Protection of the body and continuation of the species

Question 1

Protection against the external environment

Answer 1

• Skin (2 layers of skin dermis & epidermis) = physical barrier = stops microbes, checmials & dehydration.
• epidermis = superficial & composed of several cells that grow towards the deepest level of the skin. It provides a barrier between a moist internal environment and a dry external environment
• skin = regulation of body temperatures
• dermis = sweat glands, little canals and ducts; sweating is essential for heat loss. Sensory nerves to deal with pain, temperature and touch

Question 2

Non-specific defence mechanisms

Answer 2

• sticky mucus secreted by mucus membranes = trap microbes & other foreign materials
• body fluids contain antimicrobial substances, e.g. gastric juices (hydrochloric acid) = kill microbes
• if microbes enter the body to infect tissues. Other defence systems activated, e.g. inflammatory responses

Question 3

Specific Defence Mechanisms

Answer 3

• Antigens, including pollen from flowers and plants
• Microbes, e.g. bacteria and abnormal cells, e.g. from tumour/transplanted tissues
• individuals build up immunity to millions of antigens. `
• Abnormal immune response to an antigen that poses a threat to the body

Question 4

Movement

Answer 4

• rigid body frameworks and movement take place in joints between 2 or more bones
• Skeleton Muscles control the voluntary nervous system = maintain posture and balance
• tendons move bones
• Movable joints supported by outer sleeves of fibrous tissues = ligament
• learned movement & balance often become subconsciously controlled e.g. riding a bike

Question 5

Survival of the species

Answer 5

• depends on how good the reproduction
• transmit genetic material to children
• fusion of male and female sex cells = sexual reproduction
• fertilisation showing spermatozoon penetrating an ovum
• 1900s ionised radiation = X-rays, higher scans = ultrasound scans, MRI (magnetic resonance imaging), CT scans (computer tomography)