homeostasis

What is homeostasis?

The maintenance of a consistent internal environment in an organism

What part of the human body controls and detects changes in homeostasis

Hypothalamus- controls and detects changes in internal conditions to maintain a steady state

Name the 3 things that homeostasis controls and how?

Body temperature- thermoregulation via skin

Water and mineral concentration- osmoregulation via kidneys

Glucose concentration- insulin production by pancreas and glycogen conversion by liver and muscles

Functions of the skin

Physical barrier to prevent entry of pathogens

Thermoregulation

Malpighian layer

Fat/ blabber keeps marine mammals warm by providing insulation and buoyancy

Allows for blood clot formation- works closely with the circulatory system

How does thermoregulation act as a function of the skin

Hairs stand erect to trap warmth in cool climates and the muscles contract

Hairs lie flat and hair erector muscles relax

Role of malpighian layer

Produces melanin- gives us skin colour

Protects us from harmful uv rays from the sun

List the clotting cascade( formation of blood clots)

Prothrombin- inactive enzyme and has vitamin K and calcium which is needed to form blood clots

Thrombin

Fibrinogen(soluable )

Fibrin (insoluble)

Forms a mesh to trap red blood white blood and platelets to form a scab

Poikilotherm

Temperature of animals is determined by the environment ( cold blooded)

Homeotherms

Regulate their own body temperature( warm blooded)

Endotherms

Not reliant on environmental conditions( humans)

Adaptation of plants to cold climate

Leaves fall, conifers, a-shaped which allows for snow to fall off

Adaptation of plants to warm/ hot climate

Long tap roots that penetrate deep into the soil to get to the water table

Reduced leaves to form thorns which provide a reduced surface area for less water loss

Thick waxy cuticle which reduces water loss by evaporation( prevents extra transpiration)

Fewer stomata allows for limited gas exhange, it balances carbon dioxide intake and minimizes water loss

Water stored In photosynthetic stems

Chloroplasts control how much light is absorbed to undergo photosynthesis contributing to the plants energy balance

What is osmoregulation?

The maintenance of water and mineral salt concentrations in the body

Name the transport processes A to D in the process of excretion

Ultrafiltration

Selective reabsorption

Water conservation

Regulation of urine produced

What is ultrafiltration

Filtration at high blood pressure as diameter of capillary entering a glomerulus from an arteriole decreases

Only SMALL molecules pass through the glomerulus to the bowman's capsule

Plasma proteins stay in the bloodstream because they are too large

What is selective reabsorption

Useful substances are reabsorbed from filtrate into the blood traveling through the capillaries wrapped around each nephron

Glucose, amino acids, hormones, vitamins,water and salts are reabsorbed in the proximal convoluted tubule

Some water is reabsorbed in the henle loop

Some salts and water are reabsorbed in the distal convoluted tubule

How is water conservation maximized?

Longer loops of Henle allow for greater water conservation.

water is reabsorbed by osmosis and everything else by diffusion and active transport

regulation of urine

Nephrons have a network of blood capillaries wrapped around it which leads from the glomerulus and joins into a venule leading to the renal vein. nephrons join in collecting ducts in the cortex leading through the medulla and out into the pelvis.

when urine is made it travels down the collecting duct to the ureter and then the bladder where it is stored.

What happens when body fluids become too concentrated?

Hypothalamus detects that blood plasma is too concentrated

anti diuretic hormone regulates the concentration and volume of urine produced from a signal from a pituitary gland. The distal convoluted tubule and collecting ducts become more permeable. most waters reabsorbed into the blood and smll quantities of concentrate urine are produced.

What happens when body fluids become too dilute?

the hypothalamus detects it and the pituitary glands stops secreting anti diuretic hormone. without it the walls of the distal convoluted tubule and collecting ducts stay impermeable so very little water is reabsorbed into the blood. large quantities of dilute urine are produced.

What is excretion

the process by which waste and harmful substances produced by the body's metabolism is removed from the body.

What is your metabolism made up of?

Anabolism(build up) + catabolism( break down) reactions

useful substances in plants

Oxygen from photosynthesis at day

H2O from respiration at night

Harmful substances in plants

CO2 from aerobic respiration

Calcium oxalate crystals

Tannins, alkaloids and anthocyanins come from nitrogenous wastes

Useful substances in animals

H2O from aerobic respiration to maintain body temperature

Heat maintains body temp

Harmful substances from animals

CO2 from aerobic respiration

Nitrogenous compounds via deamination by liver (ammonia, urea, Uric acid)

Bile from breakdown of haemoglobin from red blood in the liver

Excretory organs on animals

Skin-sweat( water urea and salts)

Liver-deamination(urea and bile)

Lungs- water and carbon dioxide

Kidneys-urine(nitrogenous waste mainly urea, water and salts)

Excretory mechanisms in plants

Stomata- gaseous diffusion of oxygen and carbon dioxide and water vapour( lenticels of trees with bark)

organic waste products(nitrogenous waste) can be stored in dead permanent tissue. they can also be converted to insoluable substances such as oils or insoluable crystals(excess calcium ions combines with waste product oxalic acid to form calcium oxylate crystals). they are stored in leaves barks petals fruits and seeds to be shed.

Medicine can be derived from other wastes

The liver is the site of…

Transamination and deamination

What is transamination?

The reassembling of amino groups to form different amino acids and proteins

What is deamination

The removal of amino acids( -NH2) to form urea: CO(NH2)2 vis the orithine cycle

What does urine consist of

Urea and water

Name the 3 types of movement

Whole- entire organism location

Part- limbs can move eg, forearm flexes and extends

Growth(tropisms in plants)- shoots grow towards light they are positively phototrophic