Chapter 3 - Histology Flashcards
Tissue
Collection of similar cells grouped together to function as a unit
Four types of tissues: epithelial, muscular, connective, and nervous
Characteristics of epithelial tissue
Covers the body surface, covers, lines internal organs, and forms glands
Functions in protection, absorption, and secretion
Cells are tightly packed together, forming layers and sheets, means that epithelial tissue has a free or exposed surface called apical surface; opposite surface that sits on a basement membrane, is called the basal surface
Epithelial tissue is avascular (no direct blood supply)
Most types of epithelial tissue are named based on two characteristics: number of layers and shape of individual cells
What are the two characteristic that gives certain types of epithelial tissue their names
Number of layers and shape of cells
Simple
Single layer
Stratified
Multiple layers
Squamous
Flat
Cuboidal
Tall as it is wide (cube)
Columnar
Taller than it is wide (column)
Apical surface
Free, exposed edge (top)
Lateral surface
Contacts adjacent epithelial cells (under apical surface)
Basal surface
Contacts basement membrane (under lateral surface)
Basement membrane
Connects epithelial tissue to underlying tissue (bottom)
Simple squamous epithelium
Single layer of flat cells
Forms very thin and delicate membranes
Allows for easy movement of molecules across the membrane via processes such as osmosis and diffusion
Found in the kidney glomeruli, alveoli of the lungs, lining of the heart, blood vessels, lymphatic vessels, and serous membranes
Simple cuboidal epithelium
Single layer of cube-shaped cells
Capable of secretion and absorption
Found in kidney tubules, small ducts and glands, covering the ovaries
Simple columnar epithelium
Single layer of column-shaped cells
Capable of absorption and secretion
Found lining most of the digestive tract, gallbladder, ducts of large glands, small bronchi, and uterine tubes
Secretions if the digestive tract lining possess microvilli
Bronchi and uterine tube lining is cilliated
Microvilli
Called a brush border
Short slender cell processes that increase the surface area available for absorption of nutrients
Cilia
Hair-like
Beat in unison to propel substances: mucus in the bronchi and ova in the uterine tubes
Stratified squamous epithelium (keratinized)
Many layers of flat cells
Deepest layers are almost cuboidal in shape and actively dividing
Cells become flatter as they are pushed toward the surface by newer cells
Supper layers are dead and filled with keratin
Found in the epidermis of the skin
Keratin
Hard protein
Designed for protection
Stratified squamous epithelium (nonkeratinized)
Same characteristics as keratinized stratified squamous epithelium, except upper layers of cells do not die and do nit become filled with keratin (contain visible nuclei)
Protects the underlying tissues
Found in the lining of the esophagus, vagina, and mouth
Pseudostratified columnar epithelium
Cells are in only one layer but are of different heights, which makes the tissue appear to be stratified
Very tightly packed together, so that the nucleus appear at various levels
When found lining the trachea and most of the upper respiration tract it contains goblet cells that secrete mucus and possess cilia that beat to sweep the mucus up and out of airways
Also found lining the male reproductive ducts (ciliated and non-ciliated) and ducts of large glands (non-ciliated)
Transitional epithelium
A stratified tissue
Apical layers of cells are larger and rounder; cells slide past each other to allow stretching of the tissue layer; stretching occurs as the bladder fills and the cells change from rounded shape to a flattened shape
Found lining the urinary bladder, ureters, and urethra, allows distension of these organs
Characteristics of connective tissue
Function to bind, support, protect, and fill spaces
Fewer cells compared to other tissue types and are widely spread apart
Space between the cells is occupied by a matrix
Matrix is non-cellular, non-living, and consists of fibers and ground substances
Has a rich blood supply exceptions of cartilage (avascular) and tendons and ligaments (poorly vascularized)
Most abundant toe of tissue in the body, varies directly on appearance, structure, and function
Two major classifications for connective tissue: connective tissue proper and specialized connective tissue
What are examples of connective tissue proper
Areolad
Dense irregular
Dense regular
Reticular
Adipose
Elastic
What are examples of specialized connective tissue
Hyaline cartilage
Fribrocartiakge
Elastic cartilage
Compact bone
Cancellous bone
Blood
What are some fiber types
Collagen, elastic, and reticular
Matrix
Substance produced and secreted by connective tissue cells
Compositor of matrix differs with each type of connective tissue and is specialized for the function of the tissue
Areolar (loose) connective tissue
Gel-like matrix with collagen and elastic fibers
Cells include fibroblasts, mast cells, and microphages
Forms a layer to which epithelial cells may bind, as in the papillary layer of the dermis
Found Ariana capillary networks where it binds and protects the capillaries
