First principles

Question 1

Describe the epidermis

Answer 1

Is kertanizzed epithelium that is it has a tough horny superficial layer that provides protective outer surface overlying its regenerative and pigmented deep or basal layer.

The avasuclar epidermis is nourished by the underlying vascular dermis which is supplied by ateries taht enter its deep surface.

Question 2

Five layers of epidermis

Answer 2

Stratum corneum 
Stratum lucidun 
Stratum granuloseum
Stratum spinosym
Stratum germinativum

Question 3

Describe the dermis

Answer 3

• Interlacing collagen and elastic fibres,
• Deep layer contains hair, sweat and sebaceous glands
• Arector muscle (smooth) cause folices to stand on end, -due to position of sebaceous gland makes them secrete

Question 4

Describe mechanisms of heat regulations in skin

Answer 4

Sweat glands evaporation

Dilation and construction of superficial arterioles

Question 5

Sub cut tissue

Answer 5

Composed of lose connective tissue and stored fat
Cutaneous ligaments extend through this layer connecting deep dermis to underlying deep fascia
Contains sweat glands, superfical blood vessels lymphatic vessles and cutaneous nerves.

Question 6

Function of skin

Answer 6

Protection 
Heat regulations 
Containment 
synth and storage Vitamin d
Sensation

Question 7

Describe degrees of burns

Answer 7

1st: epidermis only, pain erethema, oedema heals well nil scar
2nd: epidermis and superficial dermis very painful, unless very superficial glands and hair follicles survive and can provide base for regeneration of basal epidermis slow healing 21 days scar
3rd: full thickness: painless, nil healing skin graft

Question 8

Describe Bursae

Answer 8

Closed sacs or envelopes of serous membrane that are collapsed and essentially empty except for a thin layer of lubricating fluid secreted by the membrane

Bursae allow one structure to move freely over another

Question 9

Describe the axial and appendicular skeleton

Answer 9

The axial skeleton consists of:

1) the bones of the head (cranium or skull)
2) the bones of the neck (hyoid and cervical vertebrae)
3) bones of the trunk (ribs, sternum, vertebrae and sacrum)

The appendicular skelton consists of the bones of the limb including those forming the pectoral and pelvic girdle

Question 10

Describe Cartilage

Answer 10

Is a resilient semirigid form of connective tissue that forms parts of the skeleton where more flexibility is required.
Blood vessel do not enter cartilage and as such they are avascular

Question 11

Describe bones

Answer 11

A fibrous tissue covering surrounds each skeletal element like a sleeve except for where articular catrilage occurs; that surrounding bones is the periosteum that surrounding cartilages is the perichondrium.
The periosteum and perichondrium nourish the external aspects of the skeletal tissues.

Question 12

What are the two types of bones

Answer 12

1)Compact

2)Spongy
All bones have a superifical thin layer of compact bone surrounding a central mass of spongy medullary bone, wxcept where the latter is replaced by a medullary cavity.

• Compact bones provide strength for weight beaering
• in long bones designed for rigidity and attachment of mucles and ligaments the amount of spongy bone is greatest near the middle of the shaft where the bones is liable to buckle.

Question 13

Discuss classification of bones

Answer 13

1) long bones
2) short bones – carpals and tarsals
3) flat bones
4) irregular bones
5) sesamoid bones

Question 14

Discuss bone markings

Answer 14

Capitulum: small, round articualr head

Condyle: rounded, knuckle-like articular head

Crest: ridge of bone

Epicondyle: eminence superior to a condyle

Facet: smooth flat area usually covered with cartilage

Fossa: hollow or depressed area

Protuberance: projection of bone

Spine: thorn-like process

Trochlea: spool-like articular process

Question 15

Discuss briefly bone developmentq

Answer 15

Most bones take many years to grow and Mature. The humerous for example begins to ossify at the end of the embryonic period but does not finish ossifying until 20 years of age,
All bones a derived from the mesenchyme from two processes
1) intramembranous ossification (directly from mesenchyme)
2) endochondrial ossification (from cartilage derived form mesnychyme)

Question 16

Describe the vascular supply to bones

Answer 16

Bones are richly supplied by blod vessels
The most apparent are the nurtrient arteris that arise as indepedent branches of adjacent arteries outside the periosteum ans pass obliquely through the compact bone of the shaft of a long bone via nutrient foramina

