Anat and Phys

exam 2

Define tissue

Groups of cells that are similar in structure and perform a common or related function

4 basic types of tissue

epithelial, muscle, nervous, and connective

Main function of epithelial tissue

Strong regeneration ability and will replace lost cells. These cells are inverted, but avascular, so nutrients are delivered through the basement membrane.

What are the two surfaces of epithelial tissue?

Apical and basal membranes

Define apical membrane

Upper area exposed to the environment or the cavity lining of internal organs. Surface may be smooth but usually microvilli are present.

Define basal membrane

Bottom surface. Connected to the basement membrane.

What is the basement membrane

Gives support and structure to epithelial cells. Made up of reticular and basal lamina. Acts as nutrients for epithelial cells since they are avascular.

Define reticular lamina

CT network of collagen proteins that support epithelium cells.

Define basal lamina

Non cellular adhesive sheet of glycoproteins secreted by the epithelium cells that serves as a selective filter and support structure.

Where are simple cells found

A single layer of single epithelial cells-inside the body

Where are stratified cells found

Multiple layers of epithelial cells-outside the body

Where are squamous cells found

Lungs, blood vessels, and skin

Where are cuboidal cells found

Kidneys/glands

Where are columnar cells found

Intestines

Name the types of epithelial cells

Simple squamous, simple columnar, simple cuboidal, pseudostratified columnar, stratified squamous-keratinized, stratified squamous- non-keratinized.

Define simple squamous

Relatively flat cells that line surfaces, may be further broken down into; endothelium, slick friction - reducing cells that line blood and lymph vessels. Mesothelium, found on serous membranes that line organs and body cavities

Define simple columnar

Line digestive tract from stomach through rectum. They function in absorption and secretion, two modifications, dense microvilli (brush border, increases surface area for absorption)

Define simple cuboidal

These cells function in absorption and secretion. They are rare in the body, forming walls of smallest ducts and many kidney tubules. 

Define pseudostratified columnar

Ciliated version containing goblet cells line the respiratory tract. They function in mucous secretion to help trap pathogens and excretion. 

Define stratified squamous keratinized

Thick layer of cells used for protection. Surface cells are constantly being replaced. Found on the external parts of skin and extend into every body opening. External skin is 4-5 of dead, keratinized skin cells.

Define stratified squamous non-keratinized

Internal skin surface is alive, wet/slick, and acts as a mucosal membrane. 

What are the two types of glands and their main difference

Exocrine and endocrine. Their ducts are their main difference.

Define exocrine gland

Secrete their product onto body surfaces or into body cavities. Excrete via epithelium lined ducts. Some exocrine glands are; mucous, sweat, salivary, liver, pancreas. 

Define endocrine gland

Ductless glands. Produce hormones. Excreted by exocytosis into intercellular space from there hormones travel via lymph or blood to target tissue. Pituitary 

4 main types of connective tissue

Connective tissue proper, cartilage, bone, and blood

Main functions of connective tissue

Binding and support, protection, insulation, and transportation of substances

3 main components of connective tissue

Ground substance, cells, and fibers

Why are glycosaminoglycans (GAG) so important?

GAG intertwines and traps water. This helps produce synovial fluid, but it cushions and lubricates joints. Ex: hyaluronic acid and glycosamine

3 types of fibers in connective tissue

Elastic, collagen, and reticular

Define elastic fiber

Certain connective tissues secrete Elastin, this is a rubber-like protein found where elasticity is needed, these will return to their original shape after being stretched or compressed (skin, lungs, blood vessel walls).

Define collagen fiber

Secretes a fibrous tissue called collagen, these proteins bind together to create a very dense high tensile strength matrix, Long white fibers that are very flexible and provide great tensile strength and resist stretching.

Define reticular fiber

Short and fine collagen fibers that are arranged in branching patterns, form a delicate network around vessels to offer support and within organs such as the liver, spleen and lymph nodes where they provide structural support

Mature cells of connective tissue proper?

Fibrocyte

Productive cells of connective tissue proper?

Fibroblast

3 categories of loose connective tissue

Areolar, reticular, and adipose

Define areolar

Honeycomb or web-like network of loose fibers that contains ground substance, a thick viscous fluid that surrounds cells. It is found in-between muscle fibers.

Define adipose

Chicken wire appearance. Cells filled with oil droplets (adipocytes). Takes up and releases fat. Brown adipose tissue contains many mitochondria. Adipose tissue contains a large number of capillaries for rapid storage and mobilization of lipids. Found in fat tissue

Define reticular-loose connective tissue

Forms a stroma or mesh-like supportive structure for many free blood cells. Found around blood cells. Ex: lymph nodes, spleen, liver

Most common type of loose connective tissue?

