Final Exam 2 Flashcards
Tight junctions
Outer layers of the plasma membranes between two cells are fused
Creates a fluid tight seal
Prevent penetration and leakages
Important for the urinary bladder
Desmosomes
Anchoring junctions
Made of interlocking filaments
Filaments penetrate from the plaque into the cytoplasm to stabilize the bond
Important for areas with lots of stretching
Skin heart and uterus
Gap junctions
Communicating junctions
Fluid filled tunnels between the cells
Connexons: tubular channel proteins link adjoining cells
Allows rapid exchange of nutrients and ion change signals
Microvilli
Finger like projections
Non-motile
Bush border of the cell
Increases surface area for better absorption and secretion
Cilia
Thousands of hairlike structures
Motile: in a wave like motion
Helps move mucus and debris out of things like the trachea
Simple squamous epithelia
Single layer of cells
Scale like with irregular outlines
Thin
Reduces friction, filtration and nutrient exchange
Air sacs of lungs, lining blood vessels and heart, pleura/peritoneal/pericardial lining
Simple cuboidal epithelia
Single layer, cube shaped cells
Lining, secretion, absorption
No protection from abrasion
ovary, kidney tubules, pancreas
Simple columnar epithelia non ciliated
No cilia but has microvilli
Absorption, secretion and protection with goblet cells
Gastrointestinal tract
Simple columnar ciliated epithelia
Moves fluids or particles along passage ways by ciliary action
Uterine tubes, paranasal sinuses, spinal cord canal
Stratified squamous epithelia
Skin
Cuboidal/columnar at the basal layer
As the cells die and move up they become keratinized and squamous
Protection
Stratified cuboidal epithelia
Protection
Ducts of sweat glands, mammary glands, salivary glands
Stratified columnar epithelia
Protection and secretion from goblet cells
Rare: parts of urethra, pharynx
Pseudostratified columnar epithelia
All cells are attached to the basal layer but other some reach the surface
The nuclei are found at different levels and give the appearance of being stratified (actually simple)
Can be plain or ciliated
Often contain goblet cells
Upper respiratory tract or glandular ducts
Protection, secretion, movement of mucus by ciliary action
Transitional epithelia
Good in areas with lots of stretching like the urinary bladder
Start off as stratified and cuboidal/columnar and as they stretch they become squamous and simple
Permits distension without leakage
Holocrine secretion
Gland fills with secretory material and discharges entire cell contents
Completely destroys the cell
Merocrine secretion
Gland has vesicles which pass secretory material through the cell membrane without any significant loss of cytoplasm
Apocrine secretion
Secretory material gets pushed to the apex of the cell and the apex explodes releasing the secretion
Only some cytoplasm is lost
Steps of inflammation
1: very short lived vasoconstriction
2: histamine and heparin are released from mast cells and causes vasodilation this causes redness and swelling and brings nutrients to the area
3: fluid enters the area and furthers swelling and irritates the nerve
4: a clot forms and a net of fibrin forms to trap bacteria and isolate the site, if it is on the skin it is called a scab which protects and covers the wound
5: macrophages and neutrophils enter the area and clear debris and bacteria and these quickly die to form pus
6: histamine and heparin levels drop and the swelling and redness settles down
First intention wound healing
Wound edges are close in apposition and results in minimal scarring
Second intention wound healing
Wound edges separated and granulation tissue forms over the gap and a moderate scar forms
Third intention wound healing
Large extensive wound gap with severe scarring and delayed healing
Osteoblasts
Form bone
Adds Minerals to ossify
Metabolically active
Osteocytes
Osteoblasts that have been trapped in lacunae of ossified matrix
Can convert to osteoblasts when needed (injury)
Less metabolically active than osteoblasts
Osteoclasts
Cells that eat away or remove bone
Important for remodelling and growth
Allows body to withdraw calcium from bone
Osteon or haversian system
Functional unit of compact bone
Nutrient foramina
Large channel through which arteries, veins, and nerves penetrate to feed the bone marrow
Endochondral bone formation
Bone grows into and replaces cartilage framework
Intramembranous bone formation
Bone develops from fibrous tissue membranes
Fibrous tissue membranes cover the brain of the fetus and as it matures these membranes are ossified
Calcitonin
Decreases blood calcium levels
Inhibits the release of calcium from bones
Spina Bifida
A cleft or space in the dorsal part of the vertebral column