The nutrient artery divied in the medullary cavity into longitudinal branches that proceed toward each end

many small arteries from the periosteum are responsible for supplying compact bone

Osteocytes are supplied by microscopi canal system the haversion systymes

Metaphysial and epiphyseal arteries supply their namesake and arise mainly from arteries that supply the joints

Question 17

Describe classification of joints

Answer 17

The articulating bones of synovial joints are united by a joint capsule spanning and enclosing the articular cavity.
The articular cavity of a synovial joint is a potential space that contains a small amount of lubricating synovial fluid
Inside the capsule articular cartilage covers the articular surfaces of all bones, all other internal surfaces are covered by a synovial membrane
Synovial joints are the most common joint and for free movement between the bones they join.
The six major synovial joints include
1) plane joints which permit gliding
-AC joint

2) Hinge joints
- knee
- elbow

3) saddle joints permit adduction and abduction as well as flexion and extension
- carpometacarpal joint

4) Condyloid joints permit flexion and extension as well as adduction and abduction
- MCPJ

5) Ball and socket

6) pivot joint uniaxial
- Alantoaxial joint

Question 18

Discuss fibrous joints

Answer 18

The articulating bones of fibrous joints are united by fibrous tissue.
The amount of movement occurring at a fibrous joint depends in most cases on the length of the fibers uniting the articulating bones.
-Intercranial joints
-interosseous membrane

Question 19

Discuss cartilaginous joints

Answer 19

The articulating structures of catilagionous joints are united by hyaline cartilage or fibrocartilage.

In primary cartilaginous joints the bones are united by hyaline cartilage which permits slight bending during early life. Primary cartilaginous joints are usually temporary such as those present during the development of a long bone.

Secondary cartilaginous joints or symphyses are strong slightly movable joints united by fibrocartilage. The fibrocartilaginous intervertebral discs between the vertebrae.

Question 20

Discuss anatomical planes

Answer 20

Median plane: The vertical plane passing longitudinallly thorugh the body divides the body into right and left

Saggital plane: are vertical planes passes through the body parallel to the median plane.

Frontal (coronal): are vertical planes passing through the body perpendicular to the median plane, giving rise to anterior and posterior

Transverse (axial) planes passing perpendicular to the saggital and coronal planes splitting the body into superior and inferior portion.

Question 21

Describe the basic divisions of the nervous system

Answer 21

CNS and PNS

Autonomic NS and Somatic NS

Question 22

Discuss CNS anatomy

Answer 22

Consists of the brain and spinal cord
A collection of nerve bodies in the CNS is called a nucleus, a bundle of nerve fibres connecting neighboring or distant nuclei of the CNS is a tract.

Composed of grey and white matter
Gray matter constitute the nerve cell bodies
white matter the tracts

In cross section of the spinal cord the gray matter appears as a roughly as a H shaped area the struts of the H are horns they are right and left and posterior and anterior horns

Three membranous layers constitue the meninges

1) pia mater
- intimately cover the brain and spinal cord

2) arachnoid mater
- CSF located between arachnoid and pia

3) dura mater
- intimately related to the internal aspect of the bone of the surrounding neruocranuim

The meninges and and the CSF surround and protect the CNS.

Question 23

Describe PNS anatomy

Answer 23

Consists nerve fibers and cell bodies outside of the CNS that conduct impulses away or towards the CNS

It is important to distinguish between peripheral nerve fibres and peripheral nerves

Peripheral nerve fibres consists of an axon its neurolemma and surrounding endoneurial connective tissue. The neurolemma consists of the neurolemma cells (schwann) that immediately surround the axon. Can be mylinated or unmyelinated

A peripheral nerve consists of

1) a bundle of peripheral nerve fibres
2) connective tissue covering that surround adn bind the nerve fibres
3) blood vessels ( vaso nervorum)

Peripheral nerves are fairly strong and resilient because the nerve fibers are supported and protected b three connective tissue coverings

1) endoneurium
2) perineuroim
3) epineurium

Question 24

Discuss the different types of peripheral nerve cells

Answer 24

The PNS is anatomically and operationally continuous with the CNS. Its afferent fibers convey neural impulses to the CNS from the sense organs. Its efferent convery neural impules to effector organs.

