response and regulation

Question 1

what is homeostasis

Answer 1

the maintenance of stable internal environment in the body despite fluctuations in internal and external conditions

Question 2

why is homeostasis important

Answer 2

to ensure optimum conditions for enzymes and cellular processes in the body

Question 3

what type of chemicals help to ensure optimum conditions within the body

Answer 3

hormones

Question 4

what is a hormone

Answer 4

a cell signalling molecule produced by the endocrine glands and released into the blood

travels to a target organ and binds, initiating a response

Question 5

what conditions in the body must be controlled by homeostasis

Answer 5

temperature
blood glucose concentration
water levels

Question 6

why must body temperature be controlled

Answer 6

enzymes work best at their optimum temperature

deviations from optimum temperature decrease the rate of enzyme-controlled reactions

Question 7

what is the optimum temperature for enzymes in the human body

Answer 7

37°C

Question 8

what responses occur when the body temperature rises above 37°C

Answer 8

vasodilation
sweating
erector muscles relax, hairs lie flat

Question 9

where is sweat produced

Answer 9

sweat glands

Question 10

how does sweating help reduce body temperature

Answer 10

heat energy is used to evaporate sweat. increased heat transfer from the skin to the environment decreases body temperature

Question 11

what is vasodilation

Answer 11

dilation of blood vessels near the skin surface
blood flows closer to the skins surface
greater heater loss to the surroundings

Question 12

outline the responses when the body temperature decreases below 37°C

Answer 12

vasoconstriction
shivering
hair erector muscles contract
little sweat is produced

Question 13

how does shivering help increase body temperature

Answer 13

involuntary contraction of muscles generates heat from respiration.

Question 14

how does the contraction of hair erector muscles help increase body temperature

Answer 14

hairs stand on end creating pockets of air between hairs and a layer of insulation

Question 15

what is vasoconstriction

Answer 15

constriction of blood vessels near skin surface
less blood flows close to skin surface
less heat loss to the surroundings

Question 16

why must blood glucose concentrations be controlled

Answer 16

if blood glucose concentration rise too high the body risks dehydration

if blood glucose become to low the rate of cellular respiration decreases

Question 17

which organ is responsible for the control of blood glucose concentrations

Answer 17

pancreas

Question 18

how is blood glucose concentration controlled

Answer 18

blood glucose is controlled by insulin ( a hormone) which is secreted by the blood

Question 19

what does insulin do to blood glucose levels

Answer 19

it causes them to decrease back to a normal level

glucose os converted into glycogen, a storage molecule

insulin causes liver and muscle cells to increase their uptake of glucose from the blood

Question 20

what does glucagon do to blood glucose levels

Answer 20

it causes them to rise back to normal
it causes a breakdown of glycogen to glucose in the liver
glucose is released into the blood

Question 21

what is the control of blood glucose concentration an example of

Answer 21

negative feedback

Question 22

what happens when blood glucose concentrations come to high

Answer 22

blood glucose concentration increases above a set point

pancreas secretes insulin and stops producing glucagon

liver cells convert glucose to glycogen which is stored

blood glucose concentration decreases, returning to normal level

Question 23

describe what happens when blood glucose levels become too low

Answer 23

blood glucose concentration decreases below a set point

pancreas secretes glucagon and stops producing insulin

liver cells convert glycogen into glucose which is released into blood

blood glucose concentration increases, returning to norma level

Question 24

what is diabetes

Answer 24

a condition where the homeostatic control of blood glucose levels stop working

Question 25

what are the two types of diabetes

Answer 25

type 1 diabetes

type 2 diabetes

Question 26

what causes type one diabetes

Answer 26

the immune system attacks and destroys insulin producing cells
therefore the pancreas does not produce enough insulin

Question 27

how is type one diabetes treated

Answer 27

daily insulin injections at meal times
managing diet (limit intake of refined sugars)
regularly testing blood glucose levels

Question 28

what is the cause of type 2 diabetes

Answer 28

person develops insulin resistance (often due to obesity)

Question 29

how is type 2 diabetes treated

Answer 29

managing diet (limit intake of sugars)
regular exercise
drugs e.g metformin

Question 30

what is a drug

Question 31

describe the effects of alcohol on the body

Answer 31

decreased reaction time
addictive
causes liver damage, cardiovascular disease

Question 32

what is negative feedback

Answer 32

negative feedback is a corrective mechanism that allows only small fluctuations around a set point.
e.g. the control of blood glucose concentration

Question 33

what is a sense organ

Answer 33

a group of receptor cels that detect specific stimuli and send information to the central nervous system along neurones.

Question 34

what is the process of the reflex arc

Answer 34

receptor cells pick up a harmful stimulus
stimulation of the. pain receptor
impulses travel along the sensory neurone
impulses are passed along a relay neurone via a synapse
impulses travel along a motor neurone via a synapse
when impulses reach the effector (muscle) the contract

Question 35

what are the characteristics of the reflex arc

Answer 35

rapid
automatic
protective