lecture 6

Question 1

what is the immune system?

Answer 1

it is the bodies defence system to distinguish and process foreign and self-threats

Question 2

the immune system responds to antigens. what are antigens? examples

Answer 2

antigens are any molecule that can stimulate an immune response i.e. microbes (bacteria, viruses), smoke, pollen, etc

Question 3

is exercise an antigen?

Answer 3

yes, because it produces some damage in the muscle and then you get an immune response.

not all immune responses are bad

Question 4

what are the three lines of defence in the immune system?

Answer 4

1st line - physical & (bio) chemical barriers - skin, earwax, stomach acid

2nd line - innate (non specific) immune response - quick response

3rd line - adaptive (specific) immune response - slower, memory for future responses
- T and B lymphocytes

Question 5

what lymphocytes are apart of the adaptive immune system

Answer 5

T and B lymphocyte cells

Question 6

when does the immune system develop?

Answer 6

the innate immune system is present in the body at week 4

functional T cells develop at week 16 of pregnancy

Question 7

what happens to the foetus immune system at birth?

Answer 7

the innate immune system is muted at birth otherwise it would recognise the maternal cells as antigens and then attack them.

Question 8

what happens in the childhood immunity?

Answer 8

• immune system matures
• maternal antibodies mirror the immunity of the mother
• continually make immune system stronger throughout growth (the more you are exposed)

Question 9

what happens with the immune system in the aged?

Answer 9

• immune system declines in the ages
• Lower number of naive T and B cells = decreased ability to respond to new diseases
• innate immune system show decrease phagocytic ability

Question 10

why is childhood immunity important?

Answer 10

important for early protection against infectious disease over the first 6 months of life

Question 11

when is the greatest risk of death from infection?

Answer 11

very early in life and later in life (newborn & elderly)

Question 12

what is the endocrine system?

Answer 12

it is the system that secretes hormones

Question 13

what are hormones ?

Answer 13

are the chemical messengers which are released into the body by your endocrine glands

Question 14

where do hormones go?

Answer 14

they either reach a target tissue directly or pass into cell to nucleus

Question 15

what are the two different types of hormones? examples also

Answer 15

Amino acid hormones - cannot cross membrane
eg. epinephrine, glucagon, thyroxine
lipid derived hormones - its a lipid soluble so can cross membrane
eg. steroid hormones, estrogen, testosterone

Question 16

what is the major endocrine gland?

Answer 16

the Hypothalamus

Question 17

what does the growth hormone do?

Answer 17

growth of connective tissue, bone growth and muscle hypertrophy

Question 18

what are the three actions of hormones?

Answer 18

1. morphogenesis - regulate physical growth and maturation of individuals
2. integration - integrate activities of the body in response to internal and external stimuli
3. Maintenance - act to maintain the internal environment of the body

Question 19

what does Morphogenesis do?

Answer 19

regulate physical growth and maturation of individuals

e.g. Growth hormone (GH)

Question 20

what happens when the Hypothalamus secretes GRGH (growth hormone releasing hormone)??

Answer 20

this stimulates GH release from pituitary gland, which stimulates liver to secrete insulin-like growth factor (IGF) hormones

Question 21

What is IGF-1 and what does it do

Answer 21

IGF-1 - a insulin like growth factor which is a potent stimulator of rapid production of cartilage cells at epiphyseal plate

Question 22

what hormones do we need for linear growth to occur in children?

Answer 22

IGF-1 (insulin like growth factor) , GH (growth hormone), TH (thyroid hormone)

Question 23

what does growth hormone do in adults?

Answer 23

• stimulates protein synthesis in muscle and the release of fatty acids from adipose tissue (anabolic effect)
• used in the synthesis of proteins

Question 24

when does growth hormone usually happen? what happens if you stay awake all night consistently?

Answer 24

growth hormone is usually secreted when asleep. therefore if always awake you may be stunted in growth

Question 25

what are the sex steroids which are most commonly studies in growing children

Answer 25

testosterone and estradiol

Question 26

what is the second hormonal action??

Answer 26

Integration - through circulation to most parts of the body, integrate activities of the body in response to internal and external stimuli e.g. adrenaline/epinephrine

Question 27

What is the third hormone action? examples

Answer 27

Maintenance - act to maintain the internal environment of the body (homeostasis) e.g. insulin, glucagon, ADH, Calcitonin aldosterone

Question 28

what does insulin do?

Answer 28

it is secreted by pancreas - it increases glucose uptake from blood and glycogen storage - necessary for full expression of GH effects

Question 29

what happens to the thyroid when ageing?

Answer 29

- thyroid often becomes lumpy (nodular). | - metabolic rate gradually declines, beginning at age 20

Question 30

why is normal thyroid function necessary?

Answer 30

- for normal physiological growth and maturation - GH can not produce its normal effects without thyroxine - thyroid hormones accelerate most processes

Question 31

what are the endocrine changes with ageing ??

Answer 31

the endocrine system shows relatively few functional changes with age. with the most dramatic exception is the decline in the concentration of reproductive hormones

Question 32

what is menopause? how does it occur due to ageing ^

Answer 32

menopause is when a womens ovaries stops releasing eggs. this is due to a decrease of the female hormones estrogen and progesterone = menstrual activity decreases and eventually ceases

Question 33

what are the changes in the male reproductive system due to ageing?

Answer 33

decrease sperm production | decrease erectile disfunction