t5- homeostasis in humans

Question 1

what is body temp controlled by

Answer 1

thermoregulatory centre, which is in the hypothalamus in the brain
-it contains receptors sensitive to the temperature of blood

Question 2

what happens in the skin when we get too hot

Answer 2

-sweat glands in skin release more sweat
-the sweat evaporates, transferring heat energy from skin to environment

Question 3

what happens in blood vessels when we get too hot

Answer 3

-they get wider
-they also dilate, allowing more blood to flow through the skin

Question 4

what happens to skeletal muscles when we get too cold

Answer 4

-they contract rapidly, so we shiver
-these contractions need energy from respiration

Question 5

what happens to blood vessels when we get too cold

Answer 5

-get narrower
-they constrict, allowing less blood to flow through skin

Question 5

how does hair on skin help control body temp

Answer 5

-they lie flat when we’re hot
-they rise when we’re cold-this traps a layer of insulating air. Hair erector muscles contract

Question 6

why is water content controlled

Answer 6

to protect cells

Question 7

how does skin maintain water content

Answer 7

-sweat glands produce sweat
-water ions and urea are lost from the skin

Question 8

how do the lungs maintain water content

Answer 8

-water leave the body via lungs when exhaling

Question 9

how do kidneys maintain water content

Answer 9

-remove excess water salts and urea

Question 10

what happens if concentration of blood plasma is too dilute/concentrated

Answer 10

-dilute- kidneys excrete water in urine
-concentrated- kidneys excrete less water

Question 11

what does the amount of water excreted by kidneys depend on

Answer 11

-external temp
-exercise
-intake of fluids and salts

Question 12

what is urine

Answer 12

-clear, yellow liquid produced by kidneys
-contains excess water, urea and salts

Question 13

what are urobilins

Answer 13

found in urine
yellow pigments produced in liver from the breakdown of haemoglobin

Question 14

what is urea

Answer 14

produced in liver from breakdown of amino acids

Question 15

what does the volume of urine depend on

Answer 15

the amount of water taken in and water lost though sweating and breathing

Question 16

how is blood transported to kidneys

Answer 16

-through renal artery where it’s filtered at a high pressure

Question 17

what does the kidney do to the blood

Answer 17

-reabsorbs useful materials(glucose, salt ions, water)

Question 18

what happens to the blood after it has been to the kidneys

Answer 18

-it is purified, so it returns to circulatory system through renal vein

Question 19

what does the pituitary gland do

Answer 19

tells the body what to do
tells other glands to release hormones

Question 20

what does the amount of ADH released into bloodstream depend on

Answer 20

the water concentration in blood plasma

Question 21

what happens with ADH if there’s too much water in blood

Answer 21

-hypothalamus detects water level
-pituitary gland releases less ADH
-less water reabsorbed by kidneys
-blood water level returns to normal

Question 22

what happens with ADH if there’s not enough much water in blood

Answer 22

-hypothalamus detects water level
-pituitary gland releases ADH
-more reabsorbed by kidneys
-blood water level returns to normal

Question 23

what is a negative control system

Answer 23

it responds when conditions change from the ideal and returns conditions to the ideal
-it’s continuous