P1 – Outline the functions of the main cell components.

2. Nuclear membrane – this is a two-layered membrane surrounding the nucleus of a living cell
2. Nuclear membrane – this is a two-layered membrane surrounding the nucleus of a living cell
3. Smooth endoplasmic reticulum – it is important in making and storage of lipids or fats. It has attached ribosomes.
3. Smooth endoplasmic reticulum – it is important in making and storage of lipids or fats. It has attached ribosomes.

1. Mitochondrion – Every cell in the body have rod-shaped or spherical bodies.
1. Mitochondrion – Every cell in the body have rod-shaped or spherical bodies.

4. Cell membrane – known as a plasma membrane. It is a thin semi-permeable membrane that borders around the cytoplasm of a cell.
4. Cell membrane – known as a plasma membrane. It is a thin semi-permeable membrane that borders around the cytoplasm of a cell. 10. Lysosomes – they can be found in all parts of the cell cytoplasm and are small vesicles produces by part of the Golgi apparatus.
10. Lysosomes – they can be found in all parts of the cell cytoplasm and are small vesicles produces by part of the Golgi apparatus.
9. Golgi apparatus – this appears as a chain of flattened, fluid-filled sacs stacked together.
9. Golgi apparatus – this appears as a chain of flattened, fluid-filled sacs stacked together.
8. Rough endoplasmic reticulum – it is covered in tiny black bodies, known as ribosomes.
8. Rough endoplasmic reticulum – it is covered in tiny black bodies, known as ribosomes.
7. Nucleus – this is the biggest structure inside the cell and stands out as a dark shape because it takes up dyes or stains easily.
7. Nucleus – this is the biggest structure inside the cell and stands out as a dark shape because it takes up dyes or stains easily.
6. Cytoplasm – this is a semi-fluid material that is capable of flowing slowly. Many chemical reactions happen here, called metabolism.
6. Cytoplasm – this is a semi-fluid material that is capable of flowing slowly. Many chemical reactions happen here, called metabolism.
5. Ribosomes – It is a cell structure that makes protein. Protein is needed for many cell functions such as repairing damage.
5. Ribosomes – It is a cell structure that makes protein. Protein is needed for many cell functions such as repairing damage.

P2 - Outline the structure of the main tissues of the body.

Tissues are groups of similar cells carrying out specific functions. There are: * Epithelial * Connective * Muscle and * Nervous

Epithelial tissues:
Epithelia are the lining of internal and external surfaces and body cavities, including ducts (tubes or channels) carrying secretions from glands. There are simple and compound types of epithelia.

Simple epithelia:
Simple epithelia may be squamous, cuboidal, columnar or ciliated.
Squamous epithelia cells are very flat, with every nucleus forming a lump in the centre. The word ‘squamous’ means ‘scaly’, referring to the flatness of the cells. They fit together closely, rather that crazy paving. Such delicate thin cells cannot offer such protection and their function is to allow materials to pass through from diffusion and osmosis. They are found in: * Lung alveoli * Blood capillaries

Cuboidal epithelia cells are cube-shaped, with spherical nuclei. They often line ducts and tubes and allow material to pass through in the same way as squamous epithelia. They occur in glandular tissues making secretions. They can be found in: * Kidney tubules * Sweat ducts and * Glands like the thyroid gland and breast tissue
Columnar epithelial cells are much taller, with slightly oval nuclei. They can often be linked with microscopic filaments known as cilia and are then called ciliated epithelia. Cilia move in wave-like motions, beating towards the orifices.

Compound epithelia:
The main function of compound epithelia is to protect deeper structures, and multiple layers of cells hamper the passage of materials. The vagina, mouth, tongue and oesophagus are lined by stratified epithelia made up of squamous, cuboidal or columnar cells, which gradually becomes flattened by pressure from below as they reach the surface.

Connective tissues:

These tissues are distributed widely in the body and lie beneath the epithelial tissues, connecting different parts of the internal structure. There are various types that lie in a background material known as a matrix. The matrix may be liquid as in blood, jelly-like as in areolar tissue, firm as in cartilage, or hard as in bone. The functions of these tissues are to transport materials (as in blood), give support (as in areolar tissue and cartilage), and strengthen and protect (as in bone).