Areolar

Define dense regular-loose connective tissue

All run the same direction. Strength is in the direction that they run. Ex: tendons or ligaments. Tendons- strong and bendable connections.mLigaments-some elastic fiber

Define dense irregular-loose connective tissue

Found in the scalar of the eyes and fibrous joint capsules. Thick, irregularly arranged collagen fibers. Found where tension from all directions may occur- multiple directions.

What is unique to cartilage?

Cartilage is avascular, aneural and 80% water.

3 types of cartilage

Hyaline, elastic, and fibrous

Define hyaline cartilage

Covers the ends of long bones. Provides a springy pad that absorbs compression at the end of joints – not radial dense will not show up on ultrasound. Lots of collagen fibers.

Define elastic cartilage

Forms the skeleton of the ear and epiglottis. Just like hyaline, but contains more elastic fibers.

Define fibrous cartilage

Structural intermediate between hyaline cartilage and dense regular CT. Found where support and ability to withstand heavy pressure is needed- Intervertebral disc and menisci. If the hyaline cartilage is damaged in an adult, fibrous cartilage will act as a repair. 

What type of cartilage is most common?

Hyaline

Mature cells of cartilage?

Chondrocyte

Productive cells of cartilage?

Chondroblast

Definition of a joint or articulation

A form of connection between bones. They provide stability to the skeletal system as well as allowing for specialized movement.

Inflammation of the joints is defined as?

Arthritis

6 types of joints?

Ball and socket, ellipsoid, plane/gliding, saddle, hinge, and pivot.

Function of synovial fluid?

Mainly lubricate the joint. But also, supplies nutrients to the hyaline cartilage, removes waste products. Synoviocytes are the main source of glycosaminoglycans in the synovial fluid

What are the cells of the bone?

Osteon, osteoclast, osteoblast, and osteocyte

Define osteon

Closely packed structural unit of bone that contains; lamellae, collagen fibers, VAN

Define osteoclast

Bone destroying, hydrochloric acid liberates the calcium

Define osteoblast

The primary bone cell that produce organic bone matrix of collagen fibers. Young bone cell

Define osteocyte

Mature bone cell

Define osteoid

Uncalcified bone. What osteoblasts lay down prior to calcification of the bone. 

Functions of the bone

Support, protection, movement, mineral storage, and blood cell formation.

Label the osteon

Haversion canal, Volksman canal, periosteum, circumferential lamellae, blood vessels, spongy bones, osteon

Define compact bone

The dense outer layer that looks smooth to the eye

Define spongy bone

Trabeculae honeycomb like structure found inside the long bone this is filled with red or yellow bone marrow 

Define periosteum

Heavily supplied with nerve, lymph and blood. Enter diaphysis through nutrient foramen. Perforating (sharpey’s) fibers are collagen tuffs that secures periosteum to bone. Double layer membrane covering the bone

Outer layer is dense irregular CT

Inner osteogenic next to the bone contains bone forming (Osteoblasts), and bone destroying osteoclasts.

Define endosteum

Delicate CT membrane that covers the trabeculae of spongy bone and lines the compact bone canals. Contains both osteoblasts and osteoclasts 

How are bones classified?

By location (axial or appendicular) and shape.

Define axial skeleton

Skull, ribs, vertebral column

Define appendicular skeleton

Upper and lower limbs, pelvis, scapula

4 shapes of bone

Long, short, flat, irregular

Define long bone

longer than they are wide, shaft (diaphysis) plus two ends (epiphysis), named for their elongated shape not oval size 

Ex: femur, humerus

Define short bone

Cube type bones. Ex: sesamoid, knees, hock

Define flat bone

Thin, flattened, small curve. Ex: Scapula, sternum, ribs

Define irregular bone

All other types. Ex: pelvis, hips, vertebrae

Label part of the bone

diaphysis, metaphysis, epiphysis

Define diaphysis

Shaft of bone, thick compact that surrounds a central medullary cavity, in adults the medullary cavity contains fat and is called the yellow bone marrow cavity 

Define metaphysis

Portion of the bone between the epiphysis and diaphysis, in young growing animals it contains the epiphyseal plate (growth plate)

Define epiphysis

Bone ends, these tend to expand, exterior surface = compact bone, interior surface = spongy bone. Joint surfaces covered with hyaline cartilage, between diaphysis and epiphysis is the epiphyseal line (remnant of epiphyseal plate).

Define growth plate

The growth plate also known as the epiphyseal plate, is a disc of hyaline cartilage that grows during youth to lengthen the bone.

