Anatomy Flashcards
Extracellular matrix
A substance produced by the cells of a specific tissue and can contain protein fibers, salt, water and dissolved macromolecules
Located outside of cells
Epithelial tissue
- Covers the body’s outer surface and lines it’s internal cavities
- organs are lined on the outside and inside by epithelial tissue
- the majority of glands are derived from epithelial tissue
- epithelial tissues posses little to no Extracellular matrix.
Connective tissue
Binds and support the body’s organs
Muscle tissue
Enable movement
Nervous tissue
Enables communication among the body’s organs
Characteristic of epithilial tissue
Cellularity Polarity Attachment Avascularity Innervation Regeneration
Cellularity
Composed entirely of cells with little Extracellular matrix
Cells are bound together by several types of intercellular junctions
Polarity
Epithelial cells have an apical(top or exposed) surface and a basal surface where they attach to underlying cells
Attachment
Basal surface is attached to a thin basement membrane, which is an acellular structure produced by both epithelial and underlying connective tissue cells
Avascularity
All epithelial tissue lack blood vessels, the cell receive their nutrients by diffusion from underlying tissue
Innervation
Epithilia are richly innervated to detect changes in environment at a body organ region
Regeneration
Because apical surface is constantly exposed to the environment, epithelial cells are frequently damaged or die, they are replaced as quickly as they are lost.
Functions of epithelial tissue
Physical protection
Selective permeability
Secretions
Sensations
Physical protection
From dehydration and abrasion; and physical, chemical, and biological agents.
Selective permeability
Regulates the passage of certain molecules in or out of a certain region of the body.
Secretions
Some epithelial cells called exocrine cells produce secretions such as sweat or oil.
Sensation
Posses nerve endings that can detect light, taste, sound, smell, and hearing.
Basement membrane
- A specialized structure of epithelium
- found between the epithelium and underlying connective tissue
- provides physical support and anchoring of epithelial tissue
- acts as a barrier to regulate passage of large molecules between epithelium and underlying connective tissue.
Epithelial cell layers
- simple epithelium
- stratified epithelium
- pseudo stratified epithelium
Simple epithelium
A single layer of cells with all cells having an apical surface and attached to the basement membrane.
Stratified epithelium
- Two or more layers of cells
- not all cells have an apical surface nor do all cells attach to the basement membrane.
Pseudostartified epithelium
-single layer but not all cells reach the apical surface and their nuclei give the appearance of multilayered, stratified epithelium.. But they are not
Epithelial cell shapes
- squamous
- cuboidal
- columnar
Squamous
Flattened and similar to the shape of a fried egg.
Cuboidal
About the same size on all sides, the nucleus is usually centrally located.
Columnar
Taller than they are wide and nucleus is oval and located in the basal region of the cell.
Simple squamous epithelium structure
Single later of flat cells
Simple squamous epithelium function
Rapid diffusion and some secretion in serous membranes
Simple squamous epithelium location
- lining of alveoli of lungs
- lining of blood vessels-called “endothelium”-only component of walls of capillaries
- lining of heart-called “endocardium”
- serous membranes of body cavities
Simple cuboidal epithelium structure
Single layer of cube shaped cells
Simple cuboidal epithelium function
Absorption and secretion
Simple cuboidal epithelium location
Thyroid gland follicles, kidney tubules, ducts and secretory regions of most glands
Simple columnar epithelium structure
Single layer of cells that are taller than they are wide, oval shaped nucleus near base of cell, apical regions have microvilli, may contain goblet cells that secrete mucin
Simple columnar epithelium function
Absorption and secretion, secretion of mucin
Simple columnar epithelium location
Lining of most digestive tract
Simple columnar ciliated epithelium structure
Same as non-ciliated columnar epithelium except that cells have cilia on their apical surface
Simple columnar ciliated epithelium function
Secretion of mucin, movement of mucus along apical surface by action of cilia, movement of oocyte through urine tube
Simple columnar ciliated epithelium location
Larger bronchioles of respiratory tract, lining of uterine tube
Structure of Stratified squamous epithelium-nonkeratinized
-multiple layers of cells, named for appearance of apical cells that are squamous
Function of stratified squamous epithelium-nonkeratinized
Protection against abrasion
Location of stratified squamous epithelium-nonkeratinized
Lining of oral cavity, esophagus, vagina, anus
Structure of stratified squamous epithelium-keratinized
Multiple layers of cells
More superficial cells are dead
Lack nuclei
Filled with protein keratin
Function of stratified squamous epithelium-keratinized
Protection against abrasion
Location of stratified squamous epithelium-keratinized
Epidermis of skin
Stratified cuboidal epithelium description
Two or three layers of box-shaped cells
Stratified cuboidal epithelium functions
Protection and secretion
Stratified cuboidal epithelium location
Sweat glands
Stratified columnar epithelium description
Two or three layers of tall, elongated cells
Stratified columnar epithelium functions
Protection and secretion
Stratified columnar epithelium locations
Salivary glands,some regions of male urethra
Pseudo stratified columnar epithelium structure
Single layer of columnar epithelial cells of different heights, all connect to basement membrane but not all reach apical surface, this And layered appearance if nuclei suggest multiple layers of cells.
Ciliated with globlet
Pseudostartified columnar epithelium function
Protection, secrete mucin, movement of mucus
Pseudostartified columnar epithelium location
Lines most of respiratory tract
Transitional epithelium structure
Multiple layers of cells of varying shapes
Cells are cuboidal when the organ is relaxed but squamous when the organ is stretched
Transitional epithelium functions
Allow dissension of organs that fill with urine
Transitional epithelium locations
Ureters, urinary bladder, and part of male urethra
Connective tissue
Most diverse, abundant, widely distributed, and structurally varied of all four tissue types
Functions is to connect one structure to another structure
Is the glue and filler of the body
Ex: tendons, ligaments, body fat, bones, and cartilage
Structural component of connective tissue
-Cells: different cells for different types of ct- bone cells, cartilage cells, fat cells
-Protein fibers: elastic fibers, collagen, reticular fiber
-Ground substance: a mixture of proteins and carbohydrates with variable amounts of salts and water.