Blood:
Blood consists of straw-coloured plasma (the matrix), in which several types of blood cells are carried. Plasma is mainly water, in which many substances are carried, such as dissolved gases like oxygen and carbon dioxide, nutrients like glucose and amino acids, salts, enzymes and hormones. There is a combination of important proteins.

Cartilage:
This is the smooth, translucent, firm substance that protects bone ends from friction during movement, and forms the key part of the nose and the external ear flaps called pinnae. The matrix is secreted by cartilage cells called chondrocytes and is a secure but flexible glass-like material of chondrin (a protein). The cells become trapped in the matrix and sometimes divide into two or four cells, giving a very characteristic appearance. It does not contain blood vessels and is nourished by diffusion from underlying bone.
Bone:
Bone is a much harder substance than cartilage but it can be worn away by friction. The inflexible matrix has two key components: * Calcium salts, which form around collagen fibres and give bone its hardness and * Collagen fibres, which offers some ability to bend under strain and prevent bone from being too brittle and is therefore likely to fracture.
Bone is designed to bear weight and the limb bones are hollow, like gliders (the strongest mechanical structures). Bone is also used to protect vital weaker tissues such as the brain, lungs and heart. Bones contains marrow in their central hollow and in some bones marrow makes vital blood cells.
Areolar tissue:
This is the most common tissue in the body. It is the sticky, white material, that attaches muscle groups, blood vessels and nerves together, that you see in meat. The matrix is semi-fluid and it contains collagen fibres and elastic fibres secreted by the cells found in this loose connective tissue. Elastic fibres give flexibility to the tissue, which is found around mobile structures.
Adipose tissue:
Adipose is a technical term for fatty tissue and it is a variation of areolar tissue, in which the adipose (fat) cells have multiplied to obscure other cells and fibres. When mature, an adipose cell becomes so loaded with fat that the nucleus is pushed to one side. Adipose tissue is common under the skin and around organs such as the heart, kidneys and parts of the digestive tract. It helps to insulate the body against changes of external temperature and acts like a ‘hydraulic shock absorber’.

Muscle tissue:

Muscle is an excitable tissue because it is capable of responding to stimuli. There are three different types of muscle in the human body: * Striated * Non-striated * Cardiac

Striated muscle:
Most striated muscle (also called voluntary, skeletal or striped muscle) is attached to the bones of the skeleton, even though some facial muscles are attached to skin. Striated muscle makes up the familiar animal meat seen at the butcher’s. This type of muscle will contract when it receives nerve impulses controlled by conscious thought from the central nervous system (CNS).
Non-striated muscle:
Even though, this type of muscle tissue still contains protein filaments, they do not lie in an ordered pattern and therefore do not produce the banding that is characteristics of striated muscle. This type of muscle tends to form sheets and, although still receiving nervous stimulation to effect contraction, this is mot under conscious thought, but supplied by the automatic nervous system. This type of muscle is found around hollow internal organs such as the stomach, intestines, iris of the eye, bladder and uterus; it is not attached to bones.
Cardiac muscle:
This type of muscle is found only in the four chambers (atria and ventricles) of the heart. It is said to be myogenic because it can rhythmically contract without receiving any nervous stimuli, and is different from other muscles.

P3 – Outline the gross structure of the main tissues of the body.

The Renal System: §
The Renal System consists of two kidneys with developing tubes (called the ureters) running down, following abdominal wall to a single pelvic collecting organ, the bladder.
The passage from the bladder to the exterior is via the urethra. A sphincter muscle located just below the bladder controls the flow of urine.
Short renal arteries coming from the main artery of the body, the aorta, supply the kidneys. Renal veins take the blood from the kidneys straight into the vena cava, the main vein of the body.
The Renal System consists of two kidneys with developing tubes (called the ureters) running down, following abdominal wall to a single pelvic collecting organ, the bladder.
The passage from the bladder to the exterior is via the urethra. A sphincter muscle located just below the bladder controls the flow of urine.
Short renal arteries coming from the main artery of the body, the aorta, supply the kidneys. Renal veins take the blood from the kidneys straight into the vena cava, the main vein of the body.

