Unit 6: Anatomy & Physiology

Muscular System

Action of the Muscles

Muscular Tissue

There are three types of muscular tissue; Voluntary or Striped Muscle; Involuntary or Unstriped Muscle and Cardiac Muscle.

• Voluntary or Striped Muscle

This muscle is under voluntary conscious control of the brain. It is found attached to the bones of the skeleton and this type of muscle is used in movement.  These muscles are capable of doing a great deal of work, but will tire easily.

• Involuntary or Unstriped Muscle

This muscle is not under the conscious control of the brain.  It is found in the wall of the alimentary canal, of blood vessels and in the uterus and bladder.  These muscles cannot product strong contractions and are therefore not used for movement.  They do not tire easily and are used for continuous work.

• Cardiac Muscle

These muscles are only found in the wall of the heart.  They never tire and can produce the strong contractions which are required to pump the blood around the body.  This is a very specialised muscle that requires large supplies of oxygen.

Muscles of the Head & Neck

Lymphatic System

The lymphatic system and circulatory system together form the vascular system.

The lymphatic system is part of the body’s immune system, which provides defence against disease causing organisms.  It consists of lymphatic capillaries, vessels, nodes and ducts.  The capillaries and vessels form a network around the body which acts as tunnels for the transportation of lymph fluid, in the same way that blood vessels provide a network for the transport of blood.

When the blood circulates through the capillaries, fluid passes through the thin walls which in turn passes into the tissues thus covering the various individual cells with the required nutrients.

The cells’ waste products are absorbed by acid, most of which is collected by the vessels forming the lymphatic system.  These vessels contain lymph which is a straw coloured fluid similar to blood plasma.

Lymph straw coloured fluid that carries more waste than nutrients.  It contains absorbed fats, urea, glucose, sugar, salts, lymphocytes and some plasma protein. 

Lymphatic Capillaries

Lymphatic capillaries appear in tissue spaces which, in close relation with the blood, come together to form lymph vessels, these vessels run in both subcutaneous issue and the deeper tissues of the body.

Are one cell thick, hair-like structures which combine to form lymphatic vessels they transport lymph from the tissues.    They are bind-ended tubes, situated between cells and are found throughout the body.  The walls of lymphatic capillaries are structured in such a way that tissue fluid can pass into them but not out of them.

Lymphatic Vessels

Are larger and thicker than capillaries, and contain valves which prevent backflow of lymph.  They transport lymph through one or more lymphatic nodes.  Lymph travels around the body in one direction only, towards the heart.  It is carried in vessels that begin as lymphatic capillaries.  These capillaries join up and become wider tubes, known as lymphatic vessels.  The lymph vessels generally run parallel to the veins.  These vessels are similar to veins as they contain valves, although they generally have thinner walls.  The lymph flows around the body through these lymph vessels and passes through a number of lymph nodes to be filtered.  

The lymphatic system does not have pump like the heart, but like veins relies on the movement of the body and the contraction of the skeletal muscles.  The squeezing action of the muscles forces the lymph along its vessels.  Involuntary actions such as breathing and the heartbeat also help the movement of lymph through the vessels

Lymph Nodes

Lymph nodes occur at intervals in the lymphatic system.  These are small oval items which are the place where lymphocytes are formed, and they further act as filters.

Lymph nodes have a fibrous outer capsule containing lymphoid tissue, they vary in size from a pin head to an almond and filter lymph to remove bacteria so can become swollen and tender if infection is present.  They also produce some antibodies.  Lymph enters the node through the afferent lymphatic vessels and leaves the node via the efferent lymphatic vessels.  As many as five afferent lymph vessels may enter a node while only one or two efferent vessels carry lymph away from it.  Trabeculae divide the node into sections, provide support and enable blood vessels to enter into the node.

There are approximately 600 bean-shaped lymph nodes scattered throughout the body.  They lie mainly in groups around the groin, breast, arm pits and round the major blood vessels of the abdomen and chest. 

Lymph is transported by pressure on skeletal muscles and small valves in said vessels.  It enters the venous system slowly as the Lymph is not pumped by any muscle like the heart.  The flow of Lymph can be stimulated by pressures from massage.

