(P2) CB7: Animal Coordination, Control, & Homeostasis Flashcards
What is homeostasis
Keeping things in the body in balance
What must be controlled in the body (6 things)
Removal of CO2 (waste)
Removal of urea (waste)
Water content
Sugar content
Temperature
Ion content
What are ways in which heat is gained (3 things)
General metabolism
Muscle contraction
Radiation and conduction from the environment
What are ways in which heat is lost (3 things)
Expiration (breathing out) and excretion (pooing and weeing lol!!)
Evaporation of sweat
Radiation, conduction, and convection to the environment
What is the response if the body is too cold (4 things)
Shivering- releases heat from respiration
Subcutaneous fat (fat in the skin)- insulates
Hairs stand up- traps an insulators layer of air around the body
Vasoconstriction (blood vessels get thinner)- reduces blood flow near the skin surface
What is the response if the body is too hot (2 things)
Sweating- evaporation of sweat on the skin surface takes heat away from the blood, causing it to cool
Vasodilation (blood vessels widen)- increases blood flow near to the skin surface
Define negative feedback
A process that acts to reduce the changes of the process itself and restores systems to their original level
Define positive feedback
Amplificarion of a body’s response to a stimulus (e.g childbirth)
What is the pituitary gland
A gland that makes hormones to tell the body what to do
What is the hypothalamus
Part of the brain that monitors the body
How is temperature change detected
Thermoreceptors in the hypothalamus (heat loss centre/ heat gain centre)
Define endocrine
relating to or denoting glands which secrete hormones or other products directly into the blood.
What does the endocrine system do
Coordinates the body’s organs so that they work together
What are hormones produced by
Endocrine glands in different parts of the body
What do hormones do
Control body processes that require multiple organs of the body to interact for a combined affect
How are hormones transported
In the blood (endocrine system)
What does the thyroid gland do
Produces a hormone called thyroxine
What is thyroxine
Iodine combined with tyrosine
What does thyroxine do
Regulates metabolism
How does thyroxine regulate metabolism
By transferring energy from stores to make it available to cells
What is TSH
Thyroid stimulating hormone
What does TSH do
Stimulates the thyroid to release thyroxine
Step one of thyroxine
The body requires more energy so the hypothalamus causes the pituitary gland to release TSH
Step two of thyroxine
TSH travels in the blood to the thyroid gland and stimulates this gland to release thyroxine
Step 3 of thyroxine
Thyroxine causes the metabolic rate to increase
Step four of thyroxine
This (metabolic rate increase) increases the transfer of energy to cells
Step 5 of thyroxine
The cells now have the required amount of energy
Step 6 of thyroxine
Feedback is sent to the hypothalamus to stop the release of TSH
All 6 steps of thyroxine (6 marker)
1: The body requires more energy so the hypothalamus causes the pituitary gland to release TSH
2: TSH travels in the blood to the thyroid gland and stimulates this gland to release thyroxine (which is iodine and tyrosine)
3: Thyroxine causes the metabolic rate to increase
4: This (metabolic rate increase) increases the transfer of energy to cells from stores
5: The cells now have the required amount of energy
6: Feedback is sent to the hypothalamus to stop the release of TSH
How many eggs/ovums/oocytes are released and killed per hour
Two
Where is oestrogen produced
In the ovaries
Where does fertilisation occur
Fallopian tube/ oviduct
How long is the menstrual cycle (average)
28 days
On what day of the menstrual cycle does bleeding begin
Day 0
On what day of the menstrual cycle is the ovum (egg/oocyte) released
Around day 12 (9-15)
What controls the menstrual cycle?
