Unit 7 - Animal Coordination, Control And Homeostasis Flashcards
What does your nervous system enable you to do?
Respond quickly to changes in your surroundings
What does your hormonal system allow you to do?
Cause responses in many parts of your body but is much slower
How does the hormonal system send messages
It uses chemical messengers called hormone which are carried by the blood
What type of glands produce hormones?
Endocrine glands
What gland releases the hormones ACTH, FSH, LH and growth hormone
The pituitary gland
What hormone does the thyroid gland release
Thyroxine
What gland releases adrenaline?
Adrenal gland
What hormone do the testes release?
Testosterone
What hormone does the pancreas release?
Insulin
What hormones do the ovaries release? (2)
Oestrogen and progesterone
What is a target organ?
An organ affected by a specific hormone
What effect does a hormone have on an organ
It changes what the organ is doin
Why do people end up growing more during puberty?
The sex hormone stimulate the release of the growth hormones
What is your metabolic rate?
The rate at which the energy stored in your food is transferred by all the reactions that take place in your body
How is your resting metabolic rate measured?
With the body at rest, in a warm place and long after they have a meal
What hormone affects your metabolic rate?
Thyroxine
What are 2 effects of thyroxine?
Causes heart cells to contract faster
Increases rate of proteins and carbohydrates being broken down
What is negative feedback?
When there is an increase in something which directly causes a change to decrease it or vice versa
What is the order of glands involved in the negative feedback of thyroxine (and hormone released)
Hypothalamus (TRH)
Pituitary gland (TSH)
Thyroid gland (Thyroxine)
Target organs
What situations is adrenaline released?
Frightening or exciting situations
What is the process involved in Adrenalin being released
In flight or fright situations, more impulses from the neurones reach the adrenal glands from the spinal cord which releases large amounts of adrenaline into the blood
What does the breaking down of glycogen allow
More glucose molecules released into the blood for respiration
What are the 3 target organs for adrenaline?
Heart
Liver
Blood vessels
What effect does adrenaline have on the heart
Cells contract more rapidly, increase heart rate
Contract more strongly, increases blood pressure
What affect does adrenaline have on the liver
Breaks down glycogen to glucose and releases it into the blood, increases blood sugar concentration
What is the effect of adrenaline on the blood vessels (widening)
Widens the diameter, increases blood flow to muscles
What is the effect of adrenaline on the blood vessels (narrowing)
Narrows diameter , reduces blood flow to organs and increases blood pressure
What is the menstrual cycle?
A cycle of changes in a woman’s reproductive system that takes around 28 days
When does the menstruated cycle happen?
From puberty to menopause
What happens between days 1 and 5 of the menstrual cycle?
The uterus lining breaks down and the unfertilised egg cell is lost
What happens between days 6 and 12 of the menstrual cycle?
The uterus lining starts to thicken again
What happens between days 13 and 15 of the menstrual cycle?
Ovulation, when the ovary releases the egg
Between what days is it most ideal for fertilisation?
16 and 21
After day 23 of the menstrual cycle, what happens
The egg cell travels along the oviduct to the uterus
What hormones control the menstrual cycle?
Oestrogen and progesterone
At what point of the menstrual cycle does the concentration of oestrogen decrease?
Ovulation
What is contraception
The prevention of fertilisation
What does the hormone pill or implant placed under skin do?
Releases hormones to prevent ovulation and thickens mucus at the cervix, making it difficult for sperm cells to pass through
What does FSH stand for
Follicle-stimulating hormone
What does LH stand for
Luteinising hormone
What are FSH AND LH released from the
The pituitary gland
What controls the release of FSH and LH?
The concentration of oestrogen and progesterone
Where is the pituitary gland?
At the base of the brain
How does oestrogen and progesterone control FSH and LH?
Low levels of progesterone allows FSH to be released
High levels of oestrogen allows more LH to be released
What does FSH stimulate?
Growth and maturation of egg follicle
Oestrogen production
What does LH stimulate?
