Module 7 Wk 1 Flashcards
what does the integument consist of?
- the skin
- the hair and a variety of skin associated glands (adnexa)
- claws, hoofs and horns – modified version so the skin as retain many processes we see in the development of the skin
Describe the different function of the integument
- Protective -wear and tear
- Barrier- microbial
- penetration/ impermeable to - - water
- Thermoregulation
- Sensory perception
- Storage organ – in the hyperdermis part of skin has white fatty deposis which is used for stored energy and making new skin
- Synthesis Vit D3
- Glandular – sebum and sweat - secretions
- Photo-protection/ sensitisation
- Immuno-surveillance - in underlying CT of skin cells sitting monitoring
- Capture of prey…..
Describe the Epidermis
stratified keratinised squamous epithelium
Describe the Dermis?
dense irregular CT
What is another name for the stuctures found in the dermis and what are they?
Adnexa - hair follicules, sweat glands, sensory innervation, venous supply and sm to deterimine if hair stands up or not
Describe the subcutis and what it is made up of?
- superficial facia
- adipose tissue - enegy and fat store
- allows skin to move over underlying muscles
What is the condition of animals coat or skin a good indicator of?
whats going on internally
Describe the embrylogical development of the skin
- Primitive Epidermis is of ectodermal origin and Dermis is of mesodermal origin
- Basal cells undergo proliferation, migration and differentiation resulting in cell death
- Stratified keratinised squamous epithelium – forms a physical and permeability barrier
- Melanocytes from neural crest origin migrate to the dermal–epidermal border. Responsible for pigmentation of the skin
What are the main types of cells in the epidermis layer and descrip them
- Basal cells - stem cells (undifferentiated)
- Keratinocytes - differianteaite, migrate and become keratonised
What are the other cell types assocaited with the epidermis
- Melanocyte - responible for the synthesis of the pigment of melanin
- Merkel cell - has sensory function
- Langerhans cell - monitoring function picking up anything getting through the top barriers
What happens to the melanin produced by melanocytes?
transferred to stem cells and sits above nuclei, protecting them from UV light
Name the two main types of hair follicle associated with the skin of domestic species
simple and compound
What are the different types of strata in epidermis
stratum basale, stratum spinosum, strata granulosum, strata lucidum and strata corneum
Describe the stratum basale layer
- Mitotically active layer where cells divide and move outwards towards stratum spinosum
What appears in the cytoplasms and is the first sign of keratinisation
Tonofilaments
Describe the stratum spinosum layer
- cells have prominent cell-to-cell junctions called desmosomes that appear as spiky membrane projections
- Tonofolaments increase in quantity becoming major feature
- Lamellar bodies appear in cytoplasm - organelles containing lipid which are extruded as cells enter granulosa - waterproofing of the skin
- Cells become progressively flattened
Describe the Stratum Granulosum layer
- nucleaus and organells start to break down.
- keratohyakin granules start to appear which are precurser proteins of filaggrin and loricrin
- laminar bodies release lipis between cells which helps with waterproofing
Describe the purpose Filaggrin has in struatum granulosum
It causes tonofilaments to aggregrate and form tonofibrils
Describe the purpose Loricrin has in struatum granulosum
It contributes to form prtective thickened cell envelopes
What do the specail cell juntion do to the dead squames and where is the process absent?
- rivet them together
- absent in the outer most layer
Describe what the control of desquamation at the surface depends on
Balance between levels of protease inhibitors & proteases (latter cause enzymatic degeneration of desomsomes junctional complexes which anchor the cells to the surface)
Describe the histological appearance of the epidermis on thick hairless skin
- Epidermis thick
- Stratum corneum (SC) is particularly thickened (12-20 layers)- subject to constant abrasive forces
- Dermal-epidermal border interdigitates – anchors epidermis to dermis – when these come away from each other si where we get blistering
- No hair follicles are present
- Sweat glands (eccrine) are often present in the dermis
Describe the histological appearance of the epidermis on thick hairy skin
- Epidermis is very thin (arrow) - different strata can still be recognised at high mag
- Characteristic feature - presence of Hair follicles (H) plus associated sebaceous (S) and sweat glands (A) all in the dermis
Describe what the Dermis (CT) consists of
- Cells
(fibroblasts*, also mast cells, plasma cells, macrophages, adipocytes, melanocytes, lymphocytes, neutrophils etc) - Fibers
Different types and proportions (Collagen, reticular, and elastic fibers) - Ground substances
Dense fluid (proteoglycans and glycoprotein)
*Fibroblasts produce /maintain the extracellular matrix
Where is the blood supply to the skin loacted?