Pituitary and hypothalamus
What is FSH
Follicle stimulating hormone
What releases FSH
The pituitary gland
What does FSH do in women
Stimulates the growth of immature ovarian follicles
(causes the maturation of an egg in the ovary)
What does FSH do in men
Stimulates the production of sperm
What is LH
Lutenising hormone
Which sex produces LH
Female
What does an increase in LH trigger
Ovulation
What does oestrogen do (3 things)
Stimulates the growth of the endometrium (uterus lining) and it’s blood supply
Inhibits further secretion of FSH
Stimulates the pituitary gland to secrete LH
What does progesterone do
Prevents the endometrium (uterus lining) from entering its secretory stage to prepare the uterus for implantation
What happens to progesterone levels if pregnancy does not occur
Progesterone levels decrease, leading (in humans) to menstruation
What does progesterone do during implantation and gestation
Decease the maternal immune response to allow for the acceptance of the pregnancy
What is ART
Assisted reproductive technology
Why do people need ART
Unable to reproduce naturally
… potentially due to low sperm count OR quality
How does ART work (7 steps)
Sperm tested
Reproductive organs examined
Woman injects herself with hormones to stimulate egg production
(Weeks later) egg retrieval
Egg checked
Creation of the embryo (sperm combined with egg in a lab)
3 days after fertilisation, the embryo is implanted
What happens if there is too much sugar in the body
Water goes out of cells through osmosis
What happens to cells if there is too little sugar in the body
Water enters cells through osmosis
What happens in the pancreas when there is high blood sugar
The pancreas is stimulated to produce insulin
What part of the pancreas produces insulin
Beta cells in the endocrine Islets of Langerhan
What happens in the liver when there is high blood sugar
Insulin stimulates the liver to take glucose from the blood and convert into glucogen, which is stored in the liver
What happens in the pancreas if there is low blood sugar
Alpha cells in the pancreas release glucagon
Where are alpha cells in the pancreas located
Islets of Langerhan
What happens in the liver when there is low blood sugar
Glucagon stimulates the liver to convert glycogen back into glucose and release the glucose into the blood stream
What are the short term problems with diabetes (2 things)
Hypoglycaemia- low blood sugar
Diabetic ketoacidosis- sugar in the urine (can cause infections because bacteria love sugar so sue them)
What are the long term problems with diabetes (4 things)
Cardiovascular disease
Retinopathy (sugar crystals forming around the eyes)- blindness
Nephropathy (kidney disease)- kidney failure
Musculoskeletal conditions- arthritis, osteoporosis
What happens if you eat too much protein
The protein is broken down into amino acids
These amino acids are broken down by the liver and make urea
Why must urea be removed
It is poisonous
How is urea removed
It passes into the blood and is filtered out by the kidneys
What is urine
Urea mixed with water
What happens if the concentration of fluids change in the body
It can cause water to move in or out of cells by osmosis
This could destroy cells
How can water levels change (4 things)
Breathing out water
Eating and drinking
Sweat
weeing
What do the kidneys remove excess of from urea
Mineral ions that can be lost in urine
What do kidneys do
Filter blood and reabsorb everything the body needs, filter out urea
What move out of the blood and into the kidneys by diffusion (4 things)
Glucose
Amino acids
Mineral salts
Urea
How is sugar reabsorbed back into the blood
with Active transport
Why does the amount of mineral ions and water reabsorbed vary
It depends on what your body needs
What is selective reabsorption
Certain molecules are reabsorbed from the filtrate as they pass through the nephron
What is urine called before it is in the bladder
Filtrate
What is the mechanism that tells the body how much water needs to be reabsorbed
Feedback mechanism releasing ADH
What filtering do the kidneys use
Pressure based filtering
Why do kidneys have a rich blood supply
To constantly produce urine
3 ways kidneys can be damaged
Infections
Genetic problems
Accidents
Ways to treat a damaged kidney (2 things)
Dialysis
Kidney transplant
What happens if the kidneys are damaged (2 things)
Toxins build up
Salt and water balance can be lost
How does dialysis work?
Blood leaves the patients body and flows between a partially permeable membrane. On the other side of the membrane is dialysis fluid
What does dialysis fluid contain and why
The same concentration of glucose and mineral ions as normal blood plasma so that there is no net movement of glucose out of the blood
What is a nephron
The functional component of the kidney
How many nephron are in each kidney
Millions
What brings blood into the kidney
Renal artery
What is ultra filtration
Doesn’t filter large molecules or blood
Bowman’s capsule- high pressure
What does ultra filtration produce
A liquid called filtrate
What occurs in the PCT and DCT
Selective reabsorption
Where does the filtrate go after selective reabsorption
Into the collecting duct then into the bladder
What is a diuretic
They make you need to excrete urine
What is osmoregulation
The control of water and salt levels in the body
Where does osmoregulation occur
In the collecting duct
What controls osmoregulation
The pituitary gland
The hypothalamus tells the pituitary gland what to do
Step one of the body combating dehydration
Decreased water potential of blood
Pure water has a water potential of 0(little trident)(small p)
More dehydrated=water potential decreases
Step two of the body combating dehydration
Osmoreceptors in the hypothalamus lose water, so they shrink
Step three of the body combating dehydration
Shrinking of osmoreceptor cells stimulates nerve cells in the hypothalamus
Step four of the body combating dehydration
Increased ADH (Antidiuretic hormone) production by posterior pituitary gland
Step 5 of the body combating dehydration
ADH carried in the blood
Step six of the body combating dehydration
ADH arrives at the collecting duct
All steps of the body combating dehydration (6 steps)
1: Decreased water potential of blood
Pure water has a water potential of 0(little trident)(small p)
More dehydrated=water potential decreases
2: Osmoreceptors in the hypothalamus lose water, so they shrink
3: Shrinking of osmoreceptor cells stimulates nerve cells in the hypothalamus
4: Increased ADH (Antidiuretic hormone) production by posterior pituitary gland
5: ADH carried in the blood
6: ADH arrives at the collecting duct
What happens at the collecting duct
ADH makes the cells more holey (creates more aquaporins (little holes that let more water in)) and filtrate comes down in collecting duct
What are the tubes in the kidney lined with
Cells that look like □□_□ to give them more surface area
