Topic 7 - Animal Coordination, Control and Homeostatis Flashcards
name some endocrine glands
pituitary, thyroid, andrenals, ovaries, testies, pancreas
pituitary gland -> what does it release (menstrual cycle)
‘master gland’ secrete several hormones into the blood in response to body conditions
-> releases FSH and LH
where is the pituitary gland
at the base of the brain
what does the adrenal gland produce
adrenaline
what do testes produce
testosterone
why does thyroid gland produce
thyroxine
what does pancreas produce
insulin and glucagon
what do ovaries produce
oestrogen and progesterone
target organ
organ that is affected by specific hormone
homeostasis
Regulation of the internal condition of an organism - to maintain optimum conditions in response to internal and external changes
What two automatic control systems detect changes and respond to them?
nervous system and endocrine system
endocrine system
Composed of glands which secrete chemicals called hormones directly into the bloodstream
oestrogen function
Stop FSH and releases LH and prepare the lining of the womb for pregnancy
progesterone function
- Inhibits the production of FSH and LH to maintain the uterus lining
- if the egg is not fertilised progesterone levels decrease which causes menstruation (the breaking down of the uterus lining)
FSH (follicle stimulating hormone) function
Causes the eggs in the ovaries to mature
LH (luteinising hormone) function
Stimulates the release of the egg at ovulation
testosterone function
Stimulates sperm production
thyroxine function
- causes heart cells to contract more rapidly and strongly (more respiration)
- increases the rate of which proteins and carbohydrates are broken down inside cells - stimulates the basal metabolic rate (BMR); this is the speed at which chemical reactions occur in the body when it’s at rest
Adrenaline function - what does it do to the body
causes changes in your body that help you to act in a sudden stressful situation:
- increases blood glucose concentration for increased respiration of muscle cells
- increasing heart rate and breathing rate so glucose and oxygen can be delivered to muscle cells and carbon dioxide taken away from muscle cells more quickly
- increase blood pressure
- dilating pupils to allow as much light as possible to reach the retina so more information can be sent to the brain
- diverting blood flow towards muscles and away from non-essential parts of the body to ensure the reactants of respiration are as available as possible
metabolic rate
Rate at which the energy stored in your food is transferred by all the reactions that take place in your body to keep you alive
What is the hormone that affects metabolic rate?
Thyroxine
How do you measure the resting metabolic rate
When the body is at rest in a warm room and long after the person last had a meal
What are the two hormones that control the amount of thyroxine produced by the thyroid gland and where are these hormones released from?
TRH (thyrotropin releasing hormone) is released in the hypothalamus
TSH (thyroid stimulating hormone) is released in the pituitary gland
metabolism
processes in the body that keep us alive
-> e.g. contraction of heart muscle, breathing, Cell division, growth and differentiation
What happens if too much thyroxine is produced?
- it has a greater inhibiting effect on the hypothalamus that less TRH is released
- less TRH means that the pituitary is stimulated less so that less TSH is released which reduces a stimulus on the thyroid gland so that less thyroxine is released
What happens if two little thyroxine is released?
Low blood concentration of thyroxine stimulates the hypothalamus to release more TRH which stimulates the pituitary to release more TSH which stimulates the thyroid to release more thyroxine
Why is the blood concentration of thyroxine negative feedback?
A there is an increase in thyroxine concentration directly causes change that brings about a decrease in the amount of thyroxine released into the blood
HYPERthyroidism
Caused by an overactive thyroid gland, secreting too much thyroxine into the bloodstream which causes an increase in BMR
HYPOthyroidism
Caused by an underactive thyroid gland creating two little thyroxine into the bloodstream which can lead heart and nerve problems and death
How does more adrenaline get released in frightening or exciting situations?
An increase in impulses from neurons reaching the adrenal glands from the spinal cord trigger the release of large amounts of adrenaline into the blood
What is the effect of adrenaline on the heart?