Hemi vertebrae
Failure if the vertebral body to ossify resulting in an improperly formed or shaped vertebrae
Wobblers
Cervical intervertebral instability
Narrowing of the spinal canal and compresses the spinal cord
Common in dobermans, Great Danes and horses
Luxation
Dislocation
Intervertebral disc disease
Degeneration of the intervertebral discs
Fracture healing
Fracture hematoma forms
Osteoblasts invade area and start to form in a callus
Calcium salts are deposited to ossify the callus
Initial healing complete
Slow twitch fibers
Slower to contract
Sustained contractions for longer
Aerobic
More mitochondria and myoglobin
Fast twitch fibers
Fast contractions
Fatigue easily
Short bursts of contractions
Powered by ATP and not much oxygen
Smooth muscle
Involuntary Nonstriated Single nuclei Unbranched Nerve supply is not needed for visceral muscle but is needed for multi unit muscle
Cardiac muscle
Involuntary Striated Single nuclei Branched Nerve supple needed to contract
Skeletal muscle
Voluntary Striated Multinucleated Unbranched Nerve supply needed for contraction
Order of the layers of the heart from most outer layer to most inner layer
1: fibrous pericardium
2: parietal pericardium
3: pericardial space
4: visceral pericardium/epicardium
5: myocardium
6: endocardium
S1
Atrioventricular valves closing during ventricular contraction
“Lub”
S2
“Dub”
Closing of the semilunar valves at the end of systole
S3
Passive filling of the ventricles
S4
Atrial contraction
Tetralogy of fallout
Pulmonic stenosis
Interventricular septal defect
Malpositioning of the aorta
Ventricular hypertrophy
Murmurs
Abnormal heart sounds
Arrhythmias
Abnormal rhythms or rates
Left sided heart failure
Congestive heart failure
Back pressure increases at the end of Pulmonary capillaries and forced fluid out causing edema
Lung congestion
Right sided heart failure
Fluid backs up into the abdomen/venacaves Jugular veins engorged Ascites: fluid build up in abdomen Hydrothorax: fluid build up in chest Subcutaneous edema
Route for passing a stomach tube
Ventral nasal meatus
Surfactant
Chemical that reduces the “stickiness” of the alveolar walls and assists in expansion during breathing and prevents lung collapse
Pneumothorax
Air leaks into the space between the lung and thoracic wall
Keratinocyte
Gives resiliency and strength Waterproofs the skin Majority of cells Produced at the basal layer As cells move up from basal layer, it dies and become keratinized Sloughed off at the surface (shed)
Epidermis
Outermost layer of skin
No blood vessels
Melanocyte
Less common
Found on basal layer
Produces melanin pigment
Protects against UV light
Langerhan cells
Type of macrophage
Phagocytizes micro-invaders
Merkel cells
In the basal layer
Associated with sensory nerve endings
5 layers of hairless epidermis
1: stratum corneum (cornified)
2: stratum lucidum (clear)
3: stratum granulosum (granular layer)
4: stratum spinosum (spiny layer)
5: stratum germinativum (basal layer)
3 layers of hairy epidermis
1: stratum corneum
2: stratum spinosum
3: stratum basale
Has folds of skins which hair grows out of
Epidermal papillae: where tactile hairs grow from
Dermis
Tough layer
Highly fibrous: dense irregular connective tissue (collagen runs is different directions) (very strong)
Has: hair follicles, nerve endings, glands, smooth muscle, blood vessels, lymphatic channels
2 layers of the dermis
Papillary layer: thin superficial layer
Nerve endings
Reticular layer: majority of the dermis
Hypodermis
Subcutaneous layer
Primarily adipose tissue
Thick layer below the dermis
Contains pacinian corpuscles: special touch receptor for heavy pressure
Allows skin to move freely over underlying structures
Two basic types of of melanin
Black and orange
Shading and darkness depends on
How much melanin is present
Albinos produce
No melanin
Paw pads
Thick layer of fat and connective tissue covered by thick epithelium
Paw pads functions
Shock absorbers
Insulation
Protection
Thickest and toughest skin on the body (has all 5 layers)
Paw pads
Do paw pads have exocrine glands
Yes, this is where most animals sweat from
Except for horses
Chestnuts
Dark horny structure in the medial aspect of the carpus/tarsus
Ergots
Dark horny structure buried in the caudal hairs of the fetlock joint (distal to chestnuts)
Plenum nasale/nasolabiale
Skin around the nose Thickened epithelium Extends to lips in large animals Aglandular in small animals Glandular in sheep and cattle
If sick cows stop licking their nose
Cows lick to keep their nose clean
If they stop licking (and mucus is present) it can indicate the cow is sick
Clear mucus: not upper respiratory infection
Yellow/green mucus: possible upper respiratory infection
Cutaneous pouches in sheep
