Male reproductive system Sperm duct

Sperm are produced in the seminiferous tubules. Sperm production is stimulated by testosterone, released by the interstitial cells. Sperm are stimulated to swim by seminal fluid, released by the prostate gland and seminal vesicle. This aids fertilisation.

Female reproductive system During the menstrual cycle, the ovary produces two hormones. 1.Oestrogen, secreted by the Graafian follicle. 2.Progesterone, secreted by the corpus luteum.

Oxytocin (from pituitary) stimulates the rhythmical contractions of the muscles of the uterus wall known as labour. Prolactin (from pituitary) stimulates the mammary glands to produce milk after birth. Oestrogen (from placenta) – maintains endometrium during pregnancy, but levels rise towards end, making the muscular walls of uterus more susceptible to the action of oxytocin, so stimulating contraction of the uterus. Progesterone (from placenta) – maintains endometrium, inhibits release of oxytocin and prolactin, and causes proliferation of milk-secreting tissue in mammary glands. During pregnancy and childbirth

Colostrum is a fluid produced by the breasts for a few days after birth. Normal breast milk is produced after that. New mothers are advised to breast feed their babies for at least the first few days because colostrum is a very rich source of human antibodies.

Transport. The heart pumps blood round the body in blood vessels. The order is ; heart arteries arterioles capillaries venules veins

There is a large pressure drop in capillaries. Materials pass out of the blood and into the tissue fluid that surrounds the cells – except red blood cells and proteins The composition of the blood changes in the following ways as it passes through capillaries; Oxygen decreases Concentration of glucose decreases Concentration of carbon dioxide increases

Red blood cells Capillaries are very narrow. In order squeeze along them, red blood cells have a very small size and are flexible. To absorb oxygen, red blood cells contain a pigment called haemoglobin.

Glomerulus (network of capillaries) Bowman’s capsule Proximal convoluted tubule Distal convoluted tubule Collecting duct (leading to the pelvis of the kidney) loop of Henle arteriole Kidney Nephron venule (Blood enters) (blood leaves)

The nephron produces urine. Urine consists of urea, excess salts and excess water. It does this by carrying out ultrafiltration, followed by reabsorption of useful materials back into the blood. Many substances excreted in the urine become more concentrated as they move towards the end of the nephron, due to water being reabsorbed.

Temperature regulation The hypothalamus is the temperature monitoring centre in the brain. Regulation can be voluntary or involuntary. Voluntary regulation Involuntary regulation Changing clothes, Drinking hot or cold liquids, Taking shelter Exercising Sweating Shivering Changes in metabolic rate Vasodilation Vasoconstriction Contraction of hair erector muscles

Hypothermia – the lowering of core body temperature to below 35 o C Infants and the elderly are more likely to suffer from hypothermia than any other age group because; Infants Have a large surface area to volume ratio, therefore lose heat more quickly. They can’t carry out voluntary responses to warm themselves up. Their temperature regulatory mechanisms are not fully developed.

Elderly Are less mobile. May have a poor diet. Can’t afford to heat their homes. Have a low metabolic rate. Their temperature regulatory mechanisms have deteriorated.

General Correctly use the terms validity and reliability, -- never say “to make it fair” Never use the word “amount”, use the proper term e.g. volume, mass, etc. Graphs Draw the right type of graph i.e. line or bar graph. Don’t miss out the origin. Make sure your scale will give a graph which covers more than half of the graph paper, gives equal divisions, and is labelled fully – including units. The top of the scale should be equal to, or above your last value Accurately plot the points and join with a ruler. Only join points given, don’t extend in either direction. Don’t draw line of best fit unless specifically required.