Important groups of lymph nodes in the head are:-

• Occipital
• Submandibular
• Deep cervical
• Superficial cervical glands
• Anterior auricular
• Posterior auricular

Important groups of lymph nodes in the rest of the body include the:-

• Axillary
• Abdominal
• Inguinal
• Popliteal
• Supratrochlear

Lymphatic Ducts

The lymphatic ducts are known as the thoracic duct and the right lymphatic duct.  The larger thoracic duct is about 45 cm long, has valves and is located at the back of the abdomen.  The smaller right lymphatic duct is about 1 cm long and is formed by the joining of the vessels from the head, thoracic and right limb.  These collect lymph and return it to the bloodstream.

The thoracic duct is the main collecting duct of the lymphatic system and receives lymph from vessels in the abdomen and lower limbs and empties into the left subclavian vein.  The right lymphatic duct empties into the right subclavian vein.

Functions of the lymphatic system:

The circulatory system works to keep the capillaries supplied with the required amount of blood for its needs.

1. Returns fluid and proteins from tissues to the blood.
2. Transports lymphocytes from lymph nodes to the circulation
3. Carries fatty foods from the intestines to the circulation
4. Filters out and destroys micro-organisms to prevent the spread of  Infection
5. Produces antibodies to prevent subsequent infection

The Spleen

The spleen consists of lymphatic tissue and is part of the lymphatic system.  It is oval in shape and weighs approximately 200g.  The spleen is situated in the left side of the abdomen, beneath the diaphragm and behind the stomach.  The normal adult spleen is about the size of a large apple.

Functions of the spleen:

• The spleen acts as a reservoir for blood. if blood is needed elsewhere in the body because of a haemorrhage etc, it can be diverted.
• Lymphocytes are produced here so the spleen is an important part of the immune system.  If the spleen has to be removed, resistance to disease may be slightly lowered.
• The spleen has good blood supply.  Old worn-out red blood cells are filtered from the blood and destroyed after 12 day life.
• The spleen can be easily damaged by trauma.  If this happens a haemorrhage can occur, the damaged spleen must be removed quickly.  The body is still able survive without it.

The Skeletal System

The skeletal system consists of the bones and joints of the body.  There are 206 bones in the body.  The skeleton helps give the body its shape and supports the weight of all the other tissues.  It provides attachment for muscles and tendons and helps to protect vital organs from injury (i.e.  skull protects brain, ribs protect heart and lungs).

Red and white blood cells plus platelets are produced within the red bone marrow of the bone.  Bones also store minerals such as calcium and phosphorus which help strength the bones.  The bones will release these minerals into the blood stream if needed elsewhere in the body.

Ligaments are made up of bands of strong fibrous connective tissue which are silvery in appearance; they help prevent dislocation of the joints by holding the bones and muscle together.  The ligaments stretch to allow movement.

Joints are where one or more bones meet up with another bone.

• Fibrous joints are fixed joints that are unable to move, i.e. joints between the skull bone.

• Cartilaginous joints move slightly but only have limited movement, i.e. the joints between the bones of the vertebral column and the intervertebral discs.

• Synovial joints are freely moveable joint, i.e. the joint of the knee of elbow. 

The skeletal system has several important functions which are:

• Gives the body support, movement capability and height
• Protects delicate areas with none such as the skull and rib cage
• Is responsible for red blood cell formation in marrow cavities and calcium storage
• It maintains posture by using the anti-gravity muscles
• Transmits sound waves
• It allows for attachment of muscles
• Levers to push against the ground to allow walking

There are four different types of bone:

• Long
• Short
• Flat
• Irregular

The bones are attached to each other via joints in several ways which allows a variety of movement

The three main joints are:

• Fixed, fibrous joints such as the skull
• Cartilaginous, slightly movable joints, such as pelvis
• Senoia, freely movable joints such as ball & socket, hinge, pivot and gliding joints

The four main type of joint movement are:-

• Gliding – feet and hands – closely articulating bones
• Angular- flexion, extension, abduction adduction
• Rotation – allows the bone to pivot on its own axis
• Circumfusion – the bone follows an imaginary cone shaped path as it moves