Infoldings of skin that contain hair, sebaceous and oils glands
Three locations: infraorbital, interdigital, inguinal
Fatty Yellow secretion dries and sticks to skin (smelly)
PRISH
Pain Redness Immobility Swelling Heat
How do food allergies often manifest in dogs and cats
Skin problems
Ear problems
Anal sac disease
Cats may develop this from skin problems
Compulsive grooming behaviours leading to alopecia
Functions of hair
Traps air for insulation
Dark colors absorb heat from light
Protection via camouflage
3 parts of hair
Shaft: part visible above the skin
Root: part below the skin
Follicle: infolding of the epidermis into the dermis/hypodermis
3 layers of the hair shaft
Medulla: core of the hair
Cortex: hard keratin (thickest layer)
Cuticle: thin layer of cells on the surface of the hair arranged in shingle-like layers
Hair bulb
Deepest part of the hair follicle
Papilla
Mound of dermal cells at the base of the bulb
Matrix of hair
Rapidly dividing epithelial cells covering the papilla
Nourished by vessels below it
As the cells divide, they push older ones up and they become keratinized and die and then become hair
Root hair plexus
Web of sensory nerve endings around the root of hair
Makes hair sensitive to touch (tactile hairs)
Not every hair has a sensory nerve
Compound hair follicle
Multiple strands of hair, each with its own follicle, can emerge from a single pore
Three stages of hair growth
Anagen: growth
Catagen: transition
Telogen: resting/shedding
During telogen (shedding)
The hair bulb separates from the dermis
Hair falls out or is pushed out when the new hair starts to grow
Telogen effluvium
Shedding
When does shedding occur
Seasonally (photoperiod)
Disease
Hormonal changes (parturition)
Hair color
Is in the cortex and medulla of hair strand
Melanin produced at the base of the hair follicle
Different pigmentation depends on
Quantity of melanin
Type of melanin (orange, black/brown)
no melanin (white)
Age (decreases with age)
Primary hairs
Straight or arched
Thicker and longer
Come to the surface of the coat
Guard hairs
Secondary hairs
Softer and shorter than guard hairs
“Undercoat”
Compound hair follicles: long primary hairs surrounded by secondary hairs
Wool is an example
Describe wool
Often waxy due to lanolin
Lanolin is water proofing and used in skin ointments
Tactile hairs
Sinus hairs or whiskers
Mixed intermediately throughout the hair coat (adds sensation)
Follicle is Highly innervated
Arrector pili muscle
Small, smooth muscle
Attached to hair follicles
Innervated by the sympathetic nervous system (autonomic)
Contraction pulls the hair erect
Used for warmth to trap air, and to make animal look bigger when threatened
Sudoriferous glands
Sweat glands
Produces a watery transparent liquid
Helps cool the body through evaporation
Two types of sudoriferous glands
Eccrine: empty onto the surface of the skin (Merocrine and Holocrine)
Apocrine: empty onto the hair follicle
Sebaceous glands
Oily secretion
In the dermis
Empties onto the skin or into hair follicle
Produce sebum: oily lipid substance
Ear canal (eat wax), lips, labia, penis, prepuce, anus, eyelid
Sebum functions
Traps moisture Keeps skin and hair soft Waterproofing Reduces risk of infection Production is hormone sensitive (increases at puberty)
Acne or white/black heads
Sebum binds dead skin cells
Blocks duct openings
Ducts swell and may rupture
Sebaceous cysts: duct is often destroyed
Tail and chin glands
Dogs and cats have large sebaceous glands at the dorsal base of the tails
Hairs are coarse and oily here
Assists animal in identification (smelly)
Most noticeable in cats (called stud tail)
Anal sacs
Reservoir for malodorous secretions
Lined with sebaceous and apocrine glands
On the Lateral margins of the anus
Expressed at: defecation (territory marking) and when the animal is frightened
Anal sac disease
Anal sacs become impacted or infected
Results in: scooting, pain/discomfort, licking and biting area, painful defecation, can rupture
Can be a sign of allergies
Treatment: expression, removal, disinfecting
Onychectomy
Claw amputation/removal
Dewclaws
Remnants of the first digit
Cows pigs and sheep have both medial and lateral dewclaws (2 and 5 digit)
Pigs’ dewclaws have bone (ruminants don’t)
Hoof wall
Divided into toe, quarters, and heel region
Thickest at the toe and thinnest at the heel
Horn tubes: tiny vertical lines running from coronary band to the ground
Rings around the hoof represent different periods of growth
Grows continuously from corium of the coronary band down
Expand as weight is put on the hoof
Corium
Modified dermis Tissue underlying the hoof is sensitive and vascular Divided into: Coronary band Corium Perioplic Corium (layer below the coronary band like the cuticle on a nail) Laminar (wall) Corium Sole Corium Frog Corium
