C15 (Homeostasis) Flashcards
Excretion
Removal of metabolic waste products from the body
What are the main metabolic waste products for mammals (3)
CO2 (waste products in cellular respiration, excreted from lungs)
Bile pigments (formed from breakdown of haemoglobin, from old red blood cells) in the liver to the small intestine
Nitrogenous waste products (urea) formed from breakdown of excess AA’s by the liver, kidney excretes in urine.
What does the liver have
A rich blood supply
Hepatic artery function
Supplies the liver with oxygenated blood (for the hepatocytes)
25% blood being supplied
Hepatic vein
Drain, removes the deoxygenated blood out, back to heart through inferior Vena Cava
Hepatic portal vein
Supplies blood loaded with products of digestion (nutrients) straight from intestine (75% of blood being supplied)
Kupffer Cells
Act as the local/ resident macrophages
First line of defence
List features of heptosytis cells
Singular, hepatocyte
Large nuclei
Many mitochondria
Prominent Golgi apparatus
In general they’re metabolically active
Sinusoid
Where the oxygenated blood from the hepatic artery and the deoxygenated blood from the hepatic portal vein mixes
Branch of bile duct function
Carries bile (produced by the hepatocytes) to the gall bladder
Bile, canaliculus
Hepatocytes secrete bile , which drains into the gall bladder, stored
What does mixing the blood in the sinusoid result in
Increase the oxygen content of the blood, supplying enough oxygen needed by the hepatocytes
Kupffer cells function
Ingesting foreign particles and helping protect from disease
How’s bile produced
Bile secreted by the hepatocytes from the breakdown of blood into spaces called canaliculi
List 3 functions of the liver
Carbohydrates Metabolism
Detoxification
Deamination of Excess AA’s
Carbohydrate Metabolism
Hepatocytes, homeostasis control glucose levels by their interaction with insulin and glucagon
Glucose increases, insulin levels increase, stimulating hypatocytes covert glucose to glycogen (vise versa, glycogen converted back under influence of hormone glucagon).
Detoxification
Urea and other metabolic pathways produce poisonous substances (consumption alcohol and drugs)
Liver detoxification them (harmless)
Detoxifying ethanol, hepatocytes contain, alcohol dehydrogenase, breaks down ethanol to ethanal, ethanal to ethanoate.
Deamination
-Excess, through eating and digesting proteins.
-Nitrogen is present in amino group
-Cant usually be stored so must be used (protein synthesis) or broken down and excreted to prevent damaging body.
Anatomy of the kidney
Renal pelvis
Renal medulla
Renal cortex
Ureter
Renal vein
Renal artery
Calyces
Which part of the nephron is the most water reabsorbed into the blood
Proximal convoluted tubule
Walls are impermeable to water
Ascending limb (Loop Henle)
ADH acts on the walls of…
The distal convoluted tubule and collecting duct
What are the main functions of the kidney
-Filtering blood
-Producing urine
-Mainting water levels in body
-Regulating red blood cell levels and blood pressure
Homeostasis
Maintaining optimum internal conditions, despite changes in external environment
What do homeostasis mechanics require to function
Require information transferred between different parts body (communication systems, nervous systems: Nervous and Endocrine systems)
Give 6 examples of physiological factors controlled by homeostasis in mammals:
-Core body temp
-Blood pH
-Conc glucose in blood
-Conc respiratory gases in blood
-Water potential of blood
-Meatabolic waste
Importance of Homeostasis
Help organisms keep their internal body conditions within restricted limits
Why is a stable body temp and pH level essential
Vital for enzyme activity
Negative feedback
If increase detected, responses lower levels back to ideal conditions
If decrease detected, response raise levels back to stable condition
Negative feedback
Examples
-Controlling glucose conc levels
-Body temperature
Positive feedback
Conditions change
Change is detected
Response reinforces change
Positive feedback
Examples
-Blood clotting cascade
-Childbirth, hormone oxytocin (stimulates the uterus to contract)
What are advantages of endotherms (3)
-Can maintain temp regardless of external environment
-Remain active even at low external temp
-Inhabit colder parts of the planet
Disadvantages of endotherms (3)
-Use significant proportion of energy intake to maintain body temp in cold (less for growing)
-Need more food
-Overheating risk
Advantages of ectotherms (3)
-Less food used in respiration, more energy and nutrients from food used for growth
-Need to find less food
-Can survive long period without food
Disadvantages of ectotherms (2)
-Less active in cool temp
-High risk predators can’t take advantage of food