Peripheral nerves are either cranial or spinal
Cranial
-exit the cranial cavity through foramina in the cranium

Spinal nerves
-exit the vertebral column through the intervertebral foramina

Question 25

Discuss spinal nerves

Answer 25

Spinal nerves initially arise as rootlets which converge to form two nerve roots
1) anterior (ventral) root consisting of motor fibers passing from nerve cell bodies in the anterior horn of the spinal grey matter to effector organs

2) posterior( dorsal roots) consisting of sensory fibres from cell bodies in the spinal sensory or posterior root ganglian

The posteior and anterior nerve roots unit within or just proximal to the intervertebral formen to form a mixed spinal nerve which immediatly divides into two primary rami a posteior and anterior. The anterior and posterior rami contain both sensory and motor fibres

Question 26

Define dermatome and myotome

Answer 26

Dermatome
The unilateral area of skin innerveated by the fibers of a single spinal nerve

Myotome
the unilateral muscle mass receiving innervation from the fibers conveyed by a single spinal nerve

Question 27

Describe somatic fibers

Answer 27

Have general sensory and motor fibers

Sensory fibres
-transmit sensation from the body to the CNS, they may be exteroreceptive sensation from the skin (pain, temp, touch and pressure) or pain and proprioception from muscles tendons and joints.

Motor fibres
-transmit impulses to skeltal muscles

Question 28

Describe visceral fibers

Answer 28

Have general sensory and motor fibers

Sensory
-transmit pain or subconcious visceral reflex sensation (information concerning distension, blood gas and blood pressure) form hollow organs and blood vessels

Visceral motor
-transmit impulses to smooth muscle and glandular tissue

Question 29

Discuss the autonomic nervous system

Answer 29

Consists of motor fibers that stimulate smooth muscle, modified cardiac muscle and glandualr cells.

The efferent nerve fibers and ganglia of the ANS are organized into parasympathetic and sympathetic. Unlike the CNS and somatic nervous system which involve a single neuron in both divisions of the ANS conduction of impulses from the CNS to effector organs involves a serios of two multipolar neruouns.

The cells of the firs tpresynaptic neuron is located in the fray matter of the CNS. Its fiber synapses only on the cell body of a postsynaptic neuron the second neruon in the series. The bodies of these second neurons are located oustide the CNS in autonomic ganglia

Question 30

Describe the sympathetic division

Answer 30

The cell bodies of the presynaptic neurons of the sympathetic division is found only in the intermediolateral cell columns. The IMLs are organised somatotopically (IE arranged like the body with fibres supplying superior structures superior int he column) m

The cell bodies of postsynaptic neurons occur in two location

1) paravertebral ganglia are linked to form right and left sympathetic trunks on each side of the vertebral column and extend essentially the length of this column
2) prevertebral ganglia are in plexuses that surround the origins of the main branches of the abdominal aorta such as the two large celiac ganglia

Sympathetic leave the anterior roots and enter the anterior rami of spinal nerve and almost immediatly leave the rami to pass to the sympathetic trunks

Within the trunk they can follow four different paths
1) ascend in the sympathetic trunk to synapse with a postsynaptic neuron of a higher paraverebral ganglian

2) Descend in the sympathetic trunk to synapse with a postsynaptic neuron of a lower paraverebral ganglian
3) enter and synapse immediately with a postsynaptic neruon at the same level
4) pass through the sympathetic trunk without synapsing continuing through an abdominopelvic splanchinic nerve.

Question 31

Describe the parasympathetic

Answer 31

Presynaptically the parasympathetic neuron cell bodies are loctaed in two sites
1) gray matter of the brainstem the fibers exit the CNS within cranial nerves these fibers consitute the cranial parasympathetic outflow

2) In the gray matter of the sacral segments of the spinal cord. fibers exit the CNS through the anterior roots of sacral spines these fibers constitute the sacral parasympathetic flow

The cranial outflow provide parasympathetic innervation to the head and the sacral outflow provide the parasympathetic innervation of the pelvic viscera.
In terms of thoracic and abdominal viscera the cranial outflow through the vagus nerve dominants.

Four discrete pairs of parasympathetic ganglia occur in the head. Elsewhere presynaptic parasympathetic fibers synapse with postsynaptic cell bodies which occur singly in or on the wall of the target organ. Most presympathetic fibers are very long