Periople or perioplic corium
Region 2-3cm at proximal border of the hoof
Epidermal cells here produce the external layer of the hoof wall
Coronet or coronary Corium
Distal and deep to perioplic Corium
Cells here produce the middle layer of the hoof wall Thick tough, weight bearing
Hoof grows from the coronary band
How does the Corium and hoof wall attach to each other
Hoof and Corium form laminae which interlock
Permit the wall to grow while allowing movement
Non sensitive
Sole
Bottom (plantar) surface of the hoof Concave Not primary weight bearing surface No nerve superficially Protects from injury Made of keratin
White line
Indicates the junction of the sole and hoof wall
Frog
Triangular shaped structure Central and collateral sulcus Cushions at the heel of the foot Reduces slipping Mechanically pumps blood back up from the leg
Digital cushion
Thick pad of fat and fibrous tissue below the frog
Laminitis (founder)
Inflammation of the laminae attaching the hoof wall to the Corium
Most common cause: dietary (sudden increase in grain or rapidly growing fresh spring grass)
Results in a bacterial overgrowth and fermentation in the large intestine
The toxins produced create inflammation of the hoof wall and compresses vessels
Coffin bone may rotate or sink within the hoof, can even penetrate the sole
Signs of founder disease
Front feet are often affected worse
Horse stands with front legs extended and hind legs under the body
If all feet are affected than the horse will stand with all its feel tucked under a hunched body
Or horse will lie down a lot
Sunken in sole, or penetrating coffin bone
Hooves are warm to the touch
Hoof wall curls up at toe
Treatment of founders
Pain relief and anti inflammatory meds Ice (enzymes that breakdown the laminae are temperature sensitive) Minimal exercise Shoeing, trimming Feed management
Prevention of founder
Limit high CHO feeds like grain, molasses and corn
Monitor feet and treat at first signs
Sand cracks
VERTICAL Cracks in the hoof wall
Named for region of occurrence
Often painless but can be painful if they are full thickness
Causes:
Improper trimming (beginning at solar border)
Defect in hoof formation (beginning at coronary band)
Excessive drying of the hoof
Thrush
Degenerative condition of the frog
Associated with a build up of microorganisms in the sulci
Black necrotic foul smelling material in affected area
Contracted foot/heels
Foot is narrower than normal Can be caused by lack of frog pressure or from being improperly shoed Front feet more commonly affected Can cause lameness known as hoof bound Reduces frog size
Navicular disease
Chronic degenerative condition of the navicular bone
Begins with loss of cartilage and inflammation of bursa between the navicular bone and tendons
Heel pain and lameness
Common in race horses
Causes:
Trauma from landing and sudden weight bearing during racing
Defective shoeing
Bruised sole
Direct injury from stones or irregular ground or trauma
Poor shoeing
Can cause lameness
Interdigital dermatitis/Slurry heel
Bacterial degeneration of the heel
Disease of cattle From the bacteria found in liquid manure (slurry)
Not usually painful
Treated with topical disinfectants
Foot rot/interdigital necrobacillosis
Proliferation inflammation (necrotizing) of interdigital space, coronary region and P3
Caused by microorganisms (same as thrush)
Signs: foul smell, redness, swelling, discharge from damaged interdigital skin, lameness
Very responsive to antibiotics
Interdigital fibroma (corns) (bovine)
Proliferation of the tissue of the interdigital cleft
Associated with foot rot and interdigital dermatitis
Mass of connective tissue projecting down between the claws
Walking becomes painful as the corns grow
Can become ulcerated and cause lameness
Overgrown hoof
Long hoof wall, usually lateral claw
The lateral wall curls under the sole
Toe gets excessively long
Hoof wall fissures (bovine)
Vertical or horizontal
If found in one claw, corresponding claw on opposite foot should be checked
Vertical fissures: (sand cracks) usually from overgrown hooves resulting in abnormal weight bearing
Horizontal fissures: (thimbling) usually occurs in mature dairy cows following laminitis
Laminitis (founder) in bovine
Inflammation and damage to the tissue between the hoof and coffin bone
Most foot lameness of cattle is directly or indirectly related to laminitis
Major cause: ingestion of excessive amounts of grain
Damages coronary band (doesn’t grow properly)
Ulceration of the sole
More prevalent in dairy cattle in confined quarters
Front feet of bulls and rear feet of cows
Signs: lameness and areas where horn is lost
