Homeostasis
General features of homeostasis, how homeostasis is regulated, negative feedback loop, thermoregulation (mechanism of animals), osmoregulation (mechanism of animals), glucose regulation (mechanism of humans)
General features of homeostasis, how homeostasis is regulated, negative feedback loop, thermoregulation (mechanism of animals), osmoregulation (mechanism of animals), glucose regulation (mechanism of humans)
Fichier Détails
| Cartes-fiches | 28 |
|---|---|
| Langue | English |
| Catégorie | Biologie |
| Niveau | Université |
| Crée / Actualisé | 09.01.2020 / 13.01.2020 |
| Lien de web |
https://card2brain.ch/box/20200109_homeostasis
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General features of homeostasis (6)
Needs:
Set point (eg temp. of 37 C)
Detector (eg temperatur sensors)
Control centre which decides what to do next
Regulatory mechanisms to carry message from control centre
Effectors or mechanisms to change factor (eg shivering)
Often involves negative feedback loops
Feedback loop (composition (what is it, how it brings features back to set point)
Receptor (observe controlled condtition and detect changes) -> control centre (determines next action) -> effector (receives directions from control centre & produces response to put the condition back to normal)
Nervous system (what does it control? (2), example)
Bodily activities that require quick response, detects changes in external environment and initiates reactions
Body temperature
Endocrine system (hormonal system) (what does it control? (3), example)
Regulation of activites with long duration, control of concentration of nutrients, through regulating the kidney function -> control of internal environment's volume and electrolyte composition
How does fat,fur, hair insulate animals?
Blubber is a layer under the skin which keeps them warmth, as well as fur and hair adaptations (cold area -> more fur/hair, hot area -> less fur/hair)
How does evaporation cools animals (3)?
Primary method to cool down
Sweating = Sweat glands releases water onto the outer surface of the skin and this water then evaporates and cools the skin down
Panting = Release heat through mouth
Bathing = Elefants splashes water over him and cools down
How does shivering increase temperature?
Actin & Myosin interaction and ATP hydrolysis
Muscles bound - not bound - bound ... quick crossbridging of muscles
uses a big amount of energy
Heat generation -> maintains our body temperature
How does brown fat and thermogenesis (heat production in cells) allow thermoregulation?
Brown adipose tissue produces heat by non-shivering thermogenesis
Thermogenine is located in mitochondrial membrane of brown fat cells
It uncouples proton movement from ATP -> Energy change produces heat instead of ATP molecules
Brown fat contains of more capillaries than white fat, these capillaries supply oxygen and nutrients and distribute the heat throghout the body
Physiological impacts of hibernation (3)
Low metabolic rate
Slow breathing
Slow heart rate
Physiological impacts of torpor (4)
Lower metabolic rate
Lower breathing rate
Lower heart rate
Lower body temperature
Difference between hibernation and torpor (2)
Torpor is much shorter than hibernation
Torpor happens unintended without control and when the external conditions dictate it
Vasoconstriction & Vasodilation
Vasoconstriction = The skin is more pale because the blood is not flowing close to the surface to prevent heat loss (winter)
Vasodilation = The blood flows closer to the skin surface to lose heat. The cooled blood then flows back to the heart. (summer)
Counter current exchange (in goose leg, dolphin flipper, wales tongue)
Parallel pipes of liquid flowing in opposite directions to save energy
Exchange of small gradients to not loose too much heat.
Concurrent exchange
Parallel pipes of liquid in the same direction.
Large gradients disappear quickly so more energy is lost
Osmoregulation (definition)
The regulation of concentration of body fluids
Diffusion (definition)
Movement from an area of a greater to a lower concentration
Osmosis (definition)
Diffusion of water through a semipermeable membrane
Osmolarity (definition)
The concentration of a solution expressed as the total number of solute particles per litre
Hypoosmotic marine fish (saltwater habitat) adaptations (4)
Lose water by osmosis
Gain ions by diffusion
Drink water
Less salt internally than externally
Hyperosmotic freshwater fish (4)
Doesn't drink water
Gain water by osmosis
Lose ions by diffusion
Internal more salt than external
Osmoconformer hagfish
Sewater concentration = Internal concentration of hagfish
Very slimy!
Salt glands (crocodiles & gulls)
Located in nasal area and excrete excess salt
Nephron
Small party which build the kidney
Key hormones in osmoregulation (4) (function of first)
ADH = arginine vasopressin = tells kidney's how much water to conserve
Renin
Angiotensine
Aldosterone
Where is glucagon and insulin specifically produced?
They are produced in a islet of langerhans region in the pancreas , which contains insulin producing beta cell and glucagon producing alpha cell.
Role of insulin in glucose uptake in respiratory cells
When glucose is present, insulin gets released and binds to insulin receptors on cells (liver, brain). This causes glucose transporters (GLUT 1,2,3,4) (membrane proteins in vesicle) to move up to the cell membrane to increase the glucose transport into the cell.
If this works wellm glucose gets transported into respiratory cells. -> insulin increases respiration
Main functions of insulin (3)
Release of insulin when blood sugar (glucose) is high
Facilitates the transport of glucose into targer cells
Promotes energy storage in fat cells
Main functions of glucagon (2)
Glucagon is released when blood sugars (glucose) are low
Causes liver to convert glycogen (polysaccharide with many branches) into glucose, which then gets released into the bloodstream
