1. HUMAN PHYSIOLOGY RHODA OLADAPO IB BIOLOGY 2 SL.

2. SUB-TOPICS DIGESTION THE BLOOD SYSTEM DEFENCE AGAINST INFECTIOUS DISEASES GAS EXCHANGE NEURONES & SYNAPSES REPRODUCTION

3. DIGESTION This is the break down of large molecules.(usually food. Duhh!) into the simplest and smallest molecular forms by chemical reactions. Reasons for Digestion For the conversion of large food substances into smaller molecules to pass through the cells in the wall of the gut Break down of proteins and other macromolecules so that the human bod can obtain all the subunits that it needs to build up its own macromolecules.

4. Enzymes are used to speed up the process of digestion. These enzymes are all made in glands and secreted into the gut, where they mix with the food. ENZYMES IN DIGESTION Large Molecule EnzymeSmall molecule StarchAmylaseMaltose ProteinProteaseAmino acids LipidslipaseFatty acids + glycerol EnzymeSecreting glandsRegion enzyme works pH of region where enzyme works Amylase Salivary glands Pancreas Mouth Small intestine 6.0 - 7.0 7.0 – 8.3 Protease Stomach wall Pancreas Stomach Small intestine 1.0 - 3.5 7.0 - 8.3 Lipase PancreasSmall Intestine7.0 - 8.3

5. STRUCTURE OF THE DIGESTIVE SYSTEM Side note: The gall bladder is connected to the liver. The liver is connected to the stomach. The purpose f the liver is to make bile which is a digestive fluid stored in the gall bladder. The part of the human body used for digestion can be described as a tube. The wall of the tube is made of living tissues. TissueFunction Muscle fibersTo push the food along Secretory cellsTo produce mucus for lubrication and enzymes for digestion. Epithelial cellsForms the inner lining and absorbs digested food. Tissues in the digestive system and their functions

6. STRUCTURE & FUNCTION OF THE STOMACH The wall of the stomach is called a glandular. It secretes mucus, hydrochloric acid and protease Hydrochloric acids kills the bacteria in the food we swallow Protease secreted in the stomach is called pepsin which begins the process of denaturing proteins by breaking up polypeptides into shorter chains of amino acids. The elasticity of the stomach allows for the swallowing of large meals. The wall of the stomach is muscular which contracts to squeeze, mix and break food into smaller pieces. CHURNING

7. STRUCTURE & FUNCTION OF THE SMALL INTESTINE Longitudinal region Circular Regional

8. DIFFERENCE BETWEEN ABSORPTION & ASSIMILATION Absorption: is the process of taking in substances. It happens in the small intestine. Structures called villi are adapted to carry out this process. Assimilation: is the process when substances derived from food becomes part of the structure of the body. STRUCTURE OF A VILLUS

9. THE TRANSPORT SYSTEM

10. MAIN TRANSPORT SYSTEM IN HUMANS CONSISTS OF: Blood The heart to pump it Blood vessels through which it is pumped. blood vessels arteries CapillariesVeins Pulmonary Circulation: To and from lung Systematic circulation: To and from all other organs including the heart itself.

11. STRUCTURE OF THE HEART

12. CONTROL OF THE HEART BEAT Contraction is myogenic ( the muscle in the heart stimulates its contraction ) The region of the heart that sets the overall pace of contraction is the PACEMAKER ( a small group of muscle cells in the wall of the right atrium) Branches of two nerves are connected to the pace maker which brings signals from a region in the medulla of the brain Impulses from one of the nerves causes the pacemaker to increase the rate while the other nerve causes it to decrease The pacemaker also responds to adrenalin causing an increase in heart rate.

13. The Structure of the Blood Plasma: A fluid between blood cells. Platelets: Cells that circulates in the blood which clots to keep us from bleeding Erythrocytes: Red blood cells Leukocytes: White blood cells Phagocytes: Cells that engulf foreign materials

14. DEFENCE AGAINST INFECTIOUS DISEASE The skin and mucous membrane form a primary defense against pathogens that cause infectious diseases Cuts in the skin are sealed by blood clotting Clotting factors are released from platelets. Ingestion of pathogens by phagocytic white blood cells gives non-specific immunity to diseases

15. PRODUCTION OF ANTIBODIES Antibodies are produced by lymphocytes n response to specific antigens

16. WHY ANTIBIOTICS DO NOT WORK ON VIRUSES Viruses lack a metabolism and therefore cannot be treated with antibiotics Some bacteria are resistance to antibiotics because they have multiple resistance.

17. GAS EXCHANGE

18. Ventilation maintains concentration gradient of Co2 and O2 between air in alveoli and blood flowing in adjacent capillaries. Cells in the lungs Type I pneumocytes: Are extremely thin alveolar cells that are adapted to carry out gas exchange Type II Pneumocytes: Secretes a solution containing surfactant that creates a moist surface nside the alveoli to prevent the sides of the alveolus adhering to each other by surface tension.

19. PROCESS IN WHICH VENTILATION OCCURS Air is carried to the lungs in the trachea and bronchi and then to the alveoli in bronchioles Muscle contractions cause the pressure changes Inside the thorax that force air in and out of the lungs to ventilate them. Different muscles are required for inspiration and expiration.

20. NEURONS AND SYNAPSES

21. Neurons transmits electrical impulses A nerve impulse is only initiated if the threshold potential is reached

22. Neurons pump sodium nd potassium ions across ther membranes to generate a resting potential. An action potential consists of depolarization and repolarization of the neurons. Nerve impulses are action potentials propagated along the axons of neurones. Propagation of nerve impulses is a result of all local currents that cause each successive part of the axon to reach the threshold potential.

23. Synapses are junctions between neurons and between neurones and receptors When presynaptic neurones are depolarized, they release a neurotransmitter into the synapse

24. Hormones, homeostasis and reproduction

25. Insulin and glucagon are secreted by beta and alpha cells of the pancreas respectively Leptin is secreted by cells in adipose tissue and acts on the hypothalamus of the brain to inhibit appetite Melatonin is secreted by pineal glands to secrete circadian rhythms (sleeping). Thyroxin is secreted by the thyroid gland to regulate the metabolic rate and to help control body temperature.

26. Human reproduction involves the fusion of a sperm from a male and an egg from a female The hormone present in the male reproductive system is the testosterone while estrogen and progesterone are present in females. At puberty, the production of testosterone increases while estrogen and progesterone during pregnancy or menstruation.

27. SPERMATOGENESIS AND OOGENESIS

28. IVF( In-vitro fertilization)

29. FEMALE REPRODUCTIVE SYSTEM AND THE MENSTRUAL CYCLE a part of the female system known as the hypothalamus is the regulatory center of the menstrual cycle. FSH and LH are the hormones involved in this process and the target tissues for these hormones are the ovaries.

30. MALE REPRODUCTIVE SYSTEM