Syndactyly (mule foot)
Partial or complete fusion of digits 1 or more feet at birth
Ex. Bovine have 2 claws but it is born with only 1
Horns
Bone covered with epidermis
Keratin tubules bound to periosteum of underlying bony core
Starts as epithelial horn bud and grows out as a solid structure that become hollow
Hollow because of the sinus cavity
Male and females can have horns
Grow continuously
Only species that shed horns annually
Pronghorned antelope
Polled
Bred to have NO horns but can have remnants
Non-polled
Bred to have horns
Antlers
Only in males
Shed annually
Bony growth that is nourished by velvet on the outside
Once grown, a connective tissue ring forms like a tourniquet around the base and causes velvet to fall off
Antler hardens
Late fall/winter the bony base weakness and antlers fall off
Systolic pressure
Maximum pressure in the arteries during ventricular contraction
Diastolic pressure
Minimum pressure in the arteries during ventricular relaxation
Pulse pressure
Difference between the diastolic and systolic pressures
When the arteries stretch and recoil to normal size
Peripheral or systemic resistance
Friction in the arteries that limits the flow of blood
Contractility
Ability of the heart to fully contract
After load
The force the ventricles need to overcome to push blood forward
Preload
The amount of blood in the heart before contracting or the amount of blood the ventricles receive from the atria
Cardiac output
The volume of blood the heart is able to pump forward in one minutes
Stroke volume x heart rate
Starlings principle
A larger preload means there is a higher contractility
Heart rate
Number of beats per minute
Cardiac output is affected by
Preload
Contractility
After load
Heart rate
Shock is defined as
Failure of tissue perfusion
Automaticity of the heart
Innate ability of the cardiac muscle fibers to contract at a certain rhythm without external stimulation
The order of the conduction system in the heart
Sinoatrial node in the right atrium Atrioventricular node Bundle of His Right and left bundle branches Purkinje fibers
Hilus of the lung
A small area on the medial side of each lung where air, blood, lymph and nerves enter and leave the lung
If a piece of a newborns lung floats what does this mean
The animal was born alive
If a piece of a newborns lung sinks what does this mean
It was born dead
Functions of the skin
Covers and protects Prevent desiccation Excretes water, salt and wastes Receives and converts sensory info Vitamin d synthesis Acts as a barrier (most important) Maintenance of body temperature
Osteochondrosis dessecans
Abnormally thickened articular cartilage
A piece can be torn off and float freely in the joint
Hereditary
Giant and large breed dogs and horses
Loose connective tissue
Most common
Skin layer and stroma of organs
Cushioning, strength, elastic and flexible, support, capillary network, attachment of skin to underlying tissues
Adipose tissue
Skin around the heart, kidneys, padding on joints
Energy reserve, insulation, support, protection
Highly vascularized
Appears yellow due to fat soluble carotenoids
Brown fat
Special fat that generates heat in hibernating animals
Reticular fat
Binds smooth muscle cells and is the frame work for some organs
Dense regular connective tissue
strong attachment between structures
Poor blood supply
Heals slowly
Tendons, ligaments, fascia aponeuroses
Dense irregular connective tissue
Strength, resists tearing but is flexible
Skin (dermis is mostly dense irregular)
Flat sheets with fibers running in all directions
Elastic connective tissue
Stretching
Lungs, trachea, bronchial tubes
Hematopoietic connective tissue
Red bone marrow
RBC production
Support tissue connective tissue
Cartilage and bone
Made for weight bearing
Hyaline cartilage
Most abundant in the body
Ends of the ribs, nose, larynx, trachea rings, makes up most of the fetal skeleton and growth plates
Allows movement at joints, flexibility, support
Elastic cartilage
More elastic than hyalin cartilage
Very flexible and maintains shape
External ear and epiglottis
Fibrocartilage
Support, fusion, cushioning, absorbs shock
Intervertebral discs, menisci, patella, pubic symphysis
Plasma
Unclotted
Has clotting proteins
Serum
Clotted
No clotting proteins
Goblet cells
The only unicellular exocrine cell that does NOT have a duct
Why is skeletal muscle striated under a microscope?
Because light can go through actin and NOT myosin
Neuromuscular junction
Where the motor nerve links to the muscle fiber (synaptic cleft)
Calcium triggers the release of what to start a contraction
Acetylcholine
Acetylcholine binds to receptors in the sarcolemma and initiates what
Sodium channels to open
Sodium channels create a what
Depolarizing wave
