Topic 7: Coordination & Control Flashcards
What are endocrine glands?
Glands that secrete chemical messengers (hormones) directly into the bloodstream which carries them to the target organ
What are all of the glands in the endocrine system?
- Pituitary gland
- Thyroid gland
- Adrenal gland
- Pancreas
- Ovaries
- Testes
PeeTeaAPOT
What gland is adrenaline released from?
Adrenal gland
What are the 2 main effects of adrenaline on the body?
- Liver converts glycogen into glucose - increases blood glucose levels - more glucose is transported to cells for respiration
- Heart contracts more frequently with force - higher heart rate and blood pressure - increases blood flow to muscles so more oxygen is produced
What does adrenaline prepare your body for?
A fight or flight response
What does thyroxine do?
Regulates metabolic rate
What gland produces thyroxine?
Thyroid gland
What is metabolic rate?
The rate at which energy stored in food is transferred by all the reactions in your body to keep you alive
What happens when the body detects blood thyroxine levels are too low?
- The hypothalamus release TRH
- TRH stimulates pituitary gland to secrete TSH
- TSH stimulates the thyroid gland to secrete thyroxine
- Thyroxine levels return to normal
What happens when the body detects blood thyroxine levels are too high?
- The secretion of TRH and TSH are inhibited
- Thyroxine levels return to normal
What type of feedback are thyroxine levels controlled by?
Negative feedback
How to remember what hormones are involved in the menstrual cycle and what gland they’re secreted from?
FSH Pituitary
Oestrogen Ovaries
LH Pituitary
Progesterone Ovaries
FOLP POPO
What happens on day 1 of the menstrual cycle?
Uterus lining begins to break down and menstruation starts
(FSH levels cause an egg to mature in an ovary)
What happens on day 4 of the menstrual cycle?
Uterus lining is prepared - builds up into a thick spongy layer full of blood vessels ready to receive a fertilised egg
(Oestrogen causes the uterus lining to thicken)
What happens on day 14 of the menstrual cycle?
Ovulation - the egg develops and is released from the ovary
(LH stimulates the release of the egg or ovulation)
What happens on day 28 of the menstrual cycle?
Lining of the uterus is maintained BUT if no fertilised egg lands on the wall, the lining breaks down again and the cycle starts again
(Progesterone maintains uterus lining)
What is the role of FSH?
Matures the egg
What is the role of oestrogen?
Thicken the uterus lining
What is the role of LH?
Causes the egg to be released
What is the role of progesterone?
Maintains the uterus lining
What is the hormone feedback in the menstrual cycle if someone isnt pregnant?
- FSH stimulates the release of oestrogen
- Oestrogen stimulates the release of LH
- LH will stimulate the development of the corpus luteum
- The corpus luteum will release progesterone
What is the hormone feedback in the menstrual cycle if someone is pregnant?
- Oestrogen will inhibit the release of FSH
- Progesterone will inhibit the release of LH and FSH
- Levels of progesterone will stay high during pregnancy
What does ART stand for?
Assisted Reproductive Technology
What does IVF stand for?
In Vitro Fertilisation
What are examples of ART?
IVF
Clomifene therapy
What is IVF?
When eggs are handled and fertilised outside of the body
What is the process of IVF?
- The woman is given FSH and LH to stimulate egg production
- The eggs are then collected from the woman’s ovaries
- The eggs are then fertilised in a lab using the man’s sperm
- The fertilised eggs are grown into embryos
- Once the embryos are tiny balls of cells, one or two of them are transferred to the woman’s uterus
Advantages of IVF?
Gives a woman a natural birth
Allows infertile couples to have a child
Disadvantages of IVF?
Expensive
There a limited number of times you can have them for free
Risk of having multiple births e.g. octomum
What is the process of clomifene therapy?
- A woman who doesn’t ovulate or doesn’t ovulate regularly may take clomifene
- More FSH and LH are released
- Egg maturation and ovulation is stimulated
- Woman can have intercourse when she knows she’s ovulating
- Increased chance of pregnancy
What is contraception?
Methods of reducing the likelihood of sperm reaching an ovulated egg
What are the 2 types of contraception?
- Hormonal
- Barrier
Examples of hormonal methods of contraception?
Pill
Injection
Patch
Advantages of hormonal methods of contraception?
When used correctly, more effective than barrier methods
Can reduce risks of cancer
Disadvantages of hormonal methods of contraception?
There are side effects - changes in weight, mood swings, high blood pressure etc.
