Unit 1 - Tissue Flashcards
What are fibers in CT primarily made of?
Collagen or elastin
Differ in protein composition and density
Which CT is most abundant in the body?
Areolar
Where is areolar CT found?
Skin, mucous membranes, blood vessels, nerves, muscles, and stroma of many organs
What are the functions of areolar tissue?
Cushions, stretches, strength, nutrition to nearby cells due to its capillary network, area for immune system to work, attachment of skin to underlying tissues
Which CT tears easily?
Areolar
What is edema?
Excess extracellular fluid present
What is adipose CT made of?
Adipocytes and reticular fibers
Where is adipose tissue found?
Skin, heart, kidneys, yellow bone marrow, padding around joints, behind eyeball, body fat
What is the function of adipose?
Energy reserve (stores triglycerides)
Insulation
Support and protection (cushioning)
What is the appearance of adipose cells?
Large and rounded
Usually white, can be yellow
Blood vessels (highly vascularized)
Cytoplasm and nucleus pushed to the side of cell
What is brown fat?
Adipose CT that generates heat (normal fat insulates but does not generate )
Found in young and hibernating animals
Internal, not subcutaneous
None of the energy is used to convert to ATP, exclusively heat production
What is reticular CT composed of?
Only reticular fibers
Where is reticular CT found?
Only in organs (liver, spleen, lymph nodes) and basal lamina
What is the function of reticular CT?
Binds smooth muscle cells
Forms the framework (stroma) of many organs
What are the 3 loose CTs?
Areolar, adipose, reticular
What are the 3 dense CTs?
Dense regular, dense irregular, elastic
What is dense regular CT composed of?
Mostly fibroblasts in rows between bundles of collagen fibers arranged parallel
Where is dense regular CT found?
Tendons, ligaments, fascia, aponeuroses (attach muscle to muscle)
Why do injuries to tendons and ligaments heal slowly?
Dense regular CT has a poor blood supply
What is the function of dense regular CT?
Strong attachment from collagen bundles (but only in the direction the fibers run)
Still flexible
What is dense irregular CT composed of?
Same as regular (fibroblasts and collagen), but different arrangement
Collagen fibers woven in flat sheets, running in all directions
Form capsules around certain organs
Where is dense irregular CT found?
Skin, fascia, periosteum of bone, perichondrium of cartilage, joint capsules, heart valves, membrane capsules around various organs
What is the function of dense irregular CT?
Provides strength in all directions
Resists tearing
Flexible
What is elastic CT composed of?
Fibroblasts with few collagen fibers (stretchiest)
Can regain their shape
Can be arranged parallel or interwoven
Where is elastic CT found?
Anywhere that moves and can regain shape
Lungs, trachea, ligaments between vertebrae, vocal cords, arteries, suspensory ligament of penis, nuchal ligament in horses/cows, stomach and bladder wall
What is the function of elastic CT?
Allows stretching
What is the difference between tendons and ligaments?
Tendon: attaches muscle to bone, dense regular CT, strong
Ligament: attaches bone to bone, elastic CT, stretchy
What is cancer of epithelial cells?
Carcinoma
What is cancer of connective tissue cells?
Sarcoma
What is areolar CT composed of?
Loosely organized cells and extracellular substances :
Fibroblasts, macrophages, mast cells, adipocytes, plasma cells
Collagen, elastic, and reticular fibers
Semifluid ground substance
What is the stroma?
Reticular fibers + matrix
The supporting framework of organs
What are the 2 types of specialized CT?
Hemopoietic (red bone marrow)
Support (cartilage and bone adapted for weight bearing)
What are the characteristics of support tissues?
Solid, flexible, yet strong extracellular matrix
Cells contained in matrix cavities
External covering (periosteum/perichondrium) that can generate new tissue
What are cells contained in matrix cavities called?
Lacunae
What are the physical characteristics of cartilage?
Stiff, plastic matrix that has lubricating and weight-bearing abilities
Provides smooth surface for bones to articulate.
Found where support and movement are required (in joints and skeleton)
What are mature cartilage cells called?
Chondrocytes
What are the 3 types of cartilage?
Hyaline (joints), elastic (nose), fibrocartilage (disks)
What is the matrix of cartilage made of?
Glycosaminoglycans (chondroitin sulfate, hyaluronic acid, collagen, elastin fibers, fluid)
How does cartilage recieve nutrients?
Has no blood supply (also no nerves)
Uses diffusion from perichondrium, which limits its thickness (cells far away from nerve supply would die)
What is hyaline cartilage made of?
Chondrocytes in a bluish glossy ground substance (firm gel made of chondroitin sulfate and collagen)
Where is hyaline cartilage found?
Ends of long bones (articular), ends of ribs, parts of larynx, tracheal rings, bronchial tubes
Which type of cartilage is most abundant in the body?
Hyaline
What is the function of hyaline cartilage?
Allows smooth movement at the joints
Flexible and supportive
Which CT makes up most of the fetal skeleton?
Hyaline cartilage. Gradually replaced with bone during development
Which is the most rigid type of cartilage?
Hyaline
What is elastic cartilage composed of?
Chondrocytes, cartilage substance (matrix), and elastic fibers
Similar in structure to hyaline, but more elastic fibers
Where is elastic cartilage found?
Ears, auditory tubes, epiglottis
What is the function of elastic cartilage?
