BIOL121 – Anatomy and Tissue Structure
- Basic systems and major organs
Levels of Organisation
1) Chemical Level: atoms, smallest unions of matter in a chemical reaction and
molecules e.g: carbon, hydrogen, oxygen and nitrogen or even DNA and glucose.
2) Cellular Level: molecules combine to form cells
3) Tissue Level: group of cells and materials surrounding that work together to perform
a function: Epithelial, connective, muscular and nervous.
4) Organ level: different types of tissue join together to form an organ with specific
functions: Heart, liver, bones and stomach.
5) System level: Related organs which join to perform a common function: Digestive
system. Organs can be a part of multiple systems
6) Organisational level: Organism is any living individual: Human
, - The 11 systems of the body
1) Integumentary system
COMPONENTS: Skin (structures derived from it) hair, skin nails, sweat glands and oil glands.
FUNCTIONS: Protection, regulate body temperature, eliminates waste, helps make vitamin
D, detects sensations and stores fat (insulation)
2) Skeletal system
COMPONENTS: Bones, joints and cartilage
FUNCTIONS: Support and protects the body, surface area for muscle attachment, body
movement, houses cells that produce blood cells, stores minerals and fats (lipids)
3) Muscular system
COMPONENTS: Skeletal muscle tissue attached to bone by tendons
FUNCTIONS: Body movements, maintains posture, produces heat
4) Cardiovascular system
COMPONENTS: Blood, heart and blood vessels
FUNCTION: Transportation of substance, regulate acid-base balance and temp + water
content of fluids, help defend against disease and repair damaged blood vessels.
5) Lymphatic and Immune system
COMPONENTS: Lymphatic fluid and vessels, spleen, thymus, lymph nodes and tonsils. Cells
that carry out immune response (T/B lymph oocytes)
FUNCTIONS: Returns proteins/fluid to blood carries lipids from gastrointestinal tract to
blood, protects against disease.
6) Endocrine System
COMPONENTS: Hormone-producing gland (pineal gland, hypothalamus, pituitary gland,
thymus, thyroid gland, parathyroid gland, adrenal gland, pancreas, ovaries and testes) and
hormone producing cells in other organs.
,FUNCTIONS: Regulates body activities by releasing hormones (chemical messengers
transported in blood from endocrine gland or tissue to target organ)
7) Nervous System
COMPONENTS: Brain, spinal cord, nerves and special senses (eyes, ears)
FUNCTIONS: Generates action potentials, regulates activities, detects changes in body’s
internal and external environments, detects stimuli and responds by muscles contractions or
glandular secretion.
8) Respiratory system
COMPNENTS: Lungs, air passageways (pharynx, larynx, trachea and bronchial tubes).
FUNCTIONS: Transfer oxygen into blood and CO2 from blood to exhaled air regulates acid-
base balance of body fluids, air flowing out of lungs over vocal cords produces sound.
9) Digestive System
COMPONETS: Organs of the gastrointestinal tract (mouth, pharynx, oesophagus, stomach,
small and large intestines) and accessory organs (salivary glands, gall bladder, liver and
pancreas).
FUNCTIONS: Physical and chemical breakdown of food, absorbs nutrients and eliminates
solid waste.
10) Urinary system
COMPONENTS: Kidneys, ureters, urinary bladder and urethra.
FUNCTIONS: Produces, stores and eliminates urine and waste, regulates volume and
chemical composition of blood, helps maintain the acid-base balance of body fluids, helps
regulate production of red blood cells.
11) Reproductive System
COMPONENTS: Female: ovaries, uterus, fallopian tubes and vagina. Male: testes,
epididymis, vas deferens and penis.
FUNCTIONS: gamete production, hormone release and body changes during puberty.
, - Tissue types and structures
A tissue is a group of similar cells that usually have common embryonic organs and functions
together to perform specialised functions.
Origins of body tissues
Cell junctions – Joining cells in tissues together, contact points between plasma membranes
of tissue cells. How cells are held together to form tissues.
a) Tight junction
Web like strands of transmembrane
proteins, fuse together outer surfaces of
adjacent plasma membranes and seals
off passage between cells. Prevents
organs leaking.
Featured in:
epithelia tissues in
stomach,
intestines, urinary
bladder.