The Skin

The skin is a large organ and the most active and forms a protective, waterproof covering over the entire surface of the body and weighs approximately one ninth of our total body weight. It is thinnest on the eyelids and thickest on the soles of the feet. The skin is continually shedding and renewing itself. We are able to feel sensations such as pain or heat because of sensors in the skin which transmit messages to the brain and outer skin plays a major role in maintaining body temperature and in protecting the body from harm

The skin varies in colour due to age, race inherited factors and external factors such as climate. The skin can vary in thickness depending upon where it is on the body, i.e., eye and lip skin is very thin whereas hand and foot skin is thicker. The thickness of the skin can affects it’s colour, for example thin skin will look more pink as the blood in subcutaneous tissue will show through, whereas thicker skin, such as on the soles of the feet, tends to look yellow.
There are also medical reasons for skin colour to change such as with rashes where the skin will be more red, heart or lung conditions which will turn the skin blue, or jaundice which will yellow the skin.

With age and sun damage the skin will lose some of its elasticity due to lack of collagen, at which time wrinkles will appear. The skin secretes an oily substance known as ‘Sebum’ which will help to maintain the skin’s suppleness, although there are no sebaceous glands on the palms of the hand or soles of the feet.

The skin also secretes sweat which is usually the result of temperature changes – this is known as insensible perspiration, but can be due to fear or nervousness which is known as sensible perspiration. This last form is produced by apocrine sweat glands.

The skin is made up of three layers called:
• Epidermis
• Dermis
• Subcutaneous

Epidermis

The epidermis is the upper portion of the skin and consists of five layers:
• Horny layer (stratum corneum)
This is the top layer of the epidermis and consists of flat, overlapping, keratinised cells. Keratin is a protein responsible for the hardening process (keratinisation) that cells undergo when they change from living cells with a nucleus to dead cells without a nucleus. Cells that have undergone keratinisation are therefore dead. The keratinised cells help to prevent bacteria entering through the skin and protect the body from minor injury. Cells of the horny layer are continually being rubbed off the body by friction and are replaced by cells from the layers beneath. The shedding of dead skin cells is known as desquamation.
• Clear layer (stratum lucidum)
This is found below the horny layer and consists of dead keratinized cells without a nucleus. The cells are transparent, which allows the passage of sunlight into the deeper layers. This layer is only found on the fingertips, the palms of the hands and the soles of the feet.
• Granular layer (stratum granulosum)
Contains cells that have a granular appearance. As the cells die they fill with tiny granules called kerathohyalin and so keratinisation begins to take place. This layer consists of living and dead cells.
• Prickle cell layer (stratum spinosum)
In this layer the cells are living. The cells interlock by arm-like fine threads, which give the cells a prickly appearance. Pigment granules called melanin may be found here.
• Basal layer (stratum germinativum)
This is the deepest layer in the epidermis and is in contact with the dermis which is directly beneath it. These cells are living and contain a nucleus and divide (mitosis) to make new skin cells. As the new cells are produced they push older cells above them towards the surface of the skin, until they finally reach the horny layer. It takes 3 – 6 weeks for the skin cells to be pushed up from the basal layer to the horny layer.

Dermis

The dermis lies below the epidermis, and connects with the basal layer and is often described as the “True skin”. It consists of two layers:

• Papillary layer
This is the upper section and contains small tubes called capillaries, which carry blood and lymph. It also has nerve endings. This layer provides nutrients for living layers of epidermis.

• Reticular layer
This contains many connective tissue fibres. Collagen gives the skin strength and elastin gives the skin its elasticity. Wavy bands of tough collagen fibres restrict the extent to which the skin can be stretched, and elastic fibres return the skin back to shape after it has been stretched.
The dermis also contains nerves, hair follicles, sebaceous glands, sweat glands and arrector pili. These are known as appendages.