Dense irregular connective tissue
Matrix consists of bundles of collagen fibers and little ground substance
Random arrangement of collagen bundles gives this tissue structural strength to resist tearing in all directions
Main cell toe if a fibroblast
Found in the reticular layer of the dermis, wall of digestive tract, and fibrous capsules of organs and joints
Dense regular connective tissue
Matrix contains parallel bundles of collagen fibers and little ground substance
Parallel arrange,ent of collagen bundles gives this tissue great tensile strength in one direction
Main cell type is a fibroblast
Forms ligaments and tendons, where it’s tensile strength is able to anchor bones to each other and muscles to bone
Reticular connective tissue
Matrix consists of reticular fibers arranged in a network and loose ground substance
Main cell types is reticular cells
Forms flexible internal scaffolding that supports other toes of cells
Found in lymph nodes, spleen, and bone marrow
Adipose tissue
Composed primarily of cells called adipocytes that store lipids
Sparse matrix and few fibers
Functions as protective padding, thermal insulation, and energy storage
Found in subcutaneous layer of the skin, around the kidneys, eyeballs, heart, in the breasts, and in the abdominal cavity
Elastic connective tissue
Modified dense regular connective tissue containing a high proportion of elastic fibers
Allows recoil of tissue following stretching
Found in the walls of large arteries and the walls of the bronchial tubes
Hyaline cartilage
Very firm matrix containing collagen fibers; however, these fibers will not be visible in microscope slides
Functions to reduce friction between bones
Cells are chondrocytes located in cavities called lacunae
An avascular tissue
Found covering the ends of long bones within joints, costal cartilage, and cartilage of nose, trachea, and larynx
Fibrocartilage
Matrix contains collagen fibers like hyaline cartilage, but arrangement of fibers is more regular and readily visible in the matrix
Tissue is a shock absorber with high tensile strength
Cells are chondrocytes in lacunae
Found in the intervertebral discs, outbid symphysis, and mensci of the knee
Elastic cartilage
This firm matrix has a greater number of elastic fibers than found in other types of cartilage
Cells are chondrocytes in lacunae
Very flexible cartilage
Found in auricle of outer ear and epiglottis
Compact bone
Collagen fiber matrix that has been calcified to form hard tissue
Cells are osteocytes which are found in small cavities of lacunae (singular is lacuna), lacunae are interconnected by network of very small canals called canaliculi (singular is canaliculus)
Compact bone contains closely packed Ostend or Haversian systems
An osteopath consists of a central canal (Haversian canal), surrounded by concentric rings of matrices caked lamellae (singular is lamella)
Found in bones of the skeleton
Cancellous (spongy) bone
Is lighter and less dense than compact bone
Consists of plates of bonemeal called trabeculae, that form small, irregular cavities that contain red bone marrow
Found deep to compact bone
Red bone marrow produces blood cells in process called hematopoiesis
Blood
Watery matrix called plasma and no fibers
Blood cells are suspended in the plasma
Transport respiratory gasses, nutrients, wastes, and other substances either in the cells or dissolved in the plasma
Protect the body against disease and maintain hemostasis (stops bleeding when a vessel is damaged)
Found in blood vessels
Muscular tissue
Three types of muscular tissue: skeletal, smooth, and cardiac
Individual cells in this type of tissue is called muscle fibers
Contractile proteins: actin and myosin inside muscle fibers arranged to slide past each other causing contractions
In skeletal and cardiac muscle, the proteins are organized into visible patterns called striations
Skeletal muscle
Attaches to bones and produce movement
Voluntary (consciously move)
Muskie fibers long, slender, multinucleated, and lie parallel
Contractile proteins are highly organized and visible in striations
Smooth muscle
Located in the walks of hollow organs such as the stomach, urinary bladder and muscular blood vessels
Also called visceral muscle
Spindle shaped
Have a single nucleus and are involuntary
No visible striations but have actin and myosin
Cardiac muscle
Only in the heart wall
Responsible for generating the force capable of pumping blood through the blood vessels
Fibers are branched and have a singular nucleus, are striated, and involuntary
Intercalated discs found connecting adjacent cells which allows rapid communication between adjacent cells that is necessary for the fibers to contact as a unit
Nervous tissue
Consists of 2 different types of cells: neuron and neurogilal cells
Conducts impulses to carry information from one area of the body to another
Neuron
Cell capable of generating and conduction an electrical impulse
Consists of a cell body, one or more dendrites (receiving incoming impulses), and a single axon to conduct impulse to the next cell
Neuroglial cells
An assortment of cells that protect, support, and insulate neurons, but do not carry impulses
