excretion

Front

define excretion

Back

excretion is a process by which metabolic waste products and toxic substances are removed from the body of an organism

Front

what is metabolism

Back

metabolism is the sum total of all chemical reactions occurring in the cells of an organism,

anabolism and catabolism make up metabolism

anabolism is the metabolic reactions where simple molecules are built up into complex molecules with a net intake of energy

catabolism is a metabolic reaction where complex molecules are broken down into simple molecules with a net release of energy

metabolism produces metabolic waste products which are unwanted products from metabolic reaction and are harmful if allowed to accumulate in the body --> hence must be removed or deposited as harmless insoluble substances

Front

excretion vs egestion

Back

gestion is the process of removing waste substances mainly undigested matter from the alimentary canal, undigested matter have never been absorbed into cells hence they arent produced by metabolic reactions occurring within cells

excretion --> removal of waste products produced from metabolic reactions occurring within cells

Front

excretion in unicellular vs mutilcellular organisms

Back

in unicellular organisms, they diffuse their metabolic waste products into surrounding water

for multicellular organisms, we require special excretory organs

Front

excretory organs + what they excrete

Back

1: lungs--> excrete carbon dioxide from tissue respiration and water vapour from respiration and other chemical reactions in the body in the form of gas in exhaled air.

2: kidney --> excretes nitrogenous waste/ urea from the deamination of excess amino acids (happens in the liver) and excess mineral salts from diet or neutralisation reactions and excess water from repsiration and other chemical reaction in the form of components of urine

3: skin --> excretes small amounts of nitrogenous waste products from deamination of excess amino acids , mineral salts from diet and neutralisation reactions, excess water from respiration and other chemical reactions in the form of sweat

4: liver : prdouces nitrogenous waste by deamination of excess amino acids, and it excretes bile pigments from the breakdown of haemobglobin in the form of faeces

Front

function of healhty kidneys

Back

1. 1. remove mainly nitrogenous waste products and excess water and mineral salts in the form of urine

2. 2: regulate the salt and water balance of blood plasma as an osmoregulator

3. 3: maintain the pH and composition of the blood plasma.

Front

what are the parts of the urinary system

Back

1: kidney which is a bean shaped organ located in a mass of fat in the abdominal cavity, one on each side of the spine

2: hilum which is a depression on the kidney where the renal vein and the renal artery and nerves are connected to the kidney

3: ureters: narrow tube that emerges from the hilum and brings urine from each kidney to the urinary bladder

4: urinary bladder: is a elastic muscular bag in front of the rectum that stores urine

5: sphincter muscle which is found at the bottom of the bladder and it controls the urine flow into the urethra and out of the body

6: urethra : a duct through which urine passes from the urinary bladder to outside the body

Front

what are the assosicated blood vessels in the kidney

Back

1. 1. renal arteries which brings oxygenated blood containing the nitrogenous waste and excess water from the heart to the kidneys

2. 2: renal vein which brings the deoxugenated blood from which urea nad excess water have been removed, away from the kidneys to the heart

Front

what is the inernal strucutre of teh kdiney

Back

1: the kidney consists of two regions,

the cortex region which is the outer darker red region enclosed by fibrous capsule

and the medulla region which is the inner thicker paler red region consisting of 12- 16 conical structures called pyramids

2: the pyramids contain numerous nephrons and the pyramids project into a funnel like space known as the renal pelvis which is the enlarged part of the ureter inside of the kidney

Front

what is the strcuture of the nephron

Back

1. 1. nephrons are basic functional units of the kdinet, and they are tiny tubules where urine is formed, each kindey consist of 1 milion nephons

2. each nephon constsits of four main parts : bowmans capsule, proximal convulated tubule, loop of henle, distal convoluted tubule

3. several nephrons open into a tube known as the collecting duct.