Don’t protect against STIs
Examples of barrier methods of contraception?
Condom - have spermicidal agents on them, kill sperm
Diaphragm
Sterilisation
IUDs
Advantages of barrier methods of contraception?
Fewer side effects than hormonal methods
They protect against STIs - prevent sperm and egg meeting
IUDs last long - 10 years
Disadvantages of barrier methods of contraception?
Condoms can tear or rip
Sterilisation is irreversible
IUDs can cause an ectopic pregnancy
What hormones does the pill contain? Why
Oestrogen - inhibits FSH production - preventing release of egg
Progesterone - stimulates production of thick cervical mucus - prevents sperm entry
What is homeostasis?
The regulation of the conditions inside your body and cells, it maintains a stable internal environment in response to changes in internal and external conditions
Why is homeostasis important?
To maintain constant conditions for cells to function properly
What happens in our body when glucose levels are too high?
- Blood has too much glucose
- Pancreas detects high glucose levels and secretes insulin
- Insulin causes glucose to move into cells
- Insulin makes the liver turn glucose into glycogen - which is stored in the liver and muscles
- Blood glucose is reduced
What happens in the body when glucose levels are too low?
- Blood has too little glucose
- Pancreas detects low glucose levels and secretes glucagon
- Glucagon makes the liver turn glycogen into glucose - which is released from the liver
- Blood glucose is increased
What type of feedback cycle do insulin and glucagon work in?
Negative feedback
What causes type 1 diabetes?
When the pancreas produces little to no insulin
What is the cause of type 2 diabetes?
The cells no longer responding to insulin properly
What is the effect of type 1 diabetes?
Blood glucose can rise to dangerously high levels
What is the effect of type 2 diabetes?
Blood glucose can rise to dangerously high levels
What is the treatment for type 1 diabetes?
Insulin therapy e.g. injections
What is the treatment for type 2 diabetes?
Healthy diet and regular exercise
What can obesity lead to?
An increased risk of type 2 diabetes
What are the 2 ways to measure obesity?
- BMI
- Waist to hip ratio
How to calculate BMI?
BMI = mass/height^2
How to calculate waist to hip ratio?
Waist to hip ratio = waist circumference/hip circumference
What BMI does someone have to have to be considered obese?
A BMI of over 30
What waist to hip ratio does a man have to have to have an increased risk of type 2 diabetes?
Above 1.0
What waist to hip ratio does a woman have to have to have an increased risk of type 2 diabetes?
Over 0.85
What are the 3 parts within homeostasis?
- Controlling blood glucose levels
- Thermoregulation
- Osmoregulation
What does thermoregulation do?
Keeps the body at the optimum temperature for enzyme activity
Where are temperature receptors located in the body?
- In the thermoregulatory centre in the hypothalamus (brain)
- In the skin - the epidermis (outer layer) and dermis (deeper layer)
What happens when the body gets too cold?
- Temperature receptors detect core body temperature is too low
- Thermoregulatory centre receives information - triggers effectors
- Effectors produce a response to counteract that change
- Body warms up
What happens when the body gets too hot?
- Temperature receptors detect core body temperature is too high
- Thermoregulatory centre receives information - triggers effectors
- Effectors produce a response to counteract that change
- Body cools down
When you’re hot, what do the effector cells try to do?
Transfer energy from the skin to the environment
How do effectors transfer energy to surroundings to cool down the body?
Hair erector muscles relax - hairs lie flat
Sweet glands released sweat through pores in the epidermis - evaporation of water in sweat causes cooling
Blood vessels go through VASODILATION - they dilate so more blood flows close to surface of skin
When you’re cold, what do the effector cells try to do?
Reduce the energy transferred to surroundings
How do effectors reduce the transfer of energy to surroundings to heat up the body?
Erected hairs trap an insulating layer of air
No sweat is released through pores in the epidermis
Shivering occurs - muscles contract rapidly to increase respiration rate
Blood vessels go through VASOCONSTRICTION - they constrict so less blood flows close to surface of skin
What do temperature receptors do?
Detect changes in temperature and inform the hypothalamus by nervous impulses (if the receptor cells in the skin detect it)
What does the hypothalamus do in thermoregulation?
Responds to information (that have been sent to it by receptors) by sending nerve impulses to effectors in the skin to maintain body temperature
What is osmoregulation?
The maintaining of the body’s water content at the right level for cells to function
What happens when water levels are too high?
Water moves into cells and they burst
What happens when water content is too low?