Gives support and maintains shape
Very flexible and elastic
What is fibrocartilage composed of?
Less chondrocytes, scattered around bundles of collagen in a cartilage matrix
No perichondrium
Where is fibrocartilage found?
Intervertebral discs, menisci of knee joint, pubic symphysis
What is the function of fibrocartilage?
Support and fusion
Cushions strategic joint ligaments and tendons
Adapted to absorb shock
What is cartilage composed of?
Chondrocytes in little spaces called lacunae embedded in a matrix of ground substance and fibers
What are the characteristics of bone?
Hard, strong, relatively lightweight.
Fiber framework that gives bones strength but not brittleness (slightly flexible)
Think of as the ‘concrete’ of the body
What is bone made of?
Inorganic (minerals - what makes the bone hard) and organic (collagen), blood vessels…
What is bone also known as?
Osseous tissue
Where is bone found?
Anywhere that needs protection and uses weight bearing
What is the function of bone?
Forms the frame and protection of vital organs
Provides a calcium reserve
Bone marrow stores fat and produces blood cells
What are the 2 types of bone?
Compact AHA cortical
Spongy AKA cancellous
Which type of bone is the outer layer?
Compact
Which bone type is in the inner area?
Spongy
What are the 3 types of bone cells?
Osteoblasts (make new bone)
Osteocytes (mature bone cell, in lacunae)
Osteoclasts (break down bone)
What is blood made of?
Formed elements (AKA blood cells) suspended in a liquid matrix (plasma)
Liquid specialized CT?
Blood
What are the 3 blood cells?
RBC (erythrocyte)
WBC (leukocyte)
Platelets (thrombocytes)
What is blood made of?
Matrix is plasma
Ground substance is water ……
Fiber is plasma proteins
What is the difference between plasma and serum?
Plasma is the fluid part of unclotted blood (contains clotting proteins)
Serum is what remains after a clot forms, like plasma but all clotting factors have been used up
What are membranes?
Thin sheets of tissue that line cavities, cover surfaces, or separate tissues/organs
Composed of either both epithelial AND connective, or just connective tissue
What are the 3 epithelial membranes?
Mucous
……
What are mucous membranes?
Line body cavities open to the exterior (ex. GIT)
Have goblet cells that create mucus
Provide lubrication and moistness
Sticky and has antibodies, traps and destroys invaders
What is mucus made of?
Water, electrolytes, and mucin (protein)
What are the layers of mucous membranes?
Either Stratified squamous, Pseudostratified, orSimple columnar
Loose connective tissue called lamina propia
CT called submucosa
What are the function of mucuous membranes?
What is the difference between mucous and mucus?
What are serous membranes?
Line internal body cavities and internal organs, not exposed to external
Help form mesenteries (supportive ligaments/membranes for organs like stomach and uterus)
What is the purpose of serous fluid?
Reduce friction during movement.
Fluid is transudate (thin, watery secretion with no electrolytes [no mucin])
……
What is serous fluid called during disease?
Ascites ….
What are the layers of serous mebranes?
Parietal (lines cavity wall)
Visceral (covers outer surface)
Simple squamous (very permeable)
What are cutaneous membranes?
Skin
Surface is dry, non-living cells.
What are the layers of cutaneous membranes?
Keratinized stratified squamous…..
What are CT membranes?
No epithelium attached, only connective tissue
What are the 4 CT membranes?
….
Synovial membranes (line joints, bursae, and tendon sheaths. Reduce friction in joint)
How does tissue heal and repair?
After injury tissue becomes inflamed
New tissue forms to heal (not scar tissue)
Remodelling: scar tissue forms
What are the 5 signs of inflammation? (PRISH)
Pain
Redness
Immobility
Swelling
Heat
What is the purpose of inflammation?
Body’s attempt to isolate the area, clean up the area, and prevent further damage (pain encourages careful movement)
Where can inflammation occur?
Anywhere in the body
What are the 3 stages of tissue healing?
- Inflammation
- Organization
- Regeneration
What are the 5 stages of inflammation?
- Vasoconstriction (constrict to limit blood loss), then after 5 minutes vasodilation (blood flow increases)
- Fluid causes swelling
- Clot formation (scab)
- Macrophages and neutrophils enter for cleanup (makes pus)
- Histamine and heparin levels drop, vasodilation (capillaries return to normal)
What happens during the organization stage of healing?
Bright pink granulation tissue (infection resistant tissue with lots of nutrients) forms under scab
Good thing in most cases except in horses who get ‘proud flesh’
What happens during the regeneration step of healing?
Epithelialization (epithelial tissue grows) occurs and granulation tissue is replaced by scar tissue
Scab falls off
Fibroblasts make collagen fibers -> replace granulation -> contract down (pull the edges together)
What is a scar made of?
Mainly collagen
- Can disappear with time as tissue remodels
When can scars cause issues?
- Cause problems if they form internally by constricting vital organs (eg. heart)
- Cause problems with adhesions
What are the classifications of healing?
First, Second, and Third Intention
What is first intention healing?
Has wound edges held in close apposition with minimal scarring
The collagen doesn’t have a big space to bridge
What is second intention healing?
Has healing wound edges separated
Granulation tissues forms across the gap, eventually replaced by epithelial tissue
Moderate scarring
What is third intention healing?
Large extensive wound
Severe scarring
Healing delay
