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Chapter 5
Tissues
Tissues
• TISSUES: Organization or communities of similar cells often embedded in nonliving intracellular material called matrix.
• Histology - The study of tissues
Types of Tissue
• Epithelial• Connective• Muscle• Nervous
Appear within 2 months of fetal development.
Epithelial Tissue
• Epithelial - lack blood vessels (avascular), therefore they receive oxygen through diffusion.
• Function:– Protection - skin, mouth, stomach, etc.– Sensory - skin, nose, ears– Secretion - hormones, mucus, digestive
juices– Absorption - respiration, gut– Excretion - urine from kidneys
Structure of Epithelial Tissue
• Cells are tightly packed, little intracellular material.
• Always contains one free surface and one surface attached to a basement membrane = connective tissue.
• Membranous - thin tissue layer– Squamous - flat, platelike: blood vessels, alveoli– Columnar - narrow, cylindrical: uterine lining– Cuboidal - cubed shaped: glands– Simple - one layer of cells– Stratified - multiple layers of cells– Pseudostratified columnar - single layer of
cylinders of different heights
Simple Squamous
• Squamous – flat, platelike: blood vessels, alveoli
Simple Columnar
• Columnar – narrow, cylindrical: uterine lining
Simple Cuboidal
• Cuboidal – cubed shaped: glands
Stratified Squamous
• Stratified – multiple layers of cells
Pseudostratified Columnar
• Pseudostratified Columnar – single layer of cylinders at different heights
Structure of Epithelial Tissue Continued
•Glandular - specialized for secretion - function singularly or in clusters - exocrine – discharges secretions
into ducts that open onto surfaces like the skin and digestive tract (ex. tearducts)
- endocrine – discharges secretions into blood or tissue fluid. ex. Thyroid, pituitary
Classified according to the way they secrete their products. Types of exocrine glands: a. Merocrine – releases fluid by exocytosis
i. Serous cells in the linings ofthe body cavity
ii. Mucus cells in the liningsof the digestive and respiratorysystems.
Ex. Salivary glands, sweat glands,Pancreatic glands.
b. Apocrine – Lose small portions of their glandular cell bodies. Ex. Mammary glands.
c.Holocrine – entire cell released with fluidEx. Sebaceous glands in skin
Transitional Epithelium:
Note scalloped edges ofcells on free surface!
Specialized to changein response to increased tension. (Expandable)
•Found in inner lining of urinary bladderand lines the uretersand part of the urethra.
Transitional epithelium changes its appearance with stretching. The epithelium on the left is relaxed and the cells appear stacked.
On the right, the epithelium is stretched,the epithelial cells flatten and the overall epithelium becomes thinner.
http://www.nku.edu/~dempseyd/URINARY_1.htm
A. Simple
1. Simple squamous
2. Simple cuboidal
Basement membrane
3. a. Simple columnarb. Microvillic. Cilia - Ciliated columnar
4a. Glandular
4 b, c, Pseudostratified
B. Stratified5 a. Stratified squamous
6. Stratified cubodial
7a and b: Transitional
Connective Tissue
• Function• Attachment
– muscle to muscle– muscle to bone
• Support - organs and body as a whole.– produce blood cells – store fat– serve as framework
• Defense mechanism - fight against infection and repair tissue damage.
Connective Tissue
• Structure– Cells far apart– Have matrix (intercellular material-fluids,
fibers, etc…) between cells.
• Types– Adipose– Cartilage– Bone– Blood
Types of Connective Tissue
• Adipose – fat cells– Protective covering around organs– Insulation– Distribution is different in males and females– Stores energy
Types of Connective Tissue Continued
• Cartilage – dense fibrous– shock absorbers– heals very slowly (no direct blood
supply)– Types
a. Hyaline – most common, found on the ends of bone.
b. Elastic – more elastic, found on earsc. Fibrocartilage – tough tissue, pads
between disks in vertebrae.
Types of Connective Tissue Continued
Hyaline
Fibrocartilage
Elastic
Types of Connective Tissue Continued
• Bone– Specialized to form
blood– Allows attachment
for muscle
Types of Connective Tissue Continued
• Blood – liquid state– Oxygen movement– Red (transports
gases), white (fight infection), and platelet cells (blood clotting)
– Plasma = fluid portion– Defense against
bacteria– Ischemia = decrease
oxygen supply to organs
Muscle Tissue
• Function– Movement through contraction
• Types– Skeletal – Smooth– Cardiac
Muscle Tissue Continued
• Skeletal– Striated and voluntary– Muscles attached to bone– Controllable
Muscle Tissue Continued
• Smooth– Involuntary– Found in the walls of hollow internal organs
Muscle Tissue Continued
• Cardiac– Striated and involuntary– Only found in the heart
Nervous
• Function– Regulate and integrate communication
• Types– Neurons– Neuroglia
Nervous Continued
• Neurons – send and receive messages• Neuroglia – connect and support neurons
Nervous Continued• Structure
– Soma – body of neuron– Axon – carries impulses away from neuron– Dendrite – carries impulses to neuron