•Subcutaneous layer
The subcutaneous layer is situated below the dermis. It consists of adipose tissue (fat) and areolar tissue. The adipose tissue helps to protect the body against injury and acts as an insulating layer against heat loss, helping to keep the body warm. The areolar tissue contains elastic fibres, making this layer elastic and flexible. Muscle is situated below the subcutaneous layer and is attached to bone.

•Adipose Tissue
This is a loose connective tissue whose specific purpose is to store fat. Adipose tissue is found under the skin and around organs, it acts as a food reserve. As it is also a poor conductor of heat it assists in maintaining body temperature by preventing heat loss.
It is thought that massage affects the adipose tissue as it softens the hard fat under the skin and helps to disperse it.
The distribution of the fat layer under the skin varies according to sex, age and lifestyle. Women tend to have a thicker layer of adipose tissue than men, giving the female form a softer outline. Following the menopause, women tend to put on weight in the more masculine areas such as the waist and abdomen rather than the hips and thighs.

Fat Distribution

Appendages of the skin

• Hair – hairs are dead structures that are made of a hardened protein called keratin and grow out from follicles. Most of the body is covered with hairs, with the exception of the palms of the ands and the soles of the feet. They help to keep the body warm and are also a form of protection. The eyelashes prevent substances from entering the eyes, and the hairs that line the nose and ears help to trap dust and bacteria. The hair is made up of three layers:
o Cuticle – which is the outer part of the hair and consist of a single layer of scale like cells. These cells overlap rather like tiles on a roof. No pigment is contained within this layer.
o Cortex – lies inside the cuticle and forms the bulk of the hair. It contains melanin, which determines the colour of the hair. The cortex helps to give strength to the hair.
o Medulla – is the inner part of the hair and is not always present. Air sacs in the medulla determine the colour tone and sheen of the hair because of the reflection on light.

• Hair follicles – is an indentation of the epidermis with the walls of the follicle being formed from a continuation of the cellular layer of the skins surface. They are in the form of deep pits that extend into the dermis.

• Arrector pili muscle – are small muscles attached to the hair follicles. When we are cold or frightened the contraction of these muscles cause the hairs to stand on end. This results in the appearance of goose bumps. Air is trapped between the skin and hair and is warmed by body heat.

• Sweat Glands – Sweat consists of 99.4 per cent water, 0.4 per cent toxins and 0.2 per cent salts. There are two type of sweat glands in the body:
o Eccrine glands – which excrete sweat and are found all over the body. The sweat duct opens directly on to the surface of the skin through an opening called a pore. Sweat is a mixture of water, salt and toxins. Black skins contain larger and more numerous sweat glands that white skins.
o Apocrine glands – these are found in the armpits, around the nipples and in the groin area. They secrete a milky substance. These glands are larger than eccrine glands are attached to the hair follicle; they are controlled by hormones and become active at puberty. Body odour is caused by the breaking down of the apocrine sweat by bacteria. Substances called pheromones are present in this milky substance, the smell is thought to play a part in sexual attraction between individuals and the recognition of mothers by their babies.

• Sebaceous glands – are small, sac-like structures which produce a substance called Sebum. These glands are found all over the body except for the soles of the feet and the palms or hand. They are more numerous on the scalp and areas of the face, such as the nose, forehead and chin. The glands are attached to the upper part of the follicle and its duct enters directly into the hair follicle. Hormones control the activity of these glands and as we get older the secretion of sebum decreases, causing the skin to become drier.

• Sebum – is a fatty substance and is the skin’s natural moisturiser. It keeps the skin supple and helps to waterproof it. Men generally secrete more sebum than women. Sebum and sweat mix together on the skin to form an acid mantle. The acid mantle maintains the pH (acid/alkaline level) of the skin.

• Blood and capillary network – blood is supplied to the skin by small blood vessels known as blood capillaries, these enter the lower regions of the dermis and rise to supply the pilo-sebaceous follicles and the sub-epidermal network which also supplies the epidermis. The blood flow within the skin operates as an aid to vital respiration. Capillaries also help with the heat regulation by dilating (widening) and constricting (narrowing) to prevent body heat losses.

• Sensory Nerves – the skin contains sensory nerve endings that detect changes in the environment and send messages to the brain. These nerves respond to touch, pressure, pain, cold and heat and allow us to recognise objects from their feel and shape.

