M5-commincation and homeostasis

Question 1

define homeostasis

Answer 1

its the maintenance of a constant internal environment

Question 2

define positive feedback

Answer 2

positive feedback mechanisms amplify a change from the normal level, used to rapidly activate something

Question 3

why is positive feedback not involved in homeostasis?

Answer 3

it does not keep your internal environment constant

Question 4

what is a stimulus?

Answer 4

a change in the internal or external environment

Question 5

what is a receptor?

Answer 5

they detect a stimuli and a re specific

Question 6

what are effectors?

Answer 6

are cells that bring about a response to a stimulus to produce an effect

Question 7

what does a sensory neurone do?

Answer 7

transmit nerve impulses from receptors to the CNS

Question 8

what does a motor neurone do?

Answer 8

transmit nerve impulses from the CNS to effectors

Question 9

what does a relay neurone do?

Answer 9

transmit impulses between sensory neurones and motor neurone

Question 10

what is the CNS process?

Answer 10

stimulus - you see a friend waving

receptor - light receptors (photoreceptors) in you eyes detect the wave

CNS - CNS processes information and decides what to do about it

effectors - muscle cells are stimulated by the motor neurones

response - muscles contract to make your arm wave

Question 11

what do sensory receptors convert stimulus energy to?

Answer 11

nerve impulses

Question 12

where do axons carry nerve impulses?

Answer 12

Away from the cell body

Question 13

where do dendrites and dendrons carry nerve impulses?

Answer 13

towards the cell body

Question 14

what is the structure of sensory neurones?

Answer 14

short dendrites and one long dendron (receptor cells to cell body)

one long axon cell body to CNS)

Question 15

what is the structure of a motor neurone?

Answer 15

many short dendrites (CNS to cell body)

one long axon (cell body to effector cells)

Question 16

what is the structure of a relay neurone?

Answer 16

many short dendrites (sensory to cell body)

one axon (cell body to motor)

Question 17

what does a bigger stimulus cause?

Answer 17

it causes more frequent impulses

Question 18

what are the synapses called that use acetylcholine?

Answer 18

cholinergic synapses

Question 19

what is acetylcholine broken down by?

Answer 19

an enzyme called acetylcholinesterase

Question 20

what happens at the excitatory synapse?

Answer 20

neurotransmitters depolarise the postsynaptic membrane, making it fire an action potential if the threshold is reached

Question 21

what happens at the inhibitory synapse?

Answer 21

when neurotransmitters bind to receptors on the postsynaptic membrane, they hyperpolarise the membrane (making the potential difference more negative), preventing an action potential from being fired

Question 22

what is synaptic divergence?

Answer 22

when one neurone connects to many neurones and information can be dispersed to different parts of the body

Question 23

what is synaptic convergence?

Answer 23

when many neurones connect to one neurone and information can be amplified

Question 24

why does summation occur?

Answer 24

some stimulus are weak so little neurotransmitter is released into synaptic cleft meaning its not enough to excite the postsynaptic membrane to the threshold level and thus stimulate an action potential so summation can combine the effect of neurotransmitters

Question 25

what is spatial summation?

Answer 25

when neurones converge

Question 26

what is temporal summation?

Answer 26

is where 2 or more nerve impulses arrive in quick succession from the same presynaptic neurone

Question 27

what does the hormonal system send information as?

Answer 27

chemical signals

Question 28

what are hormones?

Answer 28

chemical messengers

Question 29

why is hormone a first messenger?

Answer 29

because it carries the chemical message from the endocrine gland to the receptor

Question 30

why are signalling molecules the second messengers?

Answer 30

they carry the chemical message frim the receptor to other parts of the cell they activate a cascade inside the cell

Question 31

what type of hormones does cortex secrete?

Answer 31

steroid hormones

Question 32

what are 2 examples of steroid hormones?

Answer 32

cortisol and aldosterone

Question 33

what type of hormone does medulla secret?

Answer 33

catecholamine hormones

Question 34

what are 2 examples of catecholamine hormones?

Answer 34

adrenaline and noraadrenaline

Question 35

what is the effect of catecholamine hormones?

Answer 35

increase heart and breathing rate break down of glycogen to glucose constriction of blood vessels

Question 36

what is the effect of steroid hormones?

Answer 36

supress the immune system increase blood volume and pressure by increasing uptake of sodium ions and water by kidneys stimulating the break down of proteins and fats, increasing energy available for brain and muscles to respond to the situation

Question 37

what is the endocrine tissue in the pancreas called?

Answer 37

islet of Langerhans

Question 38

what do the alpha cells secrete?

Answer 38

a hormone called glucagon

Question 39

what do the beta cells secrete?

Answer 39

a hormone called insulin

Question 40

under a light microscope, what colour do the alpha cells appear as?

Answer 40

pink

Question 41

under a light microscope, what colour do the beta cells appear as?

Answer 41

purple

Question 42

what is the stain used to differentiate beta and alpha cells?

Answer 42

chrome haematoxylin and phloxine

Question 43

what are ectotherms?

Answer 43

they cant control their body temperature internally they control their temperature by changing their behaviour

Question 44

what are 2 examples of ectotherms?

Answer 44

reptiles and fish

Question 45

what are endotherms?

Answer 45

they control their body temperature internally by homeostasis and they can also control their temperature by behaviour

Question 46

what are 2 mechanism that mammals do to reduce body temperature?

Answer 46

sweating - more sweat generated by sweat glands, water in sweat evaporates from surface of skin so skin is cooled vasodilation - arterioles near the surface of the skin dilate, more blood flows through capillaries in the surface layers of the dermis. more heat is lost from skin by radiation and temp is lowered

Question 47

what are 2 mechanism that mammals do to increase body temperature?

Answer 47

vasoconstriction - arterioles near the surface of the skin constrict so less blood flows through capillaries reducing heat loss hairs stand up - erector pili muscles contract which makes the hair stand up trapping more air and preventing heat loss

Question 48

what does the hypothalamus do?

Answer 48

control body temperature

Question 49

what type of food increases blood glucose concentration?

Answer 49

carbohydrates

Question 50

what does insulin do?

Answer 50

reduce blood glucose concentration when its too high

Question 51

what is the process activated by insulin?

Answer 51

glycogenesis glucose - glycogen

Question 52

what does glucagon do?

Answer 52

raises blood glucose concentration when its too low

Question 53

what is the process that is activated by glucagon?

Answer 53

glycogenolysis glycogen -- glucose gluconeogenesis glycerol/amino acids to glucose

Question 54

what is an example of negative feedback?

Answer 54

control of blood glucose control of body temperature

Question 55

what is an example of positive feedback

Answer 55

depolarisation

Question 56

what is type 1 diabetes?

Answer 56

it is an autoimmune disease, where no insulin is produced. in children/ young adults

Question 57

what are the treatments for type 1 diabetes?

Answer 57

insulin therapy - regular insulin injections diet and activity

Question 58

what is type 2 diabetes?

Answer 58

when beta cells dont product enough insulin or when the body cells dont respond properly to insulin linked with obesity

Question 59

what are the treatments for type 2 diabetes?

Answer 59

lifestyle changes so exercise, diet, medication - metformin ( acts on liver cells to reduce amount of glucose that they release into the blood)

Question 60

how can stem cells be used to cure diabetes?

Answer 60

they can be grown into beta cells beta cells will then be implanted into pancreas of a person with type 1 diabetes person would be able to make insulin as normal

Question 61

what are the pros for using genetically modified bacteria to make insulin?

Answer 61

cheaper than animal pancreases larger quantities produced religious and ethical reasons - pigs and animals