body systems and homeostatic regulation

Question 1

what is hyperthyroidism?

Answer 1

when the thyroid gland produces too much thyroxine.

Question 2

how does the thyroid produce thyroxine?

Answer 2

it produced thyroxine in response to the thyroid-stimulating hormone (TSH) from the pituitary gland.

Question 3

what does thyroxine affect? list 3 things it does to the body

Answer 3

the increase of thyroxine production in the body leads to an increased basal metabolic rate

• increased body temp
• weight loss
• increased appetite
• sensitivity to heat and sweating more
• relative insensitivity to cold conditions

Question 4

what may cause hyperthyroidism?

Answer 4

• nodules (small swelling/aggregation in the body)
• genetic factors
• Grave’s disease

Question 5

why does Grave’s disease cause hyperthyroidism?

Answer 5

because it is an autoimmune disease, the immune system cells (antibodies called immunoglobulin) target the thyroid gland, which signal to the body to produce more thyroxine

Question 6

management of hyperthyroidism

Answer 6

• surgical removal of part of the thyroid gland
• anti-thyroid medication - interferes with ability to take iodine from blood, which is an essential component of thyroxine

Question 7

what is type one diabetes?

Answer 7

a chronic autoimmune disease where the beta-cells of the pancreas produce very little-no insulin, which affects the regulation of blood glucose levels.

Question 8

how is insulin released?

Answer 8

it is released from the Islets of Langerhans from its beta cells which is found in the pancreas.

Question 9

what does insulin do?

Answer 9

insulin lowers the blood glucose concentration
insulin binds to cells, which attaches glucose transporters onto the cells. This increases the amount of glucose being absorbed by facilitated diffusion.

Question 10

what happens if there isn’t enough insulin released? what are some symptoms?

Answer 10

If not enough insulin is released into the bloodstream, the blood glucose concentration to remain high (hyperglycaemia)
- can cause glucose to found in urine
- increased urination
- extreme hunger/thirst
- fatigue

Question 11

why is fatigue a symptom of diabetes?

Answer 11

when blood glucose is high, the body isn’t taking in the glucose as energy

Question 12

why is increased urination a symptom of diabetes?

Answer 12

when the blood has high levels of glucose, it is a hypertonic solution, so water from the cells releases to level out the concentration gradient. This leads to more water entering the bloodstream and entering the kidneys, which leads to more urination. This is also why thirst is a symptom of diabetes

Question 13

why is finding glucose in urine a sign of diabetes?

Answer 13

as there is an increased about of glucose, the carrier proteins in the kidneys aren’t able to deal with high levels of glucose, leading to traces of glucose in urine.

Question 14

negative feedback

Answer 14

body changing to match the needs of the stimulus

Question 15

negative feedback order

Answer 15

stimulus, receptor, modulator, effector, response

Question 16

negative feedback for high blood glucose levels

Answer 16

stimulus - increased blood glucose levels
receptor - stimulus is detected by the islet cells of the pancreas

modulator - beta cells are stimulated to release insulin into the bloodstream. alpha cells decrease glucagon release

effector - all body cells are affected

response - increased uptake of glucose into cells. liver increased glucose uptake and stored are glycogen.

Question 17

negative feedback for low blood glucose levels

Answer 17

stimulus - decreased blood glucose levels

receptor - stimulus is detected by the islet cells of the pancreas

modulator - alpha cells are stimulated to release glucagon into the bloodstream. beta cells decrease insulin release

effector - liver cells, brain, digestive system

response - liver breaks down glycogen stores, which releases glucose into the blood.

Question 18

what is the difference between type 1 and type 2 diabetes?

Answer 18

type 2 is a lifestyle disease
cells in type two diabetes are insulin resistant which means that they don’t absorb glucose from the blood as usual.

Question 19

what is hyperglycaemia?

Answer 19

when there is too much blood glucose

Question 20

what is hypoglycaemia? what can cause it?

Answer 20

not enough glucose in the bloodstream. this can be caused by injecting too much insulin, exercise too much or don’t consume enough glucose

Question 21

why do ppl with type 1 not produce normal levels of glucagon? what does this mean for blood glucose when fasting?

Answer 21

In addition, because their alpha cells are impaired, people with type 1 diabetes don’t produce normal levels of glucagon,

meaning that they do not produce normal amounts of glucose via glycogenolysis in periods of fasting and their blood glucose level continues to fall.

Question 22

what is glucose?

Answer 22

the main source of energy for cells

Question 23

what is glucagon

Answer 23

hormone that is secreted by beta-cells when blood glucose levels are low

Question 24

what is glycogen?

Answer 24

chains of glucose that are stored in the liver for when there is low blood glucose levels

Question 25

what is osmoregulation?

Answer 25

the regulation of water in the bloodstream

Question 26

what receptors are involved in osmoregulation and where are they located?

Answer 26

The receptors are osmoreceptors in the hypothalamus

Question 27

stimulus response model for high water content

Answer 27

stimulus - high water content in the blood receptor - osmoreceptors (in the hypothalamus) detect the high water content which send signals to the pituitary gland modulator - (hypothalamus) the pituitary gland reduces amount of ADH released into the bloodstream effector - the kidneys reduce amount of water being absorbed into kidneys response - larger volumes of diluted urine is taken to the bladder

Question 28

stimulus response model for low water content

Answer 28

stimulus - low water content in the blood receptor - osmoreceptors in the hypothalamus detect the low water content which send signals to the pituitary gland modulator - (hypothalamus) the pituitary gland increases amount of ADH released into the bloodstream effector - the kidneys maintain blood water levels response - less amount of water is lost to urine (less concentrated)

Question 29

how is urine used in determining water levels?

Answer 29

urine concentration is determining of water content in the blood. If the urine is more concentrated, that means theres less water in the body, as less water makes it into urine. if the urine is diluted, this means that there is excess water in the blood, which is why there is dilution.

Question 30

what is the kidney?

Answer 30

the kidney is the site of where blood and water filtration occurs. it is also hormones are regulated.

Question 31

what brings blood in and out of the kidney?

Answer 31

the renal artery brings unfiltered blood to the kidney the renal vein brings the filtered blood back to the body

Question 32

what does the renal artery lead to?

Answer 32

the renal artery branches off into smaller capillaries, called nephrons.

Question 33

what are nephrons? where are they located?

Answer 33

nephrons are a functional unit of the kidney which filtrates pass through and where urine is produced. they are located in the cortex (outer) and the medulla (inner).

Question 34

what makes up the nephron?

Answer 34

bowmans capsule, proximal convoluted tubule, loop of Henle, distal convoluted tubule and collecting ducts

Question 35

what is the bowmans capsule?

Answer 35

it collects the filtered blood from the glomerulus, a unit inside of the bowmans capsule. fluids and solutes are filtered out at this point

Question 36

what is the proximal convoluted tube?

Answer 36

first site of water reabsorption and where water and salt is mainly absorbed. this is where glucose is also absorbed, almost all of it

Question 37

what is the loop of Henle?

Answer 37

it transfers the fluid from proximal tubule to the distal convoluted tubule. more water gets absorbed on the way down, and ions get absorbed on the way up

Question 38

what is the distal convoluted tubule?

Answer 38

final absorption in the nephron. the permeability of this area is dependent of a hormone stimulus (ADH).

Question 39

what is the collecting duct?

Answer 39

collects urine to pass it to the ureter, which leaves the kidney as urine.

Question 40

what does ADH do?

Answer 40

antidiuretic hormone - helps regulate the amount of water in the body and is released to absorb less water, which makes urine more concentrated