Heart muscles cells contract more rapidly which increases the heart rate and more strongly which increases the blood pressure
What is the effect of adrenaline on blood vessels (wide and narrow)?
- when the diameter of the blood vessels which lead to the muscles widen it increases blood flow to the muscles
- when the diameter of the blood vessels that lead to other organs narrow, it reduces blood flow to those organs and increases blood flow to the muscles that need it
What is the effect of adrenaline on the liver?
Liver cells change glycogen to glucose and release it into the blood which increases blood sugar concentration
Why does adrenaline breakdown glycogen?
When glycogen is broken down, the glucose can be released into the body providing cells with glucose for respiration
Menstrual cycle
Cycle of changes in a woman’s reproductive system that takes about 28 days
What is the point of the menstrual cycle?
To prepare the woman’s body for the fertilisation of an egg cell leading to pregnancy.
What happens during menstruation? (Day 1-5)
When the thickened part of the uterus lining breaks down and is lost with the unfertilised egg during a bleed or period
What happens when menstruation ends? (Day 11-13)
The uterus lining starts to thicken again and ovulation takes place
What happens during ovulation? (Day 14-20)
An egg cell is released from an ovary
What happens after ovulation? (Day 21-28)
The lining is maintained ready to accept a fertilise eggs
What are the female reproductive hormones
Oestrogen and progesterone
What are the male reproductive hormones?
Testosterone
Secondary sex characteristics
Any physical characteristics developing at puberty which distinguishes between the sexes but is not directly involved in reproduction
What are female secondary sex characteristics
- growth spurt
- Underarm hair and pubic hair
- breast development
- Hips widen
- Mature egg start to form every month in the ovaries
- Growth of the uterus
What are some male secondary sex characteristics?
- growth spurts
- Underarm hair, facial hair and pubic hair
- Larynx gets bigger and the voice breaks
- shoulders and chest broaden
- Testes grow and start producing sperm
What are the four hormones that control the menstrual cycle?
- FSH
- LH
- Progesterone
- Oestrogen
Contraception
Prevention of fertilisation
What some examples of contraception and how it prevents fertilisation
- male condom - placed over erect penis, prevents sperm entering the vagina
- hormone pill or implant - releases hormones to prevent ovulation and thickens mucus at the cervix, making it difficult for sperm cells to pass through
What controls the release of FSH and LH?
Controlled by the concentration of oestrogen and progesterone
Describe the menstrual cycle using the hormones
- FSH is released by the pituitary gland and stimulates the development of a follicle in the ovary
- An egg matures inside the follicle and the follicle produces oestrogen
- oestrogen causes the lining of the uterus to build up
- When oestrogen reaches a peak level, it stimulates the release of LH from the charity gun -> this causes ovulation
- The follicle becomes a corpus luteum and starts producing progesterone -> inhibits release of LH and FSH
- Progesterone maintains the lining of the uterus to prepare for pregnancy
- if the egg is not fertilised, the corpus luteum breaks down and progesterone levels decrease -> this causes menstruation
- this repeats
What causes infertility?
- lack of regular ovulation
- Insufficient levels of testosterone, affecting the development of sperm
- blocked or damaged fallopian tubes
What are the risk factors for infertility?
- age - the older the person is, the less likely they are to conceive
- being overweight or obese
- Sexually transmitted infections (STIS)
- smoking snd alcohol - affects the quality of the sperm
- environmental factors - exposure to certain pesticides and chemicals
- stress
How is IVF carried out?
- egg follicle maturation stimulated by hormones (FSH and LH) that are injected into the women
- egg cells released by many follicles and taken from ovaries
- Sperm cells taken from man
- eggs and sperm combine to allow fertilisation
- one or two healthy embryos placed in uterus
when is IVF used
If the oviducts have been damaged or blocked by infection
Clomifene therapy
If a woman has naturally low levels of FSH and LH, she can undergo clomifene therapy -> it’s a drug which stimulates the release of FSH and LH
How do you find out if you’re pregnant
pee on a pregnancy test
How do you get glucose from in the body?
