• Share
  • Email
  • Embed
  • Like
  • Save
  • Private Content
2446 Anatomy 00 Pre B
 

2446 Anatomy 00 Pre B

on

  • 845 views

 

Statistics

Views

Total Views
845
Views on SlideShare
845
Embed Views
0

Actions

Likes
0
Downloads
13
Comments
0

0 Embeds 0

No embeds

Accessibility

Categories

Upload Details

Uploaded via as Adobe PDF

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

    2446 Anatomy 00 Pre B 2446 Anatomy 00 Pre B Document Transcript

    • 1111 2 3 4 5 6 7 8 Contents 9 10111 1 Preface to the 3rd Edition v 2 3 Introduction vii 4 5 6 Chapter 1 Introduction to Anatomy and Physiology 1 7 Chapter 2 Histology 5 8 9 Chapter 3 The Skeletal System 11 20111 Chapter 4 The Muscular System 25 1 2 Chapter 5 The Vascular System 39 3 Chapter 6 The Neurological System 50 4 5 Chapter 7 The Digestive System 60 6 Chapter 8 The Respiratory System 68 7 8 Chapter 9 The Genito-Urinary System 74 9 Chapter 10 The Endocrine System 80 30111 1 Chapter 11 Accessory Organs 86 2 General glossary of anatomy and physiology 95 3 4 Index 99 5 6 7 8 9 40111 1 2 3 4 5 6 7 8 9 50111 51 52 53111 iii
    • THE STUDY OF ANATOMY AND PHYSIOLOGY 1111 2 3 4 6 5 6 7 8 The Neurological System 9 10 1 The neurological (or nervous) system transmits and 2 3 receives messages to and from the brain and all parts of 4 the body. There are two main divisions: 5 6 q the central nervous system, also known as the 7 cerebrospinal system because it consists of the brain 8 and the spinal cord 9 20 q the autonomic nervous system, which includes the 1 sympathetic system and the parasympathetic system. 2 3 4 5 6 7 8 9 30 1 2 3 4 5 6 7 8 9 40 DIAGRAMMATIC VIEW OF 1 A NERVE SHEATH 2 3 4 5 6 7 8 9 50 51 52 53111 A NEURON 50
    • THE NEUROLOGICAL SYSTEM 1111 The basis of the nervous system is the nerve cell or neuron. This consists 2 of a nerve cell body with its receiving processes, the dendrites, and its 3 transmitting process, the axon and its nerve endings. White nerve fibres 4 are medullated, that is they are enclosed in a sheath of myelin. Grey nerve 5 fibres are non-medullated, that is, they have no myelin. 6 7 8 9 10111 1 2 3 4 5 6 7 8 9 20111 1 2 3 4 5 6 7 8 9 30111 1 2 3 A MEDULLATED NERVE 4 5 6 7 8 9 THE PATHWAY OF A NERVE IMPULSE 40111 1 2 3 4 The central nervous 5 6 system 7 8 The brain The brain is at the centre of the central nervous system. It is well 9 protected from the outside by the hard bone structure of the skull. 50111 Inside, the brain is protected by three membranes, the meninges: 51 52 q the outer layer, the dura mater (strong or hard mother), which is 53111 constructed of strong fibrous tissue anchored to the skull 51
    • THE STUDY OF ANATOMY AND PHYSIOLOGY 1111 q the middle layer, the arachnoid, which is more delicate than the dura 2 mater and is not anchored to the skull. Beneath it is a large 3 reservoir of cerebral spinal fluid which surrounds the brain and on 4 which it rests 5 q inner layer, the pia mater (soft mother), which is in contact with the 6 grey matter of the brain itself and dips deep down between the 7 brain convolutions. 8 9 The adult human brain weighs rather more than 1360 g and is so full of 10 water that it tends to slump rather like a blancmange if placed without 1 the support of a firm surface. It is estimated that it has 12 billion 2 neurons or nerve cells. 3 When we speak of the brain we are really considering three quite 4 different structures: 5 6 q the cerebrum 7 q the cerebellum 8 q the medulla oblongata. 9 20 1 2 3 4 5 6 7 8 9 30 1 2 3 4 5 6 A SECTION THROUGH 7 THE BRAIN 8 9 The cerebrum 40 The cerebrum consists of two symmetrical hemispheres. The outer layer 1 of the cerebrum is known as the cortex and this is arranged in convolu- 2 tions, that is deep irregularly shaped fissures or indentations. This is the 3 grey matter of the brain. Underneath the cortex lies nerve fibre or white 4 matter. The function of the cerebrum is to control voluntary movement 5 and to receive and interpret conscious sensations. It is the seat of the 6 higher functions such as the senses, memory, reasoning, intelligence 7 and moral sense. 8 9 50 The cerebellum 51 The cerebellum is much smaller in size and lies below and behind the 52 cerebrum. It too has grey matter under which is white matter. Its 53111 function is to control muscular co-ordination and balance. 52
