble glucose to insoluble glycogen.
4) this lowers the concentration of glucose in the blood.

Question 15

what happens to the body when blood glucose levels are low?
list 5

Answer 15

1) detected by alpha and beta cells in the pancreas.
2) b cells respond by stopping insulin secretion.
3) alpha cells respond by secreting glucagon by exocytosis.
4) glucagon is then transported around the body in the bloodstream.
- the reduction of insulin means liver cells and muscle cells uptake less glucose.
- glucagon stimulates glycogenolysis of insoluble glycogen to soluble glucose in liver cells.
5) this rises the concentration of glucose in the blood.

Question 16

what is the main role of the kidney in our body?

Answer 16

it is to remove waste and extra fluid from the blood.

Question 17

what label are included in the diagram of a kidney?
in order list 5

Answer 17

Cortex, medulla, renal artery, renal vein and ureter.

Question 18

what is the main unit of a kidney called?

Answer 18

the nephron

Question 19

where is the nephron found?

Answer 19

is partially in the cortex and partially in the medulla.

Question 20

how does the production of urine occur and what is this process called?
list 10

Answer 20

1) blood enters the kidney through the renal artery.
2) the blood travels through the afferent arteriole to the glomerulus.
3) as the glomerulus is entered the capillaries get narrower
- this increases the pressure on the blood.
4) the glomerulus sits inside a cup called the bowman’s capsule.
5) between the glomerulus and the bowman’s capsule are two cell layers.
6) the endothelial cell layer of the capillary is perforated by tiny holes.
7) the epithelial cell layer of the bowman’s capsule has finger-like projections called podocytes.
8) as blood travels through the narrow capillaries of the glomerulus the following small molecules are forced out due to the high pressure:
- amino acid
- water
- glucose
- urea
- inorganic ions
9) they pass through gaps between the podocytes into the bowman’s capsule.
10) the liquid formed is the glomerular filtrate.

• this process is called ultrafiltration.

Question 21

what is ultrafiltration —-> definition and where does it happen.

Answer 21

happens in the bowman’s capsule. the non-specific filtration of the blood under high pressure occurs in the bowman’s capsule of the nephron.

Question 22

when the production of urine occurs –> ultrafiltration, what happens to the blood cells and platelets and how are they carried away?

Answer 22

they remain in the blood as they are too large to fit through the gaps. they are carried away from the glomerulus by the efferent arteriole.

Question 23

what happens to the filtrate after ultra-filtration has occurred?

Answer 23

the filtrate travels along the proximal convoluted tubule. in the proximal convoluted tubule, selective reabsorption occurs.

Question 24

what is reabsorbed in the proximal convoluted tubule?
list 5

Answer 24

1) all glucose
2) amino acids
3) vitamins
4) inorganic ions
5) some urea is also reabsorbed by diffusion

Question 25

how does selective reabsorption occur? list 6

Answer 25

1) sodium-potassium pumps in the lining of the proximal convoluted tubule pump Na+ ions into the blood capillaries. 2) this lowers the Na+ concentration in the epithelial cells. 3) this creates a concentration gradient between the filtrate and the cell. 4) sodium ions bind to co-transport proteins with a solute molecule. 5) the co-transport protein then changes shape releasing both the solute and the sodium ions into cells, down the Na+ concentration gradient. 6) the solutes are then able to diffuse into the blood normally through channel proteins.

Question 26

what are the adaptations of proximal convoluted tubule. list 4

Answer 26

1) has many microvilli - increases surface area 2) has many co-transport proteins - needed for facilitated diffusion of solutes 3) has many mitochondria - needed to produce ATP for the sodium-potassium pump to use in active transport 4) has tightly packed cells - so no fluid can pass between cells.

Question 27

what happens after selective reabsorption to the filtrate? list 7

Answer 27

1) the remaining filtrate passes down the loop of Henle. 2) this is where salt and water are reabsorbed. 3) the salt diffuses out of the filtrate into the tissue fluid of the medulla. 4) this increases the salt concentration of the medulla. 5) as the salt conc in the medulla has increased it manages to create a water concentration gradient. 6) the filtrate has a higher water conc than the surrounding medulla tissue. 7) as the remaining filtrate passes through the distal convoluted tubule and collecting duct water passes into the tissue by osmosis.

Question 28

what is osmoregulation ---> definition

Answer 28

this is how we maintain the normal concentration of bodily fluids by altering the amount of water released.

Question 29

what hormone controls osmoregulation?

Answer 29

ADH

Question 30

what happens if blood water concentration is high? list 4

Answer 30

1) the water level is detected by osmoreceptors in the brain's hypothalamus. 2) less ADH is secreted by the posterior lobe of the pituitary gland. 3) this causes the membranes of the dct and collecting ducts to become less permeable to water. 4) so less water is re-absorbed by osmosis.

Question 31

what happens if blood water concentration is low? list 4

Answer 31

1) the water level is detected by osmoreceptors in the hypothalamus. 2) more ADH is secreted by the posterior lobe of the pituitary gland. 3) this causes the membranes of the dct and collecting ducts to become more permeable to water. 4) so more water is re-absorbed by osmosis.

Question 32

after osmoregulation occurs, what is the remaining filtrate consist of and where does it pass down to? list 3

Answer 32

1) excess water 2) urea 3) excess vitamins and minerals this then gets passed down the collecting duct into the ureter and is transported to the bladder.

Question 33

what is the order of the production of urea? list

Answer 33

1) ultrafiltration 2) selective reabsorption 3) osmoregulation 4) then gets passed down the collecting duct into the ureter and is transported to the bladder.