The four types of tissues are..
- 1. Epithelial tissue
- 2. Connective tissue
- 3. Muscle tissue
- 4. Nervous tissue
- • All cells in your body belong to one of thefour types of tissues
Functions of Epithelial Tissue
- 1. Physical protection – from dehydration, abrasion and physical, chemical and biologicalagents
- 2. Selective permeability– regulates the passage of certain molecules in or out of acertain region of the body
- 3. Secretion -- some epithelial cells called exocrine cells produce secretions such as sweat or oil
- 4. Sensations – possess nerve endings that can detect light, taste, sound, smell and hearing
- • Glands perform a secretory function
- • They produce mucin, hormones, enzymes and waste products
- • *Glands can be either exocrine or endocrine.
CONNECTIVE TISSUE (CT)
- • Function is to “connect” one structure to another structure
- • CT is the “glue” and “filler” of the body
Functions of Connective Tissue
- 1. Physical protection
- 2. Support & structural framework
- 3. Binding of structures
- 4. Storage
- 5. Transport
- 6. Immune protection
Development of Connective Tissue
- • Arises from mesoderm
- • Two types of embryonic CT:
- 1. Mesenchyme – source of all adult CT
- 2. Mucous – found in umbilical cord and can contain stem cells for future use by the individual
Cells of Connective Tissue Proper
- 1. Resident cells include fibroblasts, adipocytes, fixed macrophages and mesenchymal cells
- 2. Wandering cells include mast and plasma cells, free macrophages and leukocytes
Fibers of Connective Tissue Proper
-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?
-thinner than collagen,stretch easily, branch and rejoin. These fibers allow structures such as blood vessels to stretch and relax
- thinner than collagen fibers, form a meshwork-like configuration, found in organs with abundant spaces such as liver, lymphnodes and spleen…..packing material
- 1. Collagen fibers
- 2. Elastic fibers
- 3. Reticular fibers
Connective Tissue Proper
Can be classified into two categories..relate them to protien fibers and ground substance
- 1. Loose CT – has fewer protein fibers and more ground substance
- 2. Dense CT – has more protein fibers and less ground substance
Loose Connective Tissue
-known as “fat”, comprised mainly of adipocytes (fat cells) and very little else
-reticular fibers, fibroblasts and leukocytes, found in spleen, lymphnodes and bone marrow
Supporting Connective Tissue
The two types of supporting connective tissue are:
Cells are called what? What do they have and what does it contain? What is their function?
- • Cells are called chondrocytes. They secrete a gel-like extracellular matrix containing collagen and elastic fibers
- • Chondrocytes occupy small spaces enclosed by their extracellular matrixcalled lacunae
- • Provide support and with stand deformation such as the nose and the ear
Where is hyaline cartilage tissue found?
Nose, shoulder, trachea
Where is fibrocartilage tissue found? And what is it's function?
- Found in discs in back
- Strength in between bones with stress
Elastic Cartilage is found where?
Cells are called what? What is the extracellular matrix made up of? What's its function?
- • Cells are called osteocytes
- • collagen and bone salts
- • This mixture provides extreme strength(from the bone salts) and micro-flexibility (from the collagen)
Fluid Connective Tissue
Comprised of the following components(4)..
Where is it found?
- 1. Erythrocytes – red blood cells
- 2. Leukocytes – white blood cells
- 3. Platelets – fragments of blood cells involved in blood clotting
- 4. Plasma -- a watery ground substance containing protein fibers
- 5. Blood
What are the cells called? What happens when it is stimulated by the nervouse system? What is the result?
- • Comprised of cells called fibers
- • fibers shorten or contract
- • movement i.e.movement of bones, blood, food, sperm
Classification of Muscle Tissue
Three types of muscle:
- 1. Skeletal
- 2. Cardiac
- 3. Smooth
Skeletal muscle cannot do what?
Where is its function?
Pulls in multiple directions
Where is this located?
Organs and vessels
Two types of cells? Definition? Function of nerve cells?
- 1. Neurons -- nerve cells that are capable of initiating and conducting electrical activity throughout the body
- 2. Neuroglia – cells that support the neurons
- 3. communication and control of body functions
What does a dendrite do and where is it located?
What does an axon do and where is it located?
- Dendrite is farther down the neuron and it collects info
- An axon is right at the stem of a neuron and it sends out signals
Tissue Change and Death
Tissues can undergo change in form, size or number during the aging process(5):
- 1. Metaplasia – epithelia lining the respiratory airways ofpeople who smoke change from pseudostratifiedciliated to stratified squamous epithelium
- 2. Hypertrophy – increase in the size of existing cells
- 3. Hyperplasia – increase in the number of cells in atissue
- 4. Neoplasia – out of control growth which forms a tumor
- 5. Atrophy – shrinkage of tissue either by cell size or cellnumber