First principles Flashcards
Describe the epidermis
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.
Five layers of epidermis
Stratum corneum Stratum lucidun Stratum granuloseum Stratum spinosym Stratum germinativum
Describe the dermis
- 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
Describe mechanisms of heat regulations in skin
Sweat glands evaporation
Dilation and construction of superficial arterioles
Sub cut tissue
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.
Function of skin
Protection Heat regulations Containment synth and storage Vitamin d Sensation
Describe degrees of burns
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
Describe Bursae
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
Describe the axial and appendicular skeleton
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
Describe Cartilage
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
Describe bones
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.
What are the two types of bones
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.
Discuss classification of bones
1) long bones
2) short bones – carpals and tarsals
3) flat bones
4) irregular bones
5) sesamoid bones
Discuss bone markings
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
Discuss briefly bone developmentq
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)
Describe the vascular supply to bones
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
Describe classification of joints
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
Discuss fibrous joints
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
Discuss cartilaginous joints
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.
Discuss anatomical planes
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.
Describe the basic divisions of the nervous system
CNS and PNS
Autonomic NS and Somatic NS
Discuss CNS anatomy
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.
Describe PNS anatomy
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
Discuss the different types of peripheral nerve cells
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