During the digestion of carbohydrates
Why is glucose need in your body and how does it get there?
Glucose is easily absorbed from the small intestine into the blood and then into cells where it is broken down during respiration
Why is it bad if there is a high concentration of glucose in the blood
it can damage organs
What happens when your glucose levels get too high
- this stimulates certain cells in the pancreas to release the hormone insulin
- insulin cause the cells in the liver and other organs to take in glucose which causes a fall in blood glucose concentration
What happens when blood glucose levels get too low
- The insulin releasing cells in the pancreas release less and less insulin
- pancreas releases glucagon which stimulates liver and muscle cells to convert stored glycogen back into glucose to be released into the blood stream
What happens when glucose is absorbed by the liver?
Glucose is converted into glycogen for storage in the liver cells
homeostasis
Maintaining constant conditions inside the body
Type 1 diabetes
Pancreas cannot secrete insulin, so it means that they cannot control rising blood glucose concentration -> this happens because the cells have been destroyed by the bodies immune system
How do you test for type 1 diabetes
When blood glucose concentration is too high, glucose can be detected in the urine
Can type 1 diabetes be cured?
No but you can inject insulin into the fat layer below the skin where it can enter the blood causing blood glucose concentration to fall
How do you get type 1 diabetes
It is inherited
Type 2 diabetes
Insulin releasing cells do not produce enough insulin OR target organs do not respond properly to the hormone
Can type 2 diabetes be cured - how to fix it?
No but it can be managed/reversed - you can eat more healthy, keep the amount of sugar in the diet low, be physically active cause it takes glucose out of the blood, or give medicine to reduce the amount of glucose that the liver releases into the blood or increase the sensitivity of the cells and the target organs that respond to insulin, this will help
What can make you more likely to develop type 2 diabetes
- more body fat
- being older
BMI equation
mass (kg)
height2 (m)
waist:hip ratio equation
Waist measurement divided by hip measurement
thermoregulation
Is the control of body temperature which keeps the temperature of the major organs closer to 37°C most of the time
what constantly monitors your body temp
your hypothalamus -> it receives information from the temperature receptors in the dermis of the skin
What happens if the hypothalamus detects blood or brain temperatures starting to fall BELOW 37°C or it detects a cold environment?
- shivers which is when muscle starts contracting relax rapidly -> this energy released from cell respiration from shivering warms you up
- contraction of erector muscles in the dermis of the skin causes body has to stand up right - this traps a layer of insulation so less energy is lost
- Reduction of blood flow near to the skin keeps warm blood deeper inside the body -> this reduces the rate of transfer of energy to the air by heating
What happens if the hypothalamus detects blood or brain temperature starting to rise ABOVE 37°C??
- you sweat -> sweat spreads out as a thin layer over the skin epidermis where it evaporates; as sweat evaporates it transfers energy from the skin to the surroundings by heating so the skin cools down
- Increases blood flow nearer to the surface to the skin -> this makes it easier for the blood to transfer energy to the air so we cool down
- your hair lies flat as erector muscle is relaxed
vasoconstriction
Narrowing of blood vessels
How does vasoconstriction cause your body to heat up when it’s too cold?
- your hypothalamus sends nerve impulses to small arteries deep in the skin causing them to narrow
- This reduces blood flowing in capillaries near the surface of the skin and helps to reduce energy transferred to the surroundings
Vasodilation
When the arteries widen
How does vasodilation help cool the body down when it is too hot?
- The hypothalamus causes the small arteries to widen (vasodilation)
- This increases blood flow through capillaries, bringing warm blood near to the skin and increasing energy transferred to the surroundings
osmoregularion
Control of the balance of water and mineral salts in the body
Why is it bad if the body has too much water?
Cells may taken or lose too much water by osmosis:
- too much - this can damage cells because water and cells allows all the molecules in the cell reactions to move around
- not enough - water is needed to maintain the shape of the cell
function of urinary system
- To remove excess amounts of some substances from the blood, including water and mineral salts
- To remove waste products such as urea
how is urea produced
Produced in liver cells from the breakdown of amino acids that are in greater amount than are needed
How does the urinary system produce urine to come out of your private parts?
