Lecture 2 Flashcards
Tissues
A group of closely associated cells that perform related function and are similar in structure
Most organs contain 4 tissue types
Epithelial tissue
Covers body surface or lines body cavity Forms parts of most glands Minimal extracellular material Specialized contacts between cells Avascular but innervated Receives nutrients from underlying connective tissue Quickly regenerates
Connective tissue
Support Connects other tissues together Mostly right under epithelium Most diverse and abundant tissue Few cells, abundant cellular matrix Common embryonic origin is mesenchyme
Muscle tissue
Movement, contractility
Nervous tissue
Control, excitability
Functions of epithelia
Protection Secretion Absorption Diffusion Filtration Sensory reception
Simple epithelia
Single layer of cells attached to basement membrane
Stratified epithelia
Multiple layers of cells
Squamous
Cells are wider than tall: plate like
Cuboidal
Cells are as wide as they are tall
Columnar
Cells are taller than they are wide
Simple squamous epithelium
Diffusion and filtration
Secretes lubricating substances in serosae
Located in renal corpuscles, alveoli of lungs, lining of heart, blood and lymphatic vessels (body cavities)
Simple cuboidal epithelium
Secretion and absorption
Located in kidney tubules, secretory portions of small glands, ovary surface
Stratified squamous epithelium
Adapted for protection from abrasion
Deeper layers of cells appear cuboidal or columnar
Thickest epithelial tissue
Regenerates from below
Named according to shape of cells at apical layer
Stratified cuboidal epithelium
Generally two layers of cube-shaped cells
Protection
Located at ducts of mammary glands, salivary glands and largest sweat glands
Basement membrane and diabetes
Basement membrane can become thick
Due to increase amounts of glucose binding to proteins of BM: glycosylation, especially in eye or kidney
Simple columnar epithelium
May contain goblet cells
Absorption, secretion of mucus, enzymes, etc
Ciliated types propel mucus or reproductive cells by ciliary action
Location of non-ciliated simple columnar epithelium
Lines digestive tract, gallbladder, ducts of some glands
Location of ciliated simple columnar epithelium
Lines small bronchi, uterine tubes and uterus
Pseudostratified columnar epithelium
All cell originate at basement membrane Only tall cells reach apical surface May contain goblet cells and bear cilia Nuclei lie at varying heights within cells, giving impression of stratification Secrete mucus and propel mucus by cilia
Location of non-ciliated pseudostratified columnar epithelium
Ducts of male reproductive tubes
Ducts of large glands
Location of ciliated pseudostratified columnar epithelium
Lines trachea and most of upper respiratory tract
Goblet cell
Unicellular exocrine gland
Shaped as goblet
Protects and lubricates many internal body surfaces
Kartengeer’s syndrome
Immotile cilia syndrome
Inherited disease
Frequent respiratory infections
Infertility
Keratinized simple squamous epithelium
Epidermis
Contains protective protein keratin
Waterproof
Surface cells are dead and full of keratin
Nonkeratinized simple squamous epithelium
Forms moist lining of body openings
Stratified columnar epithelium
Several layers
Basal cells usually cuboidal, superficial cells elongated
Protection and secretion
Rare tissue type, found in male urethra and large ducts of some glands
Transitional epithelium
Resembles both stratified squamous and stratified cuboidal
Basal cells cuboidal or columnar
Surface cells dome or squamous depending on stretch of organ
Stretches readily and permits distension of urinary organ by containing urine
Lines ureters, bladder and part of uterus
Main classes of connective tissue (4)
- Connective tissue proper
- Cartilage
- Bone tissue
- Blood
Important functions of connective tissue types
Forms basis of skeleton
Store/carry nutrients
Surround blood vessels and nerves
Lead fight against infection
Extracellular matrix
Composed of ground substance and fibers
Produced by cells of connective tissue
Structural elements of connective tissue (2)
- Fibers
2. Ground substance
Connective tissue fibers
Support Have unique properties 1. Collagen 2. Reticular 3. Elastic
Collagen fibers
Strongest
Resist tension
Reticular fibers
Bundles of special type of cartilage
Elastic fibers
Contain elastin, recoil after stretching
Connective tissue ground substance
Usually gel-like substance containing proteoglycans and glycoaminoglycans
Cushions and protects body structures
Holds tissues fluid
Blood is an exception (plasma is not produced by blood cells)
Connective tissue proper
Loose connective tissue
Dense connective tissue
Loose connective tissue
Areolar, adipose, reticular
Dense connective tissue
Collagen, elastic
Areolar connective tissue
Main battlefield in fight against infection
Contains macrophages, plasma cells, mast cells, WBC
All 3 types of fibers for support
Fibroblasts produce fibers and ground substance
Location of areolar connective tissue
Widely distributed under epithelia
Forms lamina propria of mucous membranes, packages organs and surrounds capillaries
Adipose connective tissue
Matrix is areolar connective tissue with closely packed adipocytes
Provides reserve food fuel, insulates against heat loss and supports/protects organs
Location of adipose connective tissue
Under skin in the hypodermis, around kidneys and eyeballs, within abdomen and in breasts
Dense regular connective tissue
Collagen fibers are parallel to direction of pull, few elastic fibers
Have more collagen than areolar connective tissue
Fibroblasts are located between collagen fibers
Poorly vascularized
Attaches muscles to bones, bones to bones
Location of dense regular connective tissue
Tendons, most ligaments, aponeuroses
Dense elastic connective tissue
Dense regular connective tissue containing high proportion of elastic fibers
Allows recoil of tissue following stretching, maintains pulsatile flow of blood through arteries, aids passive recoil of lungs following inspiration
Location of dense elastic connective tissue
Walls of large arteries, within certain ligaments associated with the vertebral column, within the walls of bronchial tubes
Blood tissue
Atypical connective tissue
Consists of cells surrounded by nonliving matrix
RBC, WBC
Transport respiratory gases, nutrients, wastes and other substances
Contained with blood vessels
Covering and lining membranes
Consists of epithelial tissue sheet and underlying connective tissue
- Cutaneous membrane
- Mucus membrane
- Serous membrane
Cutaneous membrane
Skin
Covers the body surface
Mucous membranes
Lines body cavities that are open to the exterior
Serous membranes
Simple squamous epithelium called mesothelium lying on areolar connective tissue
Produces serous fluid
Line body cavities that are closed to the exterior
Muscle tissue
Most muscle cells are called muscle fibers
Cells contain myofilaments which contain actin and myosin
Types of muscle tissue (3)
- Skeletal muscle tissue
- Cardiac muscle tissue
- Smooth muscle tissue
Skeletal muscle
Long, cylindrical, multinucleate cells, obvious striations
Voluntary movement, locomotion, manipulation of the environment, facial expressions
Location of skeletal muscle
Attached to bones or occasionally to the skin
Cardiac muscle
Branching, striated, generally uninucleate cells that interdigitate at specialized junctions: intercalating discs
Propels blod into the circulation, involuntary control
Location of cardiac muscle
In the walls of the heart
Smooth muscle
Spindle-shaped cells with central nuclei, no striations, cells arrange closely to form sheets
Propels substances or objects along internal passageways, involuntary controls
Location of smooth muscle
Mostly in the walls of hollow organs
Nervous tissue
Neurons: branching cells, cell processes may be quite long
Nucleus containing cell body
Non-conducting support cells, neuroglia
Transmit electrical signals from sensory receptors and to effectors that control the activity of the effector organs
Location of nervous tissue
Brain, spinal cord, nerves
Regeneration
Replacement of destroyed tissue with same type of tisue