Dermis
Describe the blood supply in skin
- supply is taken up close to the epidermis but not in
- blood then goes into superficial plexus
- then into the middle then the deep plexus
Describe how the body adapts so heat loss is limited when cold
Due to taking it up close to the epidermis you are losing heat to the outside so the supply bybasses this step using an AV shunt so not losing heat to the surface
WEhere does hair not cover on animals?
- food pad, hoof, glans penis, mucocutaneous junctions and teat of some species
what is hair produced by?
- a hair follicule in the dermis of the skin
State the functions of hair
- mechanical protection
- thermoregulation
- sensory perception- specialised tactile hair
What is the name of the muscle associated with hair?
Arrector pili muscle - contacts to make hair stand up
Describe the structure of a simple hair follicule
- A simple hair consists of a cuticle, cortex and medulla
- The hair shaft projects above the surface of the skin epidermis
- The rest of the follicle is embedded within the dermis (and hypodermis)
- The hair is anchored within the follicle
- The root of the hair consists of the hair and surrounding root sheaths
- The bulb consists of the dermal papilla and hair matrix cells (stem cells)
- Cells become keratinized in the Keratogeneous zone
What does the activity of the matrix cells depens on?
dermal papilla
where do the migrating matrix cells pass through
the keratogenous zone
what do the matrix cells differentaite into?
to form hair and int. root sheath
What cells are responsible for the pigmentation?
melanocytes
Describe the different phases of the hair cycle?
ANAGEN = growth phase:
Hair bulb matrix cells are mitotically active
CATAGEN = regressive stage
Cellular proliferation decreases / cease
Hair bulb = flimsy disorganised column of cells
Club hair.
TELOGEN = resting or quiescent phase.
Hair remains anchored by Keratogeneous rootlets
Dermal papilla = ball of cells below the capsule of the germ cells of the hair bulb.
Dermal papilla away from deral cells but there will be recontection
Hair continuous to lengthen
RENEWED ANAGEN = formation of new hair
Re-establishment of matrix/dermal papillae relationship
Mitotic activity/ keratinisation begin.
Forces root of old hair to move towards the surface . And small hair starts growing into
Hair no longer anchored
When there is lameness is the limb of dog or cat which stuctures are usually effected?
proximal
When there is lameness is the limb of large animal which stuctures are usually effected?
distal
Define Locomotion?
ability to move body forward
Define the musculoskeltal system?
skeleton and all associated soft tissue structures
Define the function of muscle?
support and movement of body
What is the movement called of a limb moving crainally to trunk
protraction
What is the movement called of a limb moving caudally to trunk
retraction
What is the movement called of a limb moving medially to trunk
adduction - moving towards midline
What is the movement called of a limb moving laterally to trunk
abduction - moving away from midline
folding/shortening movements within limb are called what and what happens to angles between joints?
flexion - angles decrease between joints
stretching/ lengthening movements within limb are called what and what happens to angles between joints?
extension - angles increase
Describe the interaction between limbs and trunk when moving forward
each limb goes throught the 4 stages -
- folding limb - flexion
- moving limb forward - protaction
stretching limb - extention - moving limb back wards - retraction
T/F hindlimbs have the most contribution during forward perpulsion?
True
What kind of animal will have less flexibiloty in their trunks?
Herbivores with high fiber diets and bulky abdominal viscera
Where in horse does most of the perpulsion come from?
limb movement
What in cats helps with perpulsion?
flexible vertebral column
What do joints allow?
movement between bones
what do ligaments do?
hold bones together
what does skeletal muscle produce?
Movement between bones across joints - one at diatal end and one at proximal and whne contact bring together
What attaches muscle to bones across joints?
Tendons - continuation of muscle in areas where you dont want bulkyness so have the ropey like tendons
Describe long bones?
- provide support and leverage in limbs
Describe flat bones?
- Large surface area for muscle attachment
- Protection of underlying structures
Describe short bones?
- Some rotation of individual bones (as a group allow large range of movement)
- Ligaments attachments them
- Anti-concussive / shock absorption
Describe a sesamoid bone?
- Embedded in tendons
- Redirection of forces over angled surfaces
- Reduction of friction (damage prevention)
Describe an irregular bone?
- midline/ axail location
Describe the patella?