Water moves out of cells and they shrink
What is the structure of the urinary system? With functions?
- Renal artery and renal vein (artery takes oxygenated blood into the kidneys from the heart & veins takes deoxygenated blood away from kidneys and to heart)
- Kidneys - removes substances from the blood and produce urine
- Ureter - carries urine to bladder
- Bladder - stores urine
- Urthera - urine leaves body through this
What are the 3 roles of the kidney?
- Removal of urea from blood
- Adjustment of ion levels in blood
- Adjustment of water content in blood
Where is urea produced?
In the liver from the breakdown of excess amino acids
What is the structure of the nephron? With functions?
- Glomerulus - has small holes to allow small molecules to pass into nephron
- Bowman’s capsule - filtration occurs
- Proximal convoluted tubule - ions, glucose and amino acids are selectively reabsorbed by active transport
- Loop of henle - water reabsorption occurs
- Distal convoluted tubule
- Collecting duct - water reabsorption occurs due to ADH
What is the process of what happens to the blood when it enters the nephron?
- Blood enters from the renal artery
- Filtration occurs - liquid parts of the blood (water, urea, ions, glucose) are forced out
- Selective reabsorption occurs - all the glucose reabsorbed (against the concentration gradient) and reabsorption of sufficient ions and water
- Release of waste - urine released from nephron
What is the hormone involved in osmoregulation?
ADH
What does ADH do?
It makes the collecting ducts of the nephrons more permeable
What happens in the body when the bloods water content is too high?
- Hypothalamus detects that the bloods water content is too high
- The pituitary gland releases LESS ADH
- The collecting duct is therefore less permeable SO less water is reabsorbed from nephron
- Larger volume but a smaller concentration of urine is produced as more water is transported to the bladder and excreted in the urine since less is reabsorbed
- Water content decreases
What happens in the body when the bloods water content is too low?
- Brain detects that the bloods water content is too low
- The pituitary gland releases MORE ADH
- The collecting duct is therefore more permeable SO more water is reabsorbed from nephron
- Small volume but a high concentration of urine is produced as more water is absorbed by osmosis back into the blood since the levels were too low
- Water content increases W
What gland secretes ADH?
Pituitary gland
What does urine contain?
Water, urea and salts
What is the signs that someone’s kidney isn’t working properly? Why?
There being proteins in their wee - proteins in the blood are too large to pass through into the nephron SO it suggests the kidney isn’t working properly
What isn’t filtered in the bowman’s capsule? Why?
Red blood cells - too big
Proteins - too big
Why does a diabetic often have glucose in their urine?
Without insulin, blood glucose levels become too high, and kidneys can’t filter and reabsorb it - body gets rid of the excess through urine
How is the liver involved in the urinary system?
It breaks down amino acids into urea
What are the 2 ways to treat kidney failure?
- Kidney dialysis
- Kidney transplant
What is the process of dialysis?
- Blood is removed from the person and flows into the dialyzer where it’s kept separated from dialysis fluid by a partially permeable membrane
- The waste products diffuse out of the blood into the dialysis fluid which his then disposed of
- The clean blood returns to the patient
What actually is the dialysis fluid?
Ideal blood - it has the same concentration of dissolved ions and glucose as healthy blood
Why do waste products move from the blood into the dialysis fluid?
There is a concentration gradient for the movement of waste substances from the blood to the dialysis fluid - all of the waste diffuses from the blood in to the dialysis fluid from the high concentration in the blood to the lower concentration in the dialysis fluid
Via what process will the waste products move across the partially permeable membrane?
Diffusion
Advantages of dialysis?
Available to all kidney patients
No need for immunosuppressants
Disadvantages of kidney dialysis?
Patient must limit salt and protein intake between dialysis sessions
Expensive for the NHS
Regular dialysis sessions for 4-6 hours two or three times a week so it has an impact on the patients lifestyle
Advantages of kidney transplants?
Cheaper for NHS
Patients can lead a more normal life without having to watch what they eat or drink
Disadvantages of kidney transplants?
Shortage of kidney donors
There is risk of the immune system having a negative response to the new antigens
Only lasts 8-9 years on average
Must take immune suppressant drugs which increases risk of infection
What are the 3 steps of kidney transplants?
- Tissues must be matched - antigens on the kidney cells have to be matched as closely as possible
- Immunosuppressant drugs - less likely to reject a kidney BUT increases risk of disease
- Surgery - the new kidneys are inserted into the body