What hormones affect bone growth?

Growth hormone (GH) - anterior pituitary (most important stimulus of epiphyseal growth), thyroid hormone (modulates GH), sex hormones (estrogen and testosterone) 1st increase growth rate, then induce epiphyseal plate closure.

How do hormones affect bone growth?

If messed with, such as spay/neuter before puberty, the animal will grow taller than expected due to a lack of sex hormones to induce growth plate closure.

How are fractures classified?

Position of bone ends after fracture: displaced (not lined up) or non-displaced (lined up)

Completeness: complete or incomplete

Orientation relative to long axis: linear, transverse, or oblique Skin penetration: open or closed

8 common fracture types

\
Comminuted- more than three pieces

Compression- the bone is crushed from impact, common in vertebrae

Spiral- occurs when excessive torque is placed on the bone Epiphysis- fractures involving the epiphyseal plate I-V. SALTER Harris

Depressed- depression of piece of skull from blunt force

Greenstick or Incomplete- happens in young soft bone in which the bone bends but does not completely break (calf and cattle guard)

Impaction- occurs when one piece of bone is forced down the center of the opposing piece (telescope)

Avulsion- piece of bone that is connected to a tendon/ligament which is torn off the main bone

Treatment of fractures

Open Reduction- surgically open the fracture to visualize the repair (can be done with intramedullary pin, plates, screws, nails, wire) 

Closed Reduction- this is done without opening the fracture site (can be done with a splint, cast, cross pins) 

Steps of fracture repair (treated or not)

Hematoma Formation (first 24 hours, very vascular) 

Fibrocartilaginous callus formation (7 days)

Bony callus formation (up to 8 weeks)

Bone remodeling (in response to stress, Wolf's Law, remodels the bone as close to how it was before, up to 6 months)

Define osteomalacia/rickett’s

“Rubber Bones,” lack of calcification of the bones, Ca and/ or Vitamin D deficient 

Define osteoporosis

Osteoclast activity out paces Osteoblast activity (breaking down bone quicker than it is laid down), diet related, hormone imbalances, vitamin D deficiency 

What are biphosphonates?

Treats osteoporosis by inhibiting osteoclast activity. 

Tiludronate disodium - Tildren- not usda approved

Clodronate disodium - Osphos- usda approved for only horses

SALTER Harris

For epiphyseal plate fracture

S- slip

A- above

L- beLow

TE- Trough Everything

R- cRushed

Hormone control of bone remodeling

Parathyroid hormone made in the parathyroid gland. Calcitonin produced by the parafollicular cells in the thyroid gland.

Decreased blood calcium levels will cause the release of parathyroid hormone which will activate osteoclast activity.

Increased blood calcium levels will turn off parathyroid hormone and release calcitonin which will inhibit bone reabsorption and encourage hydroxyapatite (inorganic portion of bone) deposition.

List ***four*** functions of epithelial tissue and where they occur. 

Protection- Skin

Absorption- Gut

Filtration- Kidney

Excretion- Kidney 

All epithelial tissue comes in three basic shapes: 1.) __*2.) ---- 3.)*__ ________ each of these shapes can be represented as simple, stratified or pseudostratified.

Cuboidal, Squamous, Columnar

The epithelial cells that line the inside of the mouth and the esophagus are __**____**__whereas __**_____**__ make up the cells of the external skin.

stratified squamous non-keratinized and stratified squamous keratinized

__ cells line hollow urinary organs and are unique because they allow bladder to __ from a 6 cell thickness to a __ cell thickness.

Transitional, expand, 3

__**___**__ cells line the respiratory tract. They contain __**___**__ cells which produce mucus.

Pseudostratified columnar, goblet

__**___**__ cells can be found lining the digestive tract and have __**_____**__ which help with absorption. 

Simple columnar and cilia/microvilli

 Glands, which are lines with epithelial tissue, come in two forms. Mucous glands are examples of __**___**__ glands, which excrete their product via __**__.**__

Exocrine and ducts

The adrenal gland is an example of an ____ gland which secretes its hormone product by __**____**__ into the blood. 

Endocrine and exocytosis

The fibrocyte is the mature cell for __**_____**__

Connective tissue proper

Where do chondrocytes get their nutrients from and why?

They get their nutrients from synovial fluid because they are avascular

What is the most common type of cartilage found in the body? What does it look like? Where is it found? If it is damaged, how is it repaired? 

Most common: Hyaline

It looks like a smooth, glossy surface. 

It is found on the ends of long bones within articular joints with collagen fibers. 

If  it is damaged, it will turn into fibrocartilage