The release of the egg (ovulation)
Progesterone
What does oestrogen do?
Causes uterus wall to thicken
Stimulates LH surge
What stimulates oestrogen production?
Maturing follicle, FSH increase
After ovulation, what is the name of the structure in which the egg follicle becomes
Corpus luteum
What causes progesterone to be released?
LH
What does falling oestrogen and progesterone levels trigger
Menstruation
Why does hormonal contraception using progesterone and oestrogen work?
Higher levels of the hormones prevents the start of a cycle occurring
What does assisted reproductive technology allow?
It overcomes some problems to help a woman become pregnant
What is clomifene therapy?
A drug that helps to increase the concentration of FSH and LH in the blood
What does IVF stand for?
In vitro fertilisation
What happens in IVF?
FSH and LH injected into body to mature egg follicle
Egg follicle matured by hormones
Egg cells released and taken from the ovary
Sperm cells taken from man
Eggs and sperm combine to allow fertilisation
One or two healthy embryos placed in uterus
What test can be used for diabetes?
A urine test
In the Middle Ages, how did doctors test for diabetes?
Tasting the urine
What happens to glucose in our body
During digestion in the gut, glucose is released from carbohydrates in our food. It is easily absorbed from small intestine into the blood and then into cells where it is broken down for respiration
Why is there a risk that glucose may reach a very high concentration in the blood
It takes time for cells to take in the glucose
How is blood glucose concentration controlled?
When the concentration rises, the pancreas responds by releasing insulin which causes the liver and other organs to take in glucose so the concentration falls
What happens to glucose after it is absorbed by the liver
It is converted to glycogen
What happens in the liver if the glucose concentration falls too low
A hormone called glucagon is released from other pancreatic cells which cause liver cells to convert glycogen back to glucose
What is homeostasis?
Maintaining constant conditions inside the body
Give 2 other examples of homeostasis besides glucose concentration
Temperature control and water content
What is Type 1 diabetes?
When the pancreatic cells do not produce insulin so they cannot control rising blood glucose concentration
Why is a urine test the first test for type 1 diabetes?
Glucose can be detected in the urine
How do people with type 1 diabetes control the glucose concentration
They have to inject insulin into the fat layer below the skin where it enters the blood
What is Type 2 diabetes
When either the insulin-releasing cells are not producing enough insulin or the target organs are not responding to the insulin
For people with less severe type 2 diabetes, give 2 ways in which they can control it
Eating healthily (low amount of sugar) Being physically healthy, takes glucose out of the blood
How might people with more severe type 2 diabetes be treated?
Given medicines to reduce amount of glucose that the liver releases into the blood or to increase sensitivity of target organs
Why do scientists use BMI rather than mass to see the risk of type
2 diabetes?
BMI takes into account the different heights
What is the equation for BMI
BMI = mass (kg) / height^2 (m)
What is the BMI for obese
Over 30
What is the BMI range for a normal person
18.5 - 24.9
What are the 2 measurements that link to obesity?
BMI and waist:hip ratio
How do you work out your waist:hip ratio
Waist/hip
Why does waist:hip ratio correlate with type 2 diabetes?
Ass people increase in mass, they develop more fat around their waist
What is the normal temperature for the human body
Around 37 degrees Celsius
What temperature is considered a fever
Above 38 degrees
What temperature is considered as hypothermia
Below 36 degrees
Why are fevers and hypothermia dangerous
They affect how well the enzyme sin our bodies work
What is thermoregulation?
The control of body temperature
What is the hypothalamus?
A small part of the brain that constantly monitors temperature
How does the hypothalamus process work?
It receives information from temperature receptors in the dermis of the skin
What is shivering
When muscles contract and relax rapidly, some of the energy release from cell respiration for shivering warms you up
How does hair keep the body warmer
Contraction of erector muscles in the dermis of the skin causes hair to stand upright which would trap warm air for other mammals
How does the reduction of blood flow near the skin keep the body warmer
It keeps warm blood deeper inside the body which reduces the rate of transfer of energy to air by heating
How does sweating keep us cooler?
