TOPIC 6: HUMAN HEALTH and

PHYSIOLOGY

6.1 DIGESTION

6.1.1: Necessity for digestion

6.1.2: Enzyme action

6.1.3: Various enzymes

6.1.4: Digestive System

6.1.5: Stomach

6.1.5: Small and Large Intestine

6.1.5: Small intestine (x-section)

6.1.7: Villus

6.1.6: Absorption and Assimilation

6.2 THE TRANSPORT SYSTEM

6.2.1: Heart

Left ventricle

Right ventricle

Left Atrium

Right Atrium

Right Atrio-ventricular valve

Left Atrio-ventricular valve

Aorta

Pulmonary artery

Semi-lunar valves

Pulmonary Veins. vena cava

i.vena cava

Coronary artery

6.2.3: Heartbeat

6.2.4: Heartbeat

6.2.5: Blood Vessels

6.2.5: Blood Vessels

6.2.6: Blood

6.2.7: Transported by Blood

6.3: DEFENCE AGAINST INFECTIOUS DISEASE

Pathogen: an organism or virus that causes a disease.

6.3.1: AntibioticsAntibiotics block specific metabolic pathways found in bacteria. Viruses reproduce using the host cell’s metabolic pathways, which are not affected by antibiotics.

6.3.1: Skin and Mucus membranes

Mucous membranes line cavities that are exposed to the external. They are at several places continuous with skin: at the nostrils, the mouth, the lips, the eyelids, the ears, the genital area, and the anus. The sticky, thick fluid secreted by the mucous membranes and glands is termed mucus

SkinThe outer layer of skin is dead and difficult for pathogens to grow on or penetrate.

The best way to prevent disease is to prevent pathogens from entering the body.

Skin forms a physical barrier that prevents most pathogens from entering the body.

Glands in the skin secrete lactic acid and fatty acid, which make the skin surface acidic, preventing bacterial growth.

The outer layer of skin flakes off, which removes bacteria.

Cuts allow pathogens to gain entry to the body.

6.3.4: Phagocytic leucocytes

6.3.5: Antigen and Antibody

An antigen is a substance or molecule that when introduced into the body triggers the production of an antibody by the immune system which will then kill or neutralize the antigen that is recognized as a foreign and potentially harmful invader.

Antibody: A protein produced by B-lymphocytes (specialised type of white blood cell) that binds to a specific antigen

a-f represent only 6 (of the millions) of different lymphocytes

6.3.6: Production of Antibodies

6.3.7: HIV

HIV reduces the number of active lymphocytes and therefore a loss of the ability to produce antibodies

Transmission of HIV

AIDS is a major social problem in all countries, especially in Africa and Asia. It presently infects an estimated 40 million people including men, women and children.

Families & friends suffer grief when a loved one is sick with AIDS.

Families become poorer if the victim becomes unable to work, and individuals with AIDS may be stigmatized by society making it difficult to find employment, housing, and partners.

In countries with high rates of HIV, people may avoid sex or live in fear if sexually active.

The AIDS epidemic is so severe in some African countries that the majority of the workforce has died, thus destroying economies and eroding cultures.

6.4.1: GAS EXCHANGE

6.4.1:

• Ventilation

• Gas exchange

• Cell respiration

6.4.3: Alveoli

6.4.3: Alveoli

6.4.3: Alveoli

6.4.4: Respiratory System

trachea

Left bronchusRight bronchus

bronchioles

alveoli

Right lungLeft lung

diaphragm

6.4.5: Mechanism of Breathing

6.4.5: Mechanism of Breathing

6.4.5: Mechanism of Breathing

6.5: NERVES, HORMONES and HOMEOSTASIS

STATE:The NERVOUS SYSTEM consists of the CENTRAL

NERVOUS SYSTEM (CNS) and PERIPHERAL NERVES, and is

composed of cells called NEURONS that can carry rapid

ELECTRICAL IMPULSES.

6.5.1: Nervous System

6.5.2: Motor Neuron

6.5.3: Nerve impulse

STATE:

Nerve impulses are conducted from receptors to the CNS by sensory neurons, within the CNS by relay neurons, and from the CNS to effectors by motor neurons.

Na+

K+

Na+ K+ pump

Na+ channel K+ channel

6.5.4: Resting and Action Potential

6.5.5: Nerve Impulse

6.5.6: Synaptic Transmission

6.5.7: Endocrine System

The endocrine system consists of glands that release hormones that are transported in the blood and affect target organs.

Homeostasis involves maintaining the internal environment between limits, including blood pH, carbon dioxide concentration, blood glucose concentration, body temperature and water balance.

6.5.8 and 6.5.9: Homeostasis

STATE: homeostasis involves maintaining the internal environment between limits, including blood pH, carbon dioxide concentration, blood glucose concentration, body temperature and water balance.

6.5.10: Control of Body Temperature

6.5.10: Arterioles in skin.

6.5.110: Shivering

6.5.10: Sweating

STATE: The endocrine system consists of glands that release hormones that are transported in the blood.

6.5.11: Control of blood glucose

6.5.10: Islets of Langerhans

6.5.10: Control of Blood Glucose

5.6.11: Type I Diabetes

6.5.11: Type II Diabetes

Distinguish between type I and type II diabetes

Type I diabetes (early or juvenile onset): Auto-immune disease in which the beta-cells pancreatic are destroyed.Unable to produce insulin.Responds well to regular injection of insulin probably manufactured as the genetically engineered humulin.

Type II diabetes (Adult onset):Reduced sensitivity of the liver cells to insulin.Reduced number of receptors on the liver cell membrane

6.6: REPRODUCTION

6.6.1: Male Reproductive System

6.6.1: Female Reproductive System

6.6.2: Menstrual Cycle

FSH: follicle stimulating hormoneLH: lutenising hormone

6.6.3: Menstrual Cycle

8

Start of cycle

FSH levels rise

Lining of uterus (endometrium) breaks down (due to low levels of progesterone and estrogen)

FSH causes follicles to developand estrogen to be secreted by follicle which causes moreFSH to be released

8

Estrogen stimulates repair of the endometrium

Rising estrogen levels cause an LH surge

LH surge causes ovulation

8

8

High LH causes less estrogen to be secreted(an example of negative feedback)

High LH levels also allows progesterone levels to rise

After ovulation follicle develops into the corpus luteum which secretes progesterone which maintain the endometrium

8

High levels of progesterone inhibit FSH and LH secretion (negative feedback)

8

If no embryo is formed the corpus luteum breaks down then progesterone and estrogen levels fall and endometrium will break down

Low levels of progesterone and estrogen allow levels of FSH to rise

6.6.4: Testosterone

Testosterone: Prenatal development of male genitalia

Development of secondary sexual characteristics

Maintenance of sex drive

6.6.5: IVF

6.6.6: Ethical Issues with IVF

• FOR:

• AGAINST