Exercise 5: Histology and Body Membranes Flashcards
Tissue
A collection of similar cells grouped together to function as unit.
Four types of tissue.
- ) Epithelial Tissue
- ) Connective Tissue
- ) Muscular Tissue
- ) Nervous Tissue
Apical Surface
The free or exposed surface of tissue.
Basal Surface
Sits on the basement membrane. It is opposite the apical surface of the tissue.
Epithelial tissue is characterized on two things:
- ) Number of layers.
2. ) Shape of individual cells.
Avascular
Epithelial tissues are avascular. It does not have its own direct blood supply.
Simple Squamous ET
Function: Allows for easy movement of molecules across the membrane via processes such as osmosis and diffusion.
Location: Kidney glomeruli, alveoli of the lungs, lining of the heart, blood vessels, lymphatic vessels, and serous membranes.
Simple Cuboidal ET
Function: Secretion and absorption.
Location: Kidney tubules, small ducts and glands, thyroid gland, and covering the ovary.
Simple Columnar ET
Function: Absorption, secretion and protection.
Location: Lining the stomach, intestines, gallbladder, ducts of large glands, small bronchi, and uterine tubes.
**Digestive tract lining possesses microvilli (brush border). They are short slender cell processes that increase the surface area available for the absorption of nutrients.
**Bronchi and uterine tube lining are ciliated. Used to propel mucus in the bronchi and ova in the uterine tubes.
Stratified Squamous ET, Keratinized
Function: Upper layers are filled with keratin, a hard protein. Designed for protection against pathogens, abrasion and chemicals.
Location: Epidermis of skin.
Stratified Squamous ET, Non-Keratinized
Function: Protection against underlying tissue. Upper layers of cell do not die and become filled with Keratin.
Location: Esophagus. vagina, mouth, rectum and anus.
Stratified Cuboidal ET
Function: Absorption, Secretion and Protection.
Location: Ducts of sweat glands.
Stratified Columnar ET (Rare)
Function: Protection and secretion
Location: Protection in the urethra, anus, epiglottis, and pharynx.
Secretion in large ducts of mammary and salivary glands.
Pseudostratified Columar ET
Function: Goblet cells secrete mucus and cilia sweep it out of the airways.
Location: Lining the trachea and male reproductive ducts (ciliated and non-ciliated), and ducts of large glands (non-ciliated).
Transitional ET
Have larger and rounder apical surface cells.
Function: Distension of organs.
Location: Urinary bladder and uterus.
Skeletal Muscle
Voluntary
Function: Allows movement of the skeleton.
Location: Attached to bones.
Smooth Muscle (aka visceral muscle)
Involuntary
Function: Moves substances through digestive, urinary, and reproductive tracts, regulates blood vessel diameter and controls the diameter of respiratory passageways.
Location: Hollow organs such as, stomach, urinary bladder, and muscular blood vessels (arteries)
Cardiac Muscle
Function: Contraction of the heart muscle.
Location: Heart wall.
Contains intercalated disks: Allow for communication between adjacent cells.
Nervous Tissue
Function: generates and conducts an electrical impulse. Carry information from one area of the body to another.
Cell axon= Cell process
Cell dentrites= Cell processes.
Connective Tissue Function
Bind, support, protect and fill spaces.