The Nervous System contains the central nervous system (the brain and spinal cord) and the peripheral nervous system, the nerves running to and from the brain (cranial nerves) and spinal cord (spinal nerves).
The Nervous System contains the central nervous system (the brain and spinal cord) and the peripheral nervous system, the nerves running to and from the brain (cranial nerves) and spinal cord (spinal nerves). The Endocrine System is a collection of ductless glands distributed throughout the body. Endocrine glands pass their secretions (known as hormones) directly into the bloodstream so they are always adjacent to blood vessels.
The Endocrine System is a collection of ductless glands distributed throughout the body. Endocrine glands pass their secretions (known as hormones) directly into the bloodstream so they are always adjacent to blood vessels.

The Male Reproduction System has two testes that hang in a skin sac called the scrotum, just outside the abdomen, and are connected by long tubes (each known as vas deferens) to the urethra. The urethra is much longer than that of the female and enclosed in an organ called the penis.
The Male Reproduction System has two testes that hang in a skin sac called the scrotum, just outside the abdomen, and are connected by long tubes (each known as vas deferens) to the urethra. The urethra is much longer than that of the female and enclosed in an organ called the penis.
The Female Reproduction System contains two ovaries, each with an evolving oviduct (or fallopian tube) connecting to the thick-walled uterus (or womb)
The Female Reproduction System contains two ovaries, each with an evolving oviduct (or fallopian tube) connecting to the thick-walled uterus (or womb)

Minute blind-ending lymphatic capillaries lie in tissue spaces between body cells and join to larger lymphatic vessels and ultimately to two lymphatic ducts.
Minute blind-ending lymphatic capillaries lie in tissue spaces between body cells and join to larger lymphatic vessels and ultimately to two lymphatic ducts.

The Musculo-Skeletal System:
The bones of the skeleton and their attached striated muscles form this system. The skeleton forms the structure of the body and it is made up of: * Axial skeleton, in the midline of the body – the skull and vertebral column or spine * Appendicular skeleton, containing the limb bones and their girdles, which attach them to the trunk.
The meeting place of two or more bones is known as a joint or joints may be: * Fixed by fibrous tissue and therefore immoveable; this type occurs between several bones of the skull * Slightly moveable because the bones are joined by a pad of cartilage: this type is found in between the vertebrae and joining the two halves of the pelvic girdle together * Freely moveable with a more complex structure known as synovial joints; examples are found at the shoulder, elbow, knee, hip, fingers and toes.

The immune system:

The immune system is not included as a major system. It is a collection of cells, tissues and proteins that protects the body from invasion by harmful micro-organisms. Below show the main components of the immune system:
White blood cells * Lymphocytes * Granulocytes * monocytes
White blood cells * Lymphocytes * Granulocytes * monocytes

Lymphatic vessels and lymph nodes
Lymphatic vessels and lymph nodes
Spleen
Spleen
Adenoids
Adenoids
Other lymphoid tissue, e.g. in intestines
Other lymphoid tissue, e.g. in intestines
Tonsils
Tonsils
Thymus gland
Thymus gland
Immune System
Immune System

The digestive system is the organ system that breaks down food into small molecules that is absorbed into the bloodstream.
The digestive system is the organ system that breaks down food into small molecules that is absorbed into the bloodstream.
Digestive System:

The human respiratory system consists of a chain of organs that takes in oxygen and takes out carbon dioxide. The main organs are lungs, which carries out this exchange of gases we breathe.
The human respiratory system consists of a chain of organs that takes in oxygen and takes out carbon dioxide. The main organs are lungs, which carries out this exchange of gases we breathe.

The Respiratory System
The Respiratory System

Cardiovascular System:
The cardiovascular system involves two circuits that blood travels through; pulmonary and systemic. Exercise has an impact on these systems, causing the heart to pump blood faster around the body, which in turn allows you to exercise for longer.
The cardiovascular system involves two circuits that blood travels through; pulmonary and systemic. Exercise has an impact on these systems, causing the heart to pump blood faster around the body, which in turn allows you to exercise for longer.