- The renal arteries carry blood from the body to the kidneys
- The kidneys remove unwanted substances from the blood and make urine
- The ureter carries urine from the kidney to the bladder
- The bladder stores urine
- A muscle keeps the exit from the bladder closed into aperson decides to urinate
- urine flows through the urethra to the outside of the body
After the kidneys remove waste substances from the blood where does the blood go?
The renal veins carry blood with waste removed back to the body
what are the treatments for kidney failure?
- kidney dialysis
- organ donation
How does kidney dialysis work?
- blood carrying waste passes to the machine from a vein
- Dialysis fluid contains the same concentration of glucose is blood plasma so that glucose is not diffused out of the blood
- There is diffusion of urea and other substances out of the blood and into the dialysis fluid -> there is a thin partially permeable membrane separating blood from dialysis fluid making diffusion easier
Kidney dialysis
A procedure that removes excess fluid and waste products from the blood when the kidneys are no longer functioning properly
Organ donation - kidney
A kidney from another person is putting into a patient’s body and attached to their blood system
How does an organ donation not work to replace a kidney and how can this be fixed
Kidney cells have antigens on them and cells in the immune system recognise an attack strange antigens which can cause rejection of the donated kidney; this is why the antigens on the donated organ must therefore be matched to those on the patients cell (this can take a long time)
-> even with a good match, the patient will need long life medication to prevent the kidney being rejected - this medication affects the bodies response to infection so the patient may catch infections more easily
How is urine made in the nephron?
- blood from renal artery flows through a network of capillaries called a glomerulus, which runs inside the Bowman’s capsule
- The Bowman’s capsule and glomerulus are adapted to let very small molecules such as water glucose through into the nephron; large molecule such as proteins and blood cells stay in the blood. This process is called filtration.
- The filtration fluid flows through the first convoluted tube; selective reabsorption of useful substances that the body needs occurs here (this includes glucose and some minerals) by active transport
- water and mineral ions are reabsorbed by osmosis in the loop of Henle and the collecting duct
- finally this flows through secondary convoluted tubule
- this carries on flowing into the collective duct where water can be reabsorbed into the blood due to the amount of water already in the blood and at the end of the nephron the remaining fluid is urine
- At the end of the nephron, the remaining fluid flows into the ureter -> the fluid contains excess water that the body does not need plus urea and other waste substances
Nephron
A filtering unit in the kidney that removes waste from the blood and produces urine
How is the nephron adapted for absorption of substances?
- there is a large surface area of contact between the nephron and capillaries
- The cell membrane of the cell line in the first complicated tube has tiny folds called microvilli. These increase the surface area: volume ratio of the cells.
- Cells that have protein pumps in their cell membrane contain many mitochondria
What happens when the hypothalamus detects there’s two little water in the blood?
It releases ADH from the pituitary gland which increases the permeability of the collecting duct in nephrons and increases the concentration of the urine
ADH (antidiuretic hormone)
Hormone that helps the body regulate water and urine production by increasing the permeability of water in the collecting duct
-> highly permeable means more water is reabsorbed making the urine very concentrated
What happens if there’s too much water in the blood?
The hypothalamus causes less ADH to be released from the pituitary gland making the collection duct less permeable so there is less reabsorption of water into the blood which produces a more dilute urine
How can oestrogen act as a contraceptive
Inhibits FSH production so that eggs can’t mature
how can progesterone act as a contraceptive
Stimulate the production of mucus in the cervix so sperm can’t enter the uterus
what hormones does ‘the pill’ contain
Oestrogen and progesterone
In IVF why are embryos kept in an incubator whilst in the lab
To provide optimum temperature for enzymes and thus cell growth
Deamination
Excess amino acids need to be excreted safely - the liver removes the amino part of the amino acids and turns them into lipids or carbohydrates