    • THE NEUROLOGICAL SYSTEM 1111 2 3 4 5 6 7 8 9 10111 1 2 3 4 5 6 7 8 9 20111 1 2 3 4 THE BRAIN VIEWED FROM BELOW 5 6 7 8 The medulla oblongata 9 The medulla oblongata is about 3 cm long, tapering from its greatest 30111 width of 2 cm and connecting the rest of the brain with the spinal cord 1 with which it is continuous. It is made up of interspersed white and grey 2 matter. The medulla oblongata not only acts as the link between the 3 brain and the central nervous system of the body but it is also the 4 centre of those parts of the autonomic nervous system which control 5 the heart, lungs, processes of digestion, etc. 6 Other parts of the brain include: 7 8 q the pons varoli 9 q the pituitary gland 40111 q the hypothalamus. 1 2 3 The pons varoli 4 The pons varoli is a bridge of nerve fibres linking the right and left 5 hemispheres and also the cerebellum with the cerebrum above and the 6 medulla oblongata below. All impulses which pass between the brain 7 and the spinal cord traverse the pons varoli. 8 9 50111 The pituitary gland 51 The pituitary gland (or hypophysis) is a small gland about the size of a 52 pea and lies in the pituitary fossa in the base of the skull. Its function is 53111 dealt with in Chapter 10, the Endocrine System. 53
    • THE STUDY OF ANATOMY AND PHYSIOLOGY 1111 The hypothalamus 2 The hypothalamus is situated in the area of the floor of the third 3 ventricle of the brain and it exercises an influence over the autonomic 4 nervous system. It contains the heat regulating centre and is generally 5 believed to be involved with appetite. 6 7 8 The spinal cord The spinal cord, which is continuous with the medulla oblongata, extends downwards through the vertebrae of the spinal column. The 9 cord itself is cylindrical in shape with an outer covering of supporting 10 cells and blood vessels and an inner egg-shaped core of nerve fibres. 1 It extends through four-fifths of the spinal column and is about 45 cm 2 in length. 3 4 5 6 7 8 9 20 1 2 3 4 5 6 7 8 9 30 1 2 3 4 5 6 7 8 9 40 1 2 3 THE POSITION OF THE SPINAL CORD A SECTION THROUGH THE SPINAL CORD 4 5 6 7 8 Nerves There are 12 pairs of cranial nerves given off from the base of the brain; 9 31 other pairs branch off the spinal cord throughout its length. These 50 extend to every part of the body. Nerves that extend upwards through 51 the spinal cord to the brain pass through the medulla oblongata where 52 they cross – thus the left-hand side of the brain controls the right-hand 53111 side of the body, whilst the right-hand side of the brain controls the 54
    • THE NEUROLOGICAL SYSTEM 1111 left-hand side of the body. Nerves of the central nervous system fall 2 into three categories: 3 q motor or efferent nerves, whose primary function is to control the 4 movement of muscles 5 6 q sensory or afferent nerves, which carry impulses from the sensory nerve 7 endings to the spinal column and the brain 8 q mixed nerves, which consist of both motor and sensory fibres. 9 10111 1 2 Cranial nerves 3 Name Type Function Number 4 5 Abducent Motor Supplies lateral rectus muscles of eyes 6 6 7 Auditory Sensory Sense of hearing, maintenance of balance, 8 8 equilibrium 9 20111 Facial Mixed Sense of taste from tongue and impulses 7 1 to muscles of facial expression 2 3 Glosso-pharyngeal Mixed Sensations from tongue, impulses to muscles 9 4 of pharynx 5 Hypoglossal Motor Supplies tongue muscles 12 6 7 Oculomotor Motor Supplies muscles operating eyes 3 8 9 Olfactory Sensory Sense of smell 1 30111 Optic Sensory Sense of sight 2 1 2 Trochlear Motor Supplies superior oblique muscles of eyes 4 3 4 Trigeminal Mixed Receiving pain, heat, pressure and stimulating 5 5 muscles of mastication 6 7 Spinal Motor To sterno-cleido mastoid and trapezius muscles 11 8 accessory 9 Vagus Mixed Sensory, motor, digestive and respiratory 10 40111 organs 1 2 3 4 5 Spinal nerves 6 The 31 pairs of spinal nerves comprise: 7 8 q 8 pairs of cervical nerves 9 q 12 pairs of thoracic nerves 50111 q 5 pairs of lumbar nerves 51 52 q 5 pairs of sacral nerves 53111 q 1 pair of coccygeal nerves. 55
    • THE STUDY OF ANATOMY AND PHYSIOLOGY 1111 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 20 1 2 3 4 5 6 7 8 9 30 1 2 3 4 5 6 7 8 9 40 1 2 3 4 5 6 7 8 9 50 51 52 53111 NERVES (POSTERIOR BODY) NERVES (ANTERIOR BODY) 56
    • THE NEUROLOGICAL SYSTEM 1111 2 3 The autonomic This controls all body structures over which we have no voluntary control. It is divided into two separate parts: 4 5 nervous system q the sympathetic system 6 q the parasympathetic system. 7 8 9 The sympathetic system The sympathetic system comprises a gangliated cord which runs on 10111 either side of the front of the vertebral column. The principal plexuses 1 of this system are: 2 q the cardiac plexus, which supplies all the thoracic viscera and the 3 thoracic vessels 4 5 q the coeliac or solar plexus, which supplies all the abdominal viscera 6 q the hypogastric plexus, which supplies the pelvic organs. 