B12 - Homeostasis In Action 2️⃣✅ Flashcards
Where is the themoregulatory centre?
In your brain, in a particular part of the hypothalamus
How do mammals regulate there temperature?
They are warm blooded, therefore there temperature is independent from the environment. There enzymes work at optimum temperature on there own
How do reptiles, amphibians & fish regulate there temperarture?
They are cold bloded, therefor ethere temperature is not independed from the environment - therefore there body temperature relies on the tperature of the envrioinment
What is vasodilation?
When your blood vessels that supply your surface skin capilaries dilate (open wider) and lets more blood flow through the capilaries. Therefore releasing more heat energy by radiation from your skin to the surroundings, consequently cooling you down.
What is vasoconstriction?
When your blood vessels that supply your surface skin capilaries constrict (close up) and reduces the flow of blood through the capilaries. Therefore reducing the energy transfer by radiationm, consequently keeping you warm.
What 3 things happen when you loose heat?
- Vasodilation
- Producing sweat from sweat glands
- Hair erector muscles relax
What happens to hair when you try to loose heat/ cool down?
Hair erector muscles relax and make the hairs lie flat against the skin, less air is trapped near skin surface, more heat lost by radiation
What happens to hair when you try to reduce heat loss/ keep warm?
Hair erector muscles contract and make the hairs stand upright against the skin, this traps warm air near skin surface, less heat lost by radiation
What happens with sweat when we try to loose heat?
Producing sweat from sweat glands, extra sweat to evapourate on the skins surface
What happens with sweat when we try to reduce heat loss?
Sweat glands stop producing sweat
What 3 things happen when you reduce head loss?
- Vasoconstriction
- Shivering
- Hair erector muscles contract
What happens with shivering when we try to reduce heat loss?
Skeletal muscles rapidly contract and relax, causing you to shiver. This requires alot of respiration, and exothermic process. The energy transferred from the exothermic reactions raisees your body temp until shivering stops
Where are the 2 locations of thermoreceptor cells in your body?
- The skin - they detect extreme temperature changes
- The brain (thermoregulatory centre) monitor temperature of blood as the blood flows through the brain
What does the kindey do?
- Excretes urea by filtering
- controls water & mineral ion/slat balance (osmoregulation)
- Ultrafiltration
- Selective Reabsorption
Label this kindey
- Renal artery
- Renal vein
- Ureter
- Renal Cortex
- Renal Medulla
- Pelvis
What does the pelvis do?
The pelvis is where the urine is collected
What does the renal medulla do?
Makes the urine
What direction does blood flow in the renal artery & what does it contain?
Blood flows into the kidney with a high 02, urea, glucose, water & mineral ions/salt concentration
What direction does blood flow in the renal vein & what does it contain?
Blood flows out of the kiney with a low 02 concentration, no urea and low glucose, water & mineral ions/ salt concentration
Where does the ureter lead?
Down to the bladder to store urine
What does the renal cortex do?
Filtering
What happens to excess amino acids?
They are sent to the liver in the blood where they will be processed into urea which is then sent to the kindney where they are filtered and excreted in urine
How can you tell that someone has got diabetes from there urine?
When excess glucose (sugar) can be found in urine. This implies that the persons body cannot control blood sugar levels, therefore the kidney has an influx in sugar/ glucose from blood so some of it remains in urea & therefore is excreeted in urine
What does ultrafiltration do?
Ultrafiltraion occurs in the renal artery (coming into kidney). Blood is put under high pressure forcing water and all small molocules through the partially permeable kidney tubule membrane. Urea, water, mineral ions & glucose can fit through. And leaving large moloucles in the bloodstream e.g. RBC & Proteins
What molocules can’t fit through the partially permeable membrane?
Proteins and red blood cells can’t fit through the memrane, they are too large
What molocules can fit through the partially permebale membrane?
Glucose, water, mineral ions & urea can fit through the membrane because they are small molocules
What is the order of processes that occur in a kidney tubule?
- Ultrafiltration
- Selective Reabsoption
- Active transport
- Excretion
What is selective reabsorption?
Because we dont want to excrete usefull small molocules like water, mineral ions or especially glucose, the tubule will undergo selective reabsorption and the molocules will diffuse from the high concentration of the tubule (full of glucose, water, mineral ions etc) and back into the blood that has a very low concentration (as they had previously all left into the tuble), down the concentration gradient, so that they arent wasted/ excreted in urine.
What happens to the remianing glucose in selective reabsoption?
To ensure all the glucose is not wasted/ excreted in urine because it is used in respiration, the glucose undergoes active transport. The glucose moves from the now low concentration of glucose in the tubule to the higher concentration of the blood via active transport, going against the concentration via the protein carriers (& energy from respiration)
What actualy gets excreted in urine?
After all the kidney filtering, excess water, mineral ions and ALL THE UREA is sent down the ureter to the bladder in order to be excreted as urine
What is a kidney transplant?
A process when someone recives a kidney from another person because on of theres doesnt work properly
Which part of the transplanted kindey cells are detected by white blood cells?
antigens
What attacks the donors kidney cells?
antibodies
Why are patients of a kindey transplant given immunosuppresant drugs?
To decrease the chance of rejection from the patients body
What is a side effect of an immunosuppresant drug?
You are prone to more disesase as your immune system is ‘suppresed’
What is compared to the patients cells when decididng a donor kindey?
Antigens
Why is it important that dialysis fluid is replenished?
Because if the fliud remains the same, urea concentration would build up, therefore there would be a higher urea concentration in the fluid, preventing the urea inside the blood from diffusing into the fluid
Why does the dialysis fluid have the same glucose and mineral ion concentration as the blood?
So no glucose and mineral ions diffuse out of the blood into the dialysis fluid & therefore are wasted
Why is there no urea in the dialysis fluid?
Because the urea needs to be in a higher concentration in the blood so it will diffuse down the concentration gradient, from a high concetration to a low concentration and therefore out of the bloodstream into the dialysis fluid.
What are some negatives for dialysis?
It is required multiple times a week and can cause blood clots & can lead to infection
What are diuretics?
Medicines that help reduce fluid buildup in the body
What are antidiuretics?
Medicines that increase fluid buildiup in the body
What hormone is water loss controlled by?
Anti-Diuretic Hormone (ADH)
Where is ADH secreted?
The pituitary gland
What does ADH do?
It alters the permeability of the kidney tuble membrane to absorb more water back into the blood stream
In order to conserve water ________ ADH is released
More
When water is lost ________ ADH is released
Less
What happens when less ADH is released?
Less ADH less water is reabsorbed into the body and more urine is made
What happens when more ADH is released?
- More ADH more water is reabsorbed and less urine is made
What will happen if we have too much water in cells?
Cells will burst
What will happen if we have too little water in cells?
Cells will shrivel up