Three types of Connective Tissue
- ) Connective Tissue Proper
- ) Supporting Connective Tissue
- ) Fluid Connective Tissue
Types of Loose Connective Tissue Proper
- ) Areolar CT
- ) Adipose CT
- )Reticular CT
Types of dense CT proper
- ) Dense regular CT
- ) Dense Irregular CT
- ) Elastic
Types of Supporting CT
- ) Hyaline Cartilage
- ) Fibrocartilage
- ) Elastic Cartilage
- ) Compact Bone
- ) Cancellous Bone
Types of Fluid Connective Tissue
- ) Blood
2. ) Lymph
Matrix
The space between cells. Produced and secreted by the connective tissue cells. Non-cellular, non-living and consists of ground substance and fibers
Types of fibers
- ) Collagen
- ) Elastic
- ) Reticular
Mesenchyme
- Also called Embryonic CT
- Loose, unspecialized tissue that develops in the embryo
- Gel-like ground substance
- Gives rise to all types of adult CT
Areolar CT
- Loose CT
- Gel-like matrix with collagen and elastic fibers
- Cells include fibroblasts, mast cells, and macrophages
- Forms a layer to which epithelial cells may bind, as in the papillary layer of the dermis
- Found around capillary networks where it binds and protects the capillaries.
Adipose CT
- Loose CT
- Composed primarily of adipocytes that store lipids.
- Only example of closely packed cells in CT
- Sparse matrix and few fibers
- Functions as protective padding, thermal insulation and energy storage.
- Found in subcutaneous layer of the skin, around the kidneys, eyes, heart, in the breasts, and in the abdominal cavity.
Reticular CT
- Loose CT
- Matrix consists of reticular fibers arranged in a network and loose ground substance
- Main cell type is reticular cells
- Forms flexible internal scaffolding that supports other types of cells
- Found in lymph nodes, spleen, bone marrow, liver and kidney.
Dense Regular CT
- Dense CT
- Matrix contains parallel bundles of collagen fibers and little ground substance
- Parallel arrangement of collagen bundles gives this tissue great tensile strength in one direction
- Main cell type is a fibroblast
- Forms ligaments and tendons, where its tensile strength is able to anchor bones to each other and muscles to bones.
Dense Irregular CT
- 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 type is a fibroblast
- Found in the reticular layer of the dermis, wall of the digestive tract, and fibrous capsules of organs and joints
Elastic CT
- Dense CT
- Contains a high proportion of elastic fibers
- Allows recoil of tissue following stretching
- Found in walls of large arteries and the walls of brachial tubes
Hyaline Cartilage
- Supporting CT
- Very firm matrix containing collagen fibers. Matrix is compressible. Allows tissue to act as a shock absorber and to reduce friction between bony surfaces
- Cells are chondrocytes located in cavities called lacunae.
- Avascular tissue
- Found covering the ends of long bones within joints, costal cartilage, and cartilage of nose, trachea and larynx.
Fibrocartilage
- Supporting CT
- Matrix contains collagen fibers like hyaline cartilage, but arrangement of fibers is more regular.
- Tissue is a shock absorber with high tensile strength
- Cells are chondrocytes in lacunae
- Found in intervertebral disks, pubic symphysis and menisci of the knee.
Elastic Cartilage
*Supporting CT
*Firm matrix that has a greater number of elastic fibers
*Very flexible
*Found in auricle of outer ear and epiglottis
Cells are chondrocytes in lacunae
Compact Bone
- Supporting CT
- Collagen fiber matrix that has been calcified to form hard tissue
- Cells are osteocytes which are found in lacunae. Lacunae are interconnected by canaliculi
- Contains osteons that consist of a central canal, surrounded by a concentric ring of matrix called lamellae
Cancellous Bone
- Supporting CT
- Lighter and lese dense than compact bone
- Consists of plates of bones called trabeculae that form small, irregular cavities that contain red bone marrow
- Deep to compact bone
- Red bone marrow produces blood cells in a process called hematopoiesis.
Blood
- Fluid CT
- Watery matrix called plasma which contains dissolved protein fibers
- Blood cells are suspended in plasma
- Erythrocytes (red blood cells) transport respiratory gases
- Leukocytes (white blood cells) body defense
- Platelets involved in blood clotting.
- Found within blood vessels
Lymph
- Fluid CT
- Formed when interstitial fluid is transported from extracellular spaces of body tissue through lymphatic vessels until it ultimely returned to the veins of the cardiovascular system.
- contains white blood cells predomininently lymphocytes.