(equivalent to kneecap) – largest sesamoid in the bone, part of the stifle (equivalent of knee joint) embedded into quadriceps tendon. Ensures that the tendon over the stifle joint is maintained in an axial plane and protects tendon from wear and tear from the underlying femur (by providing a smooth surface for the tendon to move on).
what are the sites for attachment of importnant stuctures called on bones?
specific bony contours
Describe smooth surface areas on bones
Articular / joint surfaces
- Covered by hyaline cartilage
- Subchondral bone
- Osteochondral junction
- No periosteum
Describe rough surface areas on bones
Covered by periosteum in life
Areas for general muscle attachment
what is an Osteochondral junction
boundary between the smooth surface area and rough surface area (in life = boundary between periosteum and hyaline cartilage), etymology: osteo – bone, chondral – cartilage. The joint capsule will attach around this area.
what is a subchondral bone
smooth areas – cartilage (basically means area under the cartilage)
What is the periosteam?
thin layer of cells providing blood supply to bone
how do bones appear on radiographs
whitw/radio- opaque
in utero what is the primordail skeleton made of?
cartilidge
Describe bone growth
- endochondral ossidication (bone growth within cartiloidge
- chondrocytes become quite active and die leavinf behind holes where blood supply comes trhough with osteoblasts
- the osteoblast replace those spaces
- the same thing happens at the distal end but will stay active at the centre always creating elongation of the bone
where in the adult limb is the weakest point?
shaftw
What must you not mistake for fractures on a radiograph?
Physis/ growth plate
where in the young limb is the weakest point?
growth plate
name the 3 times of joints and examples of each
- Fibrous - skull sutures, radius and ulna
- cartilagenous - pelvic and mandibular symphysis
- synovial - elbow, stifle
describe the fibrous joints
- little movement
- bones joined by dnese conjunctive tissue
Describe cartilagenous joints
- flxible
- little movement as they grow
Describe synovial joints
- large range of movement
- most limb joints
- two articulating bones are seperated by a fluid-filled space termed joint cavity
name all 5 features of synovial joints
Hyaline cartilage
synovail fluid
synovail membrane
joint caupsule
collateral ligaments
Describe hyaline cartilage
- Covers articular surface
- Reduces friction
- Shock absorption (flexible)
- No blood vessels or nerve endings
Describe synovail fluid
- lubrication and nurtrition
- viscous fluid
what is a physical barrier of the synovail joints?
synovail membrane
what is the joint capsule
fiberous layer outside synovail membrane - incased - attaching around the osteochondral junction
what are the collateral ligaments formed from
joint capsule
what is the major muscle group located dorsal to vert column
epaxial
what is the major muscle group located ventral to vert column
hypaxail
describe extrinsic limb muscles
- origin axail and insertion appendicular skeletons
- move limb relative to trunk
describe the intrinsic limb muscles
Origin & insertion within limb so apendicular
movement within limb
what are the 3 cursorail adaptations of the proximal
1.Reduced pectoral skeleton
More cranial/ caudal movement
Clavicle absent / vestigial
Deep, narrow chest
2.Elongation at proximal end of limb
Scapula lies lateral and vertical
3.Elongation at distal end of limb
– long metacarpals, walk on toes or hooves (increased leg length)
name the joint sequence of the forelimb
shoulder, elbow, carpal, metacarpophalangeal, interphalangeal (proximal, distal)
what kind of orientation does the scapula have?
vertocal
what does the scapula increase?
limb length, increase in stride stride length and more ground covered
what is the vestigal clavicle
muscular attachment between forelimb and trunk
describe the borderes of the lateral surface of the scapula?
- dorsal - palpable
- cranail - palpable
- caudal - diff to palpate
what runs along the body of the scapula
scapular spine
what surface of the scapula is the gleniod cavity on
ventral
describe the glenoid cavity
- concave
- smooth subchondral surface for shoulder joints with hyland cartilage covering it
Describe the medial surface of the scapula
- flat, scapular glide, faces the ribcage
T/F cats have more rounded cranial angle than dogs in terms of scapula
true
what type of bone is the humerous
long bone
Describe the proximal end of the humerus
Head
- articular surface, convex and smooth
Greater tubercle
- cranail to head
- location of shoulder joint
Lesser tubercle
- medial
intertubercular groove
- passage of bicep tendon
- smooth surafece
Describe the distal end of the humerus
- medial epicondyle
- lateral epicondyle
- trochlea - central depression
- ulnar foss and radial fossa meet at the supertrochlear foreman
T/F horses have a supertrochlear foreman
false
what rea the 5 centres of ossification in the humerus
- proximal epophyses
- body
- condyle - medial wpicondyle, meadail ahlf and lateral half
what are the components of the shoulder joint
- glenoid cavity of scapula - concace
- head of humerous - convex