When the hypothalamus detects temperatures above 37 degrees, sweat spreads out as a thin layer over this skin epidermis which evaporates and transfers energy from the skin to the air by heating
How does the skin respond when the body temperature is too low (2)
Hair is pulled upright by erecting muscles
Reduced blood flow to skin
How does the skin respond when the body temperature is too high? (3)
Sweat evaporates
Hair lies flat
Increased blood flow to skin
What is vasoconstriction
When the blood vessels are narrowed when it is too cold, reduces energy transfer to surroundings
What is vasodilation?
When the blood vessels are widened to bring warmer blood to surface of skin to increase energy transfer by heating to surroundings
What is osmoregulation?
The control of the balance of water and mineral salts in the body
Why can the wrong amount of water in the body be dangerous? (2)
Water in cells allows all the molecules in the cell’s reactions to move around
It is needed to maintain the shape of the cell
What is the function of the urinary system?
To remove excess amounts of some substances from the blood including water and mineral salts
To remove waste products such as urea
What is urea?
Produced on liver cels from the breakdown of amino acids that are in excess
What is the role of the ureters
To carry urine from the kidneys to the bladder
What is the role of the bladder
To store the urine
What is the role of the renew arteries
To carry blood from the body to the kidneys
What is the role of the kidneys
To remove substances from the blood and make urine
What is the urethra
What the irony flows through to the outside of the body
What is kidney failure?
When both kidneys stop functioning
Why is a persons life in danger if they have kidney failure?
Waste substances increase in concentration in the blood
What are the 2 options to treat kidney failure?
Dialysis, kidney transplant
How does a dialysis machine work?
Blood carrying wastes passes to the machine from a vein
The machine removes the waste and is put back into a vein
Why is the dialysis fluid personal to each person
It contains the same concentration of glucose as blood
What 2 diffusions happen in dialysis?
Equal for glucose
Diffusion out of the blood for urea and waste substances
Why might a kidney donor not be successful for patient? (2)
Too weak for the long surgery
Antigens on cells are rejected by immune system
What risk comes with a successful kidney donor?
They need life long medication to stop rejection which can affect the immune system making them more vulnerable for infection
What are nephrons
The microscopic tubes found in each kidney
Where is urine made?
In the nephrons
What is the glomerulus?
The network of capillaries in which blood flows through in the kidneys
What is the bowmans capsule?
What the capillaries run through in the kidneys
What is the bowmans capsule and glomerulus adapted to do?
To let very small molecules like water, urea and glucose through into the nephron
What is filtration
The process in which only certain molecules are let through
What happens to the filtration fluid after it has been filtered?
Selective reabsorption of useful substances such as glucose and mineral ions
What happens in the first convoluted tubule?
The reabsorbed substances are pumped through proteins in cell membranes by active transport
How is water reabsorbed in the kidneys.
By osmosis
Where is the water reabsorbed in the kidneys?
Loop of Henle and collecting duct
At the end of the nephron, what does the remaining fluid contain? (3)
Excess water, urea and other substances
Give 3 ways in which a nephron is adapted for reabsorption of certain substances
A large surface area of contact between the nephron and capillaries
Cell membrane of the fist convoluted tubule has Microvilli
Cells that protein pumps into their membranes contain many mitochondria
As well as getting rid of urea, what does the kidneys also control
The water content of the blood
What gland detects the amount of water?
Pituitary gland
What does the pituitary gland do when it detects too little water
It releases the hormone ADH
What does the hormone ADH do?
It changes the permeability of the collecting duct in nephrons and increases the concentration of urine (less water)
What is the role of oestrogen?
Building up of the uterus lining
What is the role of progesterone?
Maintaining of the uterus lining
What causes the uterus lining to break?
Low levels of progesterone (not maintained)
What is the role of renal veins?
To carry the cleaned blood from the kidneys back to the body
What does progesterone do
Maintains the uterus lining