7 8 9 The parasympathetic system The parasympathetic nervous system consists mainly of the vagus nerve which gives off branches to the organs of the thorax and abdomen, but 20111 also includes branches from other cranial nerves, mainly the third, 1 seventh and ninth as well as nerves in the sacral region of the spinal 2 column. 3 4 All the internal organs therefore have a double nerve supply from the 5 sympathetic and parasympathetic systems and their effect is opposite – 6 simply, a sympathetic nerve has the effect of increasing body activity 7 and speeds it up, whereas the parasympathetic, on the contrary, slows 8 down body activity. 9 The sympathetic fibres increase the heart rate, raise the blood pressure, 30111 mobilise glucose, stimulate the secretion of sweat. The parasympathetic 1 fibres slow the heart, lower the blood pressure and decrease the 2 secretion of sweat. It has been maintained that the sympathetic system 3 provides for today’s work and that its action increases when involved 4 with physical activity. The parasympathetic, on the other hand, looks 5 after tomorrow, being mainly concerned with changes which take place 6 during rest. 7 8 The sympathetic nerves are stimulated by strong emotions such as 9 anger and excitement. In fact it is because of this effect of the emotions 40111 that they are called sympathetic. 1 The adrenal is one of the glands which they stimulate and the liberation 2 of adrenalin is one of the body’s responses to anger. In some people, 3 the parasympathetic nerves are the stronger and hold the balance in 4 the body; such people generally have a placid disposition, good 5 digestion and are not very easily disturbed. These are known as vagotonic 6 types. In other people, the sympathetic nerves are the stronger and 7 these people are more emotional, less stable and their digestion is 8 more readily disturbed. These are known as sympatheticotonic types. 9 50111 Another function of the autonomic nervous system is related to the 51 reflex nervous action. This is an involuntary reaction to a stimulation, 52 for example, taking the fingers away quickly from a hot surface, the 53111 recovery of balance to prevent a fall, and so on. It is also within this 57
    • THE STUDY OF ANATOMY AND PHYSIOLOGY system that a reflex action is conditioned. For example, the normal reflex 1111 action when handed a very hot plate would be to drop it, but as this 2 action would carry with it certain distinct disadvantages, like loss of 3 the meal that was on the plate or the work involved with clearing up 4 afterwards, the plate – instead of being dropped – is quickly put 5 down. That is a reflex action which has been conditioned by other 6 considerations. 7 8 9 10 1 Conditions and diseases of the neurological system 2 3 4 Neuritis This takes in a wide group of disturbances which affect the peripheral nerves after they leave the spinal cord. Some of the disturbances are 5 due to infection, others to compression of the nerves. Probably the 6 biggest single factor is the build-up of urea and lactic acid at a point, or 7 points, of the nerve’s course, which affects the nerve’s sheathing. 8 9 20 1 Bell’s Palsy 2 (Facial paralysis) This is a neuritis of the facial nerve usually caused by infection and 3 compression of the swollen nerve as it passes through a tiny opening in 4 the skull below the ear in its course to the muscles of the face. 5 6 7 Neuralgia This is a painful condition in a nerve due to irritation, inflammation or 8 exposure. 9 30 1 Parkinson’s Disease Otherwise known as Paralysis Agitans, this is an extremely common 2 illness beginning in middle life, deriving from disease of the basal 3 ganglia. The disease is slowly progressive but, as it does not affect the 4 brain, intelligence is unaffected. The chief symptoms of this illness are 5 tremor, rigidity and slowness of movement. 6 7 8 Sciatica This is inflammation of the great sciatic nerve, the longest single nerve 9 in the body. This is often a form of rheumatic neuritis but it can also be 40 caused by compression, an arthritic spur or a prolapsed intravertebral 1 disc. 2 3 4 5 6 GLOSSARY 7 8 9 Brachial neuritis a condition similar to sciatica but in the arm 50 51 Ganglia a group of nerve cell bodies usually located outside the brain and 52 spinal cord 53111 58
    • THE NEUROLOGICAL SYSTEM 1111 2 Plexus a network of interlacing nerves 3 4 Spasticity a stage of sustained contraction of a muscle associated with an 5 exaggeration of deep reflexes 6 7 Synapse the region of communication between neurons; the point at which an 8 impulse passes from an axon of one neuron to a dendrite of the cell 9 body of another 10111 1 2 3 4 5 6 7 NERVE SYNAPSE 8 9 20111 1 2 3 4 5 6 7 8 9 30111 1 2 3 4 5 6 7 8 9 40111 1 2 3 4 5 6 7 8 9 50111 51 52 53111 59