5.1.2 Flashcards
What is excretion?
removal/processing of waste from body
unwanted products of metabolism
What is metabolic waste?
waste produced from metabolism
C02, urea
What is egestion?
removal of undigested waste by defcation
What is deamination?
Removal of ammonnia from amino acids
What is secretion?
process by which substances are produced and discharged from a cell, gland, organ for a particular function in the organism
Why do CO2 and urea need removing?
toxic and would cause damage if not removed
What happens if CO2 is not excreted?
hydrogen carbonate ions can reduce the ability to transport oxygen
forms carbaminohaemoglobin which has a lower affinity for oxygen than normal haemoglobin
Respiratory acidosis - drop in blood pH
How does the body remove excess amino acids?
deamination
forms a soluble, highly-toxic compound ammonia
Ammonia converted into less soluble and less toxic compound called urea
urea transported to kidneys for excretion
What is the overall reaction equation for deamination of excess amino acids?
Ammonia + CO2 = urea + H2O
Where is the liver located?
below diaphragm
How many blood supplies does the liver have?
2
What are the 2 blood supplies that the liver has?
Hepaptic artery
Hepaptic portal vein
How does the hepaptic artery supply blood to liver?
brings oxygenated blood from the aorta
How does the hepaptic portal vein supply blood to liver?
delivers deoxygenated blood from the digestive tract
contains toxins and nutrients so liver can clean toxins
What happens to blood leaving the liver?
blood is carried away by HV to vena cava
Why does the hepaptic vein carry blood away from the liver at a lower pressure?
the network of capillaries in the liver have a large surface area
What are the structural differences between hepaptic artery and hepapatic portal vein
HPV has a wider diameter - wider lumen
What are sinusoids ?
connect HA to HV allowing hepatocytes to remove harmful substances from blood
What are lobules?
contain hepatocytes
arranged in irregular branches, interconnected plates around a central vein
as blood enters liver from HA and HPV they go into smaller and smaller vessels
What cells form bile?
hepatoyctes
What is the bile duct?
takes bile from the liver to the gall bladder
What is a kupffer cell?
attached to the walls of the sinusoid, they remove bacteria and break down RBC
break down Hb to make billrubin which is excreted in bile and in faeces to make a brown pigment
What does bile canal do?
connects the vein to the bile duct
What is the orinthine cycle?
reactions that convert ammonia into urea
What is detoxification?
removal of toxic substances
WHAT IS THE EQUATIOn for deamination?
Amino acid + oxygen = keto acid and ammonia
Outline deamination?
Use excess amino aicds
amine group of each amino acid is removed
Ammonia is formed which is highly soluble and highly toxic
Keto acid can enter respiration to release energy or stored as fat
How does urea become urine?
Transported from the liver to the kidneys in the blood stream where it is ecreted dissolved in water as urine
Outline the orinthine cycle?
Ammonia is added and water is formed - condensation, uses ATP
water is added and urea is formed - hydrolysis
ammonia and CO2 are added and water is formed -condensation, uses ATP
What is the process of ultrafiltration?
Afferent arterioles has a larger diameter than the efferent arteriole
therefore generating hydrostatic pressure
the endothelium wall of the capillary has small pores/fenestrations
Why is fluid pushed out the glomerulus and into the Bowman’s capsule?
Pressure is higher in the glomerulus than in the Bowman’s capusle
which pushes fluid into the capsule
What is the glomerular filtrate?
fluid in the renal capsule
What is the endothelium / fenestartions?
narrow gaps which allow blood plasma and substances to pass through
What is the basement membrane?
stops the removal of large substances from thhe blood
What are podocytes?
finger-like projections
ensure passage of substances
Why does odemia happen?
higher blood pressure forces too much fluid out into the glomerular filtrate
protein in the urine caused by damage to basement membrane
arterial hypertension
Where does Selective reabsorption happen?
PCT
What is selectively reabsorped and how?
all glucose and amino acid
by facilitated diffusion
What is the process of selective reabsorption?
1) Na+ actively transported out of cells into tissue fluid
2) Glucose or amino acids enter cells with Na+ by F.D
3) glucose and amino acids diffuse into blood capillary
How is water reabsorbed into blood?
osmosis
salts, glucose and amino acid reabsorbed?
reduced water potential of cells
inc w.p in tubule
What happens in the aSCENDING LIMB?
Na+ and Cl- are actively transported out of the loop of henle
decreasing the water potential of the surrounding tissue in the medulla
water potential of tissues surrounding the collecting duct s lower than the fluid inside
What happens in the descending limb?
the movement of ions causes a decreases in water potential going down the medulla
walls are permeable to water
water is removed from the descending limb
by osmosis into the surrounding tissue
What happens in the collecting duct?
Water is removed from urine
Why does an animal living in the desert have a longer loop of henle than a human?
needs a steeper water potential gradient
so water can reabsorb as much water as possible
by creating very low water potential
What is the process of osmoregulation?
The osmoreceptors in the hypothalamus detect a low concentration of water in the blood
ADH is released from the posterior pitutiary gland transported to the kidneys in the blood
What is the effect of ADH on the collecting duct wall?
1) ADH detetced by cell surface receptors
2) Enzyme controlled reactions
3) VESICLES containing water-permeable channel aquaporins fuse to membrne
More ewater can be reabsorped
What are aquaporins?
instrinsic protein pores
What happens as a result of low ADH levels?
cell surface membrane folds inwards - creating new vesicles
remove the aquaporins making the membrane less permeable
urine is more diulte
How does pregnancy testing worl?
1) dip stick into urine
2) hCG has a complimentary shape to the monoclonal antibodies , hCG bonds to the monoclonal antibodies to form a hCG antibody complex which moves up the stick with the urine
3) excess antibodies carried up with the urine bind to the immobilised antibopdies in the upper band - this is a control
4) hCG complex binds to immobilized antibodies due to the complimentary shape in the lower band if the woman is preganant
2 lines = pregnant
1 line = NOT
What are anabolic steroids?
large molecules built from smaller ones
What are steroids derived from?
cholesterol
lipid-soluble
increase protein synthesis insdie the cell
hOW DO WE TEST ATHLETES FOR STEROIDS?
URINE PASSED THROUGH GAS CHROMATOGRAPHY
to create chromatogram