• Motor Nerves – the skin contains motor nerve endings that convey impulses from the brain, though the spinal cord to the muscles, glands and smooth muscular tissue.

• Fibres – nerves are cordlike structures carrying impulses from the periphery, muscles and joints to the brain and spinal cord. Messages pass along the nerve fibres as electrical impulses via a network of interlocking fibres surrounding the upper part of the follicle forming a collar. Fibres extend to the sebaceous glands, epidermis, arrector pili and sweat glands.

Functions of the skin

There are six functions of the skin, which are:

• Sensation – the skin contains sensory nerve endings that send messages to the brain. These nerves respond to touch, pressure, pain, cold and heat and allow us to recognise objects from their feel and shape.

• Excretion – waste products and toxins are eliminated from the skin through the sweat glands.

• Absorption – the hair follicles, the sebaceous gland opening, and the skin are able to absorb, penetration can be affected by the health and condition of the skin.

• Protection – the stratum corneum protects the body against its environment. The structure, rate of replacement and physical repair properties of the outer layer protect against bacterial invasion and minor injury. The skin is waterproof and contains body fluid whilst preventing entry of large quantities of fluid through the epidermis.

• Elimination – sweat is eliminated from the skin to aid heat regulation.

• Heat regulation – it is important for the body to have a constant internal temperature of 36.8 degress Celsius (○C) for our bodies to function. The skin helps to maintain this temperature by:
o Vasoconstriction – this occurs when the body becomes cold. The blood vessels constrict reducing the flow of blood through the capillaries. Heat lost from the surface of the skin is therefore reduced.
o Vasodilation – this occurs when the body becomes too hot. The capillaries expand and the blood flow increases, this allows heat to be lost from the body by radiation.
o Goose bumps – contraction of the arrector pili muscle when we are cold causes the hairs to stand on end, keeping a layer of warm air close to the body. This was probably of more use to our ancestors, who were generally hairier.
o Shivering – when we are cold this helps to warm the body, as the contraction of the muscles produces heat within the body.
o Sweating – in hot conditions the rate of sweat production increases. The eccrine glands excrete sweat onto the skin surface and heat is lost as the water evaporates from the skin.

Skin Types

Skin types vary from person to person and can be described as being normal, dry, oily, combination, sensitive, dehydrated or mature. Essential oils can be chosen to suit each individual skin type.

• Normal – this skin type will look healthy, clear and fresh. It is often seen in children, as external factors and ageing have not yet affected the condition of the skin, although the increased activity of hormones at puberty may cause the skin to become greasy. A normal skin type will look neither oily nor dry and will have a fine, even texture. The pores are small and the skin’s elasticity s good so it feels soft and firm to the touch. It is usually free of sports and blemishes.

• Dry – this skin type is thin and fine and dilated capillaries can often be seen around the cheek and nose areas. The skin will feel and look dry because little sebum is being produced and it is also lacking in moisture. The skin type will often tighten after washing and there may be some dry, flaky patches. There will be no spots or comedones (blackheads) and no visible open pores. This skin type is prone to premature wrinkling, especially around the eyes, mouth and neck.

• Oily – this skin type will look shiny, dull and slightly yellowish (sallow) in colour because of the excess sebum production. Oily skin is coarse, thick and will feel greasy. Enlarged pores can be seen, these are due to the excess production a build-up of sebum. Open pores can let in bacteria, which cause spots and infections. Blocked pores often lead to comedones (blackheads). Oily skin tends to age more slowly as the grease absorbs some of the UV rays and so can protect against damaging effects. The sebum also helps to keep the skin moisturised and prevents drying.

• Combination – with this skin type there will be areas of dry, normal and greasy skin. Usually the forehead, nose and chin are greasy and known as the T-zone. The areas around the eyes and cheeks are usually dry and may be sensitive
• Sensitive – this skin type is often dry, transparent and reddens easily when touched. Dilated capillaries may be present, especially on the cheeks, which gives the face a high, red colour known as couperose skin. Hereditary factors may be a cause of sensitive skin. A skin that is sensitive may be easily irritated by certain substances so care should be taken when choosing products for this type. If a white skin is sensitive to a product it will show as a reddened area, but on black skin it will show up as a darkened area.

