How your body works

What it does?

The main functions of the musculoskeletal system are to protect the vital organs, provide structural support and allow the body to move. In addition, muscles generate heat and bones store minerals such as calcium and phosphorous as well as producing red blood cells, platelets and white blood cells.

Includes:

• Bones
• Cartilage
• Joints
• Muscles
• Tendons
• Ligaments
• Intervertebral discs

What it does?

The cardiovascular system circulates blood around the body delivering oxygen and nutrients to organs and cells and carrying carbon dioxide and waste products away. It also protects the body from infection and blood loss, and helps maintain a constant temperature and fluid balance.

Includes:

• Heart
• Blood
• Arteries
• Veins
• Capillaries

What it does?

The nervous system is the communication pathway for the body, sending messages between different parts via electrical and chemical processes. It responds to changes both outside and inside the body and coordinates voluntary movements, receives external stimuli, including hearing, touch and sight as well as controlling heart rate, digestion, breathing, salivation, perspiration, pupil diameter, urination and sexual arousal.

Includes:

• Brain
• Spinal Cord
• Retina and optic nerve
• Peripheral nerves

What it does?

The respiratory system delivers oxygen to the body and removes carbon dioxide through breathing. The oxygenated blood goes to the heart where it is pumped to other parts of the body and the carbon dioxide is exhaled from the lungs.

Includes:

• Mouth
• Nose and nasal cavity
• Pharynx
• Larynx
• Trachea
• Lungs
• Bronchi
• Bronchioles
• Alveoli
• Diaphragm

What it does?

The digestive system mechanically and chemically breaks down food to extract energy and nutrients for the body. Digestion starts in the mouth, continues in the stomach and finishes in the small intestine with the release of enzymes from the pancreas. Absorption of nutrients also takes place in the small intestine and then waste left over from the digestive process is transferred along the large intestine until eliminated from the body by the rectum and anus.

Includes:

• Mouth
• Pharynx
• Oesophagus
• Stomach
• Small intestine
• Pancreas
• Large intestine
• Rectum
• Anus

What it does?

The urinary system works with other organs (lungs, intestines and skin) to remove waste from the body and to keep the chemicals and water in the body balanced. The kidneys remove urea from the blood which, together with water and other waste substances, forms urine. The urine travels down two thin tubes called ureters to the bladder where it is stored until it passes out of the body via the urethra.

Includes:

• Kidneys
• Ureters
• Bladder
• Urethra
• Penis

What it does?

The integumentary system is primarily made up of the largest organ in the body, the skin. The skin protects the body from attack by foreign organisms and prevents the escape of bodily fluids; it helps regulate the body’s temperature, provides sensory reception, synthesises vitamin D and hormones, and can absorb substances.

Includes:

• Skin
• Hair
• Nails
• Exocrine glands (includes sweat, salivary, mammary, ceruminous, lacrimal, sebaceous, and mucous)

What it does?

The endocrine system is a collection of glands that send messages to target organs by releasing hormones straight into the bloodstream. These hormones, which include thyroxine, adrenalin, cortisol and insulin, regulate mood, sleep, stress response, growth and development, metabolism, digestion, sexual function and reproductive processes. The endocrine system is regulated by feedback in much the same way that a thermostat regulates the temperature in a room.

Includes:

• Pineal gland
• Hypothalamus gland
• Pituitary gland
• Thyroid gland
• Parathyroid gland
• Adrenal glands
• Pancreas
• Reproductive glands

What it does?

The reproductive system, which is actually part of the endocrine system, is a collection of internal and external organs that work together for the purpose of producing offspring. In women, the ovaries produce and release progesterone and oestrogen, promote the healthy development of female sex characteristics during puberty and ensure fertility. Oestrogen also prevents abnormal blood clotting and keeps bones strong. In men, the testes produce testosterone which encourages sperm production and leads to secondary sexual characteristics.

Includes (Male):

• Testicles
• Epididymis
• Vas deferens
• Seminal vesicle
• Urethra
• Prostate gland
• Penis
• Scrotum

Includes (Female):

• Ovaries
• Fallopian tube
• Uterus
• Cervix
• Vagina
• Labia
• Clitoris
• Bartholin’s Glands

What it does?

The liver has many functions in the body. These include manufacturing bile which is stored in the gall bladder, breaking down food and turning it into energy to be released when needed, combating infections, storing essential vitamins, blood clotting, tissue repair plus breakdown and regulation of hormones, drugs and toxins. The liver has two major detoxification pathways designed to convert fat-soluble chemicals into water soluble chemicals so that they may then be easily excreted from the body via bile and urine.

Includes:

• Liver
• Gall bladder
• Bile ducts

What it does?

The immune system is our defence mechanism and defends the body from pathogens, including bacteria and viruses. It’s made up of white blood cells, proteins, and other tissues, including the lymphatic system. As well as participating in our defence against infection, the lymphatic system drains excess fluid from the body tissues and removes debris from that fluid. It also absorbs fats and fatty acids from the bowel and transports them into the bloodstream.

Includes:

• Lymph ducts
• Lymph vessels
• Lymph nodes
• Bone marrow
• Thymus
• Spleen
• Appendix
• Tonsils
• Adenoids
• Peyer’s patches