D3.3 Homeostasis

Question 1

What is the positive feedback?

Answer 1

moves further from the original level (promoting the change)

Question 2

What is the negative feedback?

Answer 2

it works towards stability (reducing the change)

Question 3

What is homeostasis?

Answer 3

maintainance of stable internal conditions using negative feedback loops

Question 4

What are exocrine glands in pancreas?

Answer 4

they release digestive enzymes through openings (ducts)

Question 5

What are endocrine glands?

Answer 5

they release hormones directly into a bloodstream

Question 6

Which cells secrete glucagon?

Answer 6

alpha-cells of the islets of Langerhans

Question 7

Which cells secrete insulin?

Answer 7

beta-cells of the islets of Langerhans

Question 8

What are pancreatic islets (endocrine cells)?

Answer 8

they are clusters of cells that produce insulin and glucagon

Question 9

What is the role of insulin?

Answer 9

it stimulates glucose uptake in response to high glucose levels

Question 10

What’s the role of glucagon?

Answer 10

it stimulates the liver to release glucose in response to low sugar levels

Question 11

Which tissue responds to insulin and take up glucose?

Answer 11

liver cells, muscles and fat tissue

Question 12

How the excess glucose is stored?

Answer 12

glucose is stored as glycogen in liver and muscles cells, or as fat in the fat tissue

Question 13

Which tissue does glucagon promote and what happens in them?

Answer 13

liver and fat tissue breaks down stored glycogen and lipids and release to the bloodstream

Question 14

What is thermoregulation?

Answer 14

process when body maintains stable temperature no matter the external environment

Question 15

Where are processes of temperature control centered?

Answer 15

hypothalamus

Question 16

What’s the role of hypothalamus?

Answer 16

-it receives the signals from peripheral thermoreceptors
-it stimulates pituitary gland to release TSH to stimulate thyroid gland

Question 17

What’s the role of the thyroid gland?

Answer 17

it produced hormone thyroxin

Question 18

What’s the role of thyroxin?

Answer 18

it increases metabolic rate of body cells and produce more heat

Question 19

List mechanism that can regulate body temperature when it’s cold (3)

Answer 19

-skeletal muscle contractions (shivering)
-muscles in the skin contracts to make hair stand up to increase insulation
-vasoconstriction

Question 20

What is vasoconstriction? What’s the function?

Answer 20

narrowing of blood vessels, keeps warm blood closer to vital organs

Question 21

What is the name of thermoreceptors on skin?

Answer 21

peripheral

Question 22

What is the name of thermoreceptors inside the body?

Answer 22

central

Question 23

How body communicate to produce more heat (with thyroxine)?

Answer 23

1. skin thermoreceptors stimulate hypothalamus
2. hypothalamus stimulates the pituitary gland.
3. pituitary gland releases thyroid stimulating hormone (TSH)
4. TSH stimulates the thyroid gland
5. thyroid gland produces thyroxine
6. thyroxine increases metabolic rate

Question 24

List mechanisms the body use to maintain normal temperature when is cold and when is hot

Answer 24

Question 25

What is uncoupled respiration?

Answer 25

occurs in brown adipose tissue, full of mitochondria, breakdown of stored fat that releases heat but it doesn't produce ATP

Question 26

What is osmoregulation?

Answer 26

control of the balance between water and solutes

Question 27

What are the functions of the kidney?

Answer 27

- osmoregulation - excretion - production of hormones - blood pressure control

Question 28

What are nephrons and what is their function?

Answer 28

unit of the kidney, they: - filter blood - reabsorb useful substances - excrete products in the form of urine

Question 29

What are the elements of structure of a kidney?

Answer 29

- cortex - medulla - renal artery, vein and pelvis - ureter

Question 30

What is glomerulus and what is it's function?

Answer 30

capillaries in Bowman's capsule that filter blood

Question 31

What is Bowman's capsule and what is it's function?

Answer 31

surrounds glomerulus and initially filtrates blood forming filtrate

Question 32

What are the three main functions of nephrons?

Answer 32

- ultrafiltration - reabsorption - secretion

Question 32

What is proximal convoluted tubule and what is its function?

Answer 32

loop-like section of a nephron where water, nutrients and salts are reabsorbed

Question 33

Why and which arteriole in kidney is bigger than the other?

Answer 33

afferent is larger to create high pressure and for molecules out of the glomerulus

Question 34

Where does selective reabsorption happen?

Answer 34

in proximal convulated tubule

Question 35

What are the adaptations of proximal convulated tubule?

Answer 35

- microvilli that increase surface area - lots of mitochondria to produce ATP for active transport

Question 36

How blood is transported in nephrons?

Answer 36

afferent arteriole brings blood to neuphron, forms capillaries and exits via efferent arteriole

Question 37

Which molecules are not reabsorbed?

Answer 37

- urea - *salt - *water - toxins

Question 38

What's the role of loop of henle?

Answer 38

maintains high solute concentration in medulla

Question 39

What's the two sections of loop of henle?

Answer 39

- descending limb - ascending limb

Question 40

What's the role of descending limp?

Answer 40

it reasorbs water through aquaporins due to high solute concentration in medulla that supports osmosis

Question 41

What's the role of ascending limb

Answer 41

it reabsorbs sodium ions from filtrate via active transport

Question 42

What is ADH?

Answer 42

hormone released by pituitary that increases permeability of the collecting duct