B3.3 - Maintaining Internal Environment

Question 1

When too cold…

Answer 1

• affects Enzyme reactions
• rate of reactions slow down
• body reaction stops
• reduces blood flow to extrémités
• Respiration doesn’t release energy
• Cells begin to die

Question 2

When too hot…

Answer 2

Enzymes denature
Body reactions do not occur
Cells begin to die

Question 3

How is body temp controlled

Answer 3

Through thermoregulatory centre in your brain

Question 4

What does the thermoregulatory centre do?

Answer 4

Relies on signals received from receptor cells from skin (external) and and from internal receptors (internal blood). When change felt, brain causes different parts to respond by sending impulses to effectors. Returning body temp back to normal

Question 5

Physical changes in hyperthermia

Answer 5

Body hairs lie flat - preventing insulating layer
Sweat glands produce sweat - water evaporation releases heat energy
Blood vessels widen (vasodilation) - increases blood flow increasing heat loss by radiation

Question 6

Physical changes in hypothermia

Answer 6

Body hairs lift off skin - creating insulating layer of air to preserve heat
Sweat glands do not produce sweat
Blood vessels narrow (vasoconstriction) - reducing blood flow reducing heat loss
Start shivering - muscles contract and relax fast - cells respire quicker and give extra heat energy

Question 7

What is insulin?

Answer 7

Released by pancreas to go to the liver by blood flow and helps liver turn glucose into glycogen by breaking them down (enzyme controlled reactions)

Question 8

Too much glucose in blood

Answer 8

Eat a meal - blood sugar levels increase
Pancreas releases insulin
Liver converts glucose into glycogen

Question 9

Too little glucose in blood

Answer 9

Exercise - blood sugar levels decrease
Pancreas releases glucagon
Liver converts glycogen into glucose

Question 10

Type 1 diabetes

Answer 10

Genetic condition
Cannot produce insulin - own immune system has destroyed pancreatic cells
Gets injections

Question 11

Type 2 diabetes

Answer 11

Due to health life
Cannot effectively use or produce insulin
So, they regulate carb intake (diet) and exercise regularly

Question 12

What does urine contain

Answer 12

Excess salts, excess water, urea

Question 13

How urine produced?

Answer 13

Liver produces urea
Renal artery - brings blood contains urea and other waste to kidney
Ureter - tube through which urine passa from kidney to bladder
Goes to bladder where ring muscle opens and closes
Passes though urethra tube

Question 14

Capsule

Answer 14

Outer membrane helping to maintain shape and protect

Question 15

Cortex

Answer 15

Outer part of the kidney

Question 16

Medulla

Answer 16

Inner part of kidney

Question 17

Ultrafiltration

Answer 17

Blood enter kidney under high pressure to glomerulus
Contains knot of capillaries
High pressure forces small molecules like sugar water and salt out

Question 18

Sélective reabsorption

Answer 18

Some water and salt may be needed from body
Filtrate passes through loop of henlé - reabsorption
Waste sol collects in bladder

Question 19

If water concentration is too high

Answer 19

Pituitary gland releases less ADH
tubules reabsorb less water
More urine is produced (dilute)

Question 20

If water concentration is too low

Answer 20

Pituitary gland releases more ADH
tubules reabsorb more water
Less urine produced (concentrated)

Question 21

Lack of water in body

Answer 21

Triggers thirst response
Produces less urine
Dehydration

Question 22

Too much water in body

Answer 22

Produces more urine
Cells may burst (lysis)
Muscle cramps
Seizures

Question 23

Hypertonic solutions

Answer 23

Contain high levels of sugar and glucose - used by short distance runners

Question 24

Hypotonic solutions

Answer 24

Contain low levels of sugar/more water based - long distance fro rehydration

Question 25

Isotonic solutions

Answer 25

Ion concentration equal to those in in blood plasma - high energy and long distance

Question 26

Nephron structure

Answer 26

• glomerus
• bowman’s capsule
• proximal convoluted tubule
• loop of henlé
• second coil/ distil convoluted tubule
• collecting duct