• Dehydrated – this skin type lacks moisture and so is dry. The causes include illness, medication, too much sun, dieting and working in a dry environment with low humidity, such as an air-conditioned office. Sebum helps to prevent evaporation of water from the skin, so that when insufficient sebum is produced, moisture is lost from the skin. The skin feels and looks dry and tight. There may be flaking and fine lines present on the skin. Dilated capillaries are also common with this skin type.

• Mature – this skin type is dry as the sebaceous and sweat glands become less active. The skin may be thin and wrinkles will be present. There are usually dilated capillaries, often around the nose and cheek areas. The bone structure can become more prominent as the adipose and supportive tissue become thinner. Muscle tone is often poor so the contours of the face become slack. Because of the poor blood circulation, water products are removed less quickly so the skin may become puffy and pale in colour. Liver spots may also appear on the face and hands. The cause of this skin type is ageing and altered hormone activity

Contagious Conditions
There are four types of contagious conditions which you need to be aware of so that you can recognise them and avoid contact.

1. Virus: There are germs which can only survive in living cells, such as colds, flu, shingles, chicken pox, cold sores, hepatitis, AIDS, warts and verruca’s.
2. Bacteria: Single cell organisms which can multiply very quickly. They are able to breed outside of the body and can therefore be passed on very quickly through contact with contaminated items. Examples: conjunctivitis, impetigo,sty,whitlow
3. Fungus: Consists of moulds and yeast which feed off the waste products of the skin they attack. Examples: Athletes Foot, Nail ringworm, ringworm
4. Infestation: Attack by small parasites which live off human blood – such as scabies mite. This parasite burrows through the skin, lays its eggs which cause an itchy rash and swelling. The track of burros shows up on the skin as greyish ridges. They are usually found on fingers, palms and soles.
   Another example is head lice – tiny insects which lay their ages which attach to the hair, itching and can cause blisters
   

Five conditions where the skin may be contraindicated

• Impetigo – this infection begins when bacteria invade a cut, cold sore or other broken skin. This can be seen as weeping blisters that form golden/yellow coloured crusts. The area around the crusts is inflamed and red. Impetigo is highly infectious and spreads quickly on the surface of the skin. The sufferer must be referred to a doctor and treated with antibiotics. No treatment should be given.

• Shingles – this in an infection caused by the varicella zoster virus, which also causes chickenpox. It is an infection of the nerves supplying certain areas of the skin and is more common in middle-aged and older people. It appears as areas of redness and inflammation. There is itching, and blisters (sacs of fluid) develop along nerve pathways. There may be fever and lethargy too. It is a painful condition and may persist for many months. It is infectious and so no treatment should be given.

• Scabies – the scabies mite burrows into and lays its eggs in the horny layer of the skin. It can affect most areas of the body, although it is commonly found in the webs between the fingers and the cease of the elbow. There is a 4 – 6 week incubation period before the outbreak. The female mite leaves a trail of eggs and excrement is n the skin which appears as wavy grayish lines. The condition is itchy and highly infectious. No treatment should be given and the client should consult their doctor.

• Malignant Melanoma – a melanoma is a skin growth due to over-activity of the melanocytes, usually cause by excessive exposure to the sun. They may be benign, as in a mole, or malignant as in a malignant melanoma. Although rare and not infectious, malignant melanoma are extremely dangerous. They can occur anywhere on the body but often at the site of a mole. They are usually irregular in outline, patchy in colour, itchy or sore and may bleed. They spread very quickly and need prompt medical attention which is why no treatment should be given.

• Ringworm (tinea corporis) – is a fungal infection, not cause by a worm, and is sometimes caught through touching animals. It affects the horny layer of the skin and shows itself as red, scaly, circular patches which spread outwards. The centre of the patch heals, forming a ring shape. It usually appears on the trunk of the body the limbs and the face. Ringworm is highly infectious so no treatment should be given and client should be referred to a doctor