The protein fibers and ground substance comprise the Extracellular matrix, which is produced by the CT cells
Functions of connective tissue
- physical protection
- support and structural framework
- binding structures
- storage
- transport
- immune protection
Classification of connective tissue
CT proper
Supporting CT
Fluid CT
-blood
3 types of protein fibers produced by CT cells and secreted into the Extracellular matrix
- collagen fibers
- elastic fibers
- reticular fibre
Collagen fibers
- Long, unbranching, strong, flexible, and resistant to stretching.
- they make up 25% of all protein in the human body, making collagen the most abundant protein.
Elastic fibers
Thinner than collagen, stretch easily, branch, and rejoin.
These fibers allow structured such as blood vessels to stretch and relax
Reticular fibers
- Thinner than collagen fibers, form a meshwork-like configuration
- they are found in organs with abundant spaces such as liver, lymph nodes, and spleen-act as packing material.
Ground substance of connective tissue proper
- A combination of proteins and carbohydrates
- additional content such as water and salts can result in a texture anywhere from semifluid(adipose,fat) to hard (bone)
Areolar CT structure
Fibroblasts, collagen, and elastic fibers, viscous ground substance
Areolar CT function
Packing around organs-attaches to adjacent structures
Areolar CT location
Major component of subcutaneous layer of skin
Surrounds individual nerve and muscle cells
7 forms the outer layer of blood vessels
Adipose CT
Known as fat
Adipose CT structure
Composed mainly of adipocyte(fat cells) that are filled with one droplet of lipid
Adipose CT functions
Cushioning of organs, thermal insulation, energy storage
Adipose CT locations
Subcutaneous layer of skin, surround kidney
Reticular CT structure
Contains reticular fibers, fibroblasts, and leukocyte
Reticular CT function
Part of lymphatic organs
Reticular CT location
Found in spleen, lymph nodes and bone marrow
Dense regular CT structure
Fibers(mostly collagen) packed tightly together and aligned parallel to applied force
Dense regular CT function
Provides great strength and flexibility, primarily in a single direction
Dense regular CT locations
Found in tendons(attach muscle to bone) and ligaments(attach bone to bone)
Dense irregular CT structure
Bundle of collagen fibers extending in all directions
Dense irregular CT function
Provide tensile strength in all directions
Dense irregular CT locations
Found in reticular layer of the dermis, capsule around the organs such as the liver, kidney, and spleen, outer covering of muscle and nerves
Elastic CT structure
Elastic and collagen fibers are arranged irregularly
Elastic CT function.
Predominance of elastic fibers provides ability to stretch and recoil
Elastic CT location
In the vocal cords and middle layer of large and medium sized arteries
Cartilage
-Cells are called chondrocytes
-Extracellular matrix is a gel like and contain collagen and elastic fibers
-the only avascular connective tissue
-provides support along with flexibility
-chondrocytes occupy small spaces enclosed by their Extracellular matrix and lacunae
Three types: 1.hyaline 2.elastic 3. Fibrocartilage
Hyaline cartilage structure
Glassy appearing matrix, chondrocytes irregularly scattered throughout
Hyaline cartilage function
Smooth surface for movement, supports soft tissue
Hyaline cartilage location
Found in fetal skeleton, and ends of bones that articulate with each other, in trachea, larynx, and nose
Elastic cartilage structure
- Abundant elastic fibers form web-like mesh around lacunae.
- chondrocytes almost indistinguishable from those of hyaline cartilage, closely packed with little Extracellular matrix.
Elastic cartilage function
Maintains structure and shape while permitting extensive flexibility
Elastic cartilage location
External ear, epiglottis of larynx
Fibrocartilage structure
Readily visible, parallel bundles of large collagen fibers; chondrocytes often arranged in parallel rows; densely interwoven collagen fibers contribute to the durability
Fibrocartilage function
Strong support and shock absorption in areas of heavy pressure and compression
Fibrocartilage location
Intervertebral discs, pubic synthesis and knee joints(menisci)
Bone
- Cells are called osteocytes reside in lacunae
- calcified Extracellular matrix is a unique mixture of collagen and bone salts.
- this mixture provides extreme strength(from the bone salts)and microflexibility(from the collagen)
- 2types: compact+spongy bone
Compact bone structure
Matrix arranged in osteon(concentric lamellae around a central canal); laconae located at boundaries of lamellae, canalaculi connect lacunae with central canal.
Compact bone function
Supports, protects, levers for muscles, stores calcium
Compact bone location
Bones of the body
Spongy bone structure
Same matrix material as compact bone and may have lamellae but lack central canal
Spongy bone function
Same as compact bone but also is cite of hemopoiesis (formation of blood cells)
Spongy bone location
Central layer of flat bone, inner surface of some long bones
Fluid connective tissue is composed of:
Plasma, erythrocytes, leukocytes,platelets
Plasma
A watery ground substance containing protein fibers
Erythrocytes
Red blood cell
Leukocyte
White blood cells
Platelet
Fragments of blood cells involved in blood clotting
Muscle tissue
- Comprised of cells called fibers
- when stimulated by the nervous system,fibers shorten or contract
- the result of contraction is movement(movement of bones, blood, food,sperm)
3types: skeletal,cardiac,smooth
