Chapter 4: Tissues Flashcards
Define Tissues and what is the study of tissues?
are composed of groups of similar cells with a common function.
Histology: the study of tissues.
4 Basic Types of Tissues and their role
1) Epithelial Tissue – Covering
2) Connective Tissue – Support
3) Muscle Tissue – Movement
4) Nervous Tissue – Control
Epithelial Tissue
- location
- function
Location
Covers surfaces, lines cavities, & forms glands.
Functions A boundary. Selective barrier. Secretory surface. Protective surface.
Connective Tissue:
- location
- function
Location
Most abundant tissue in the body.
Function:
• Binds and supports -> structural framwoek of our body, gives structural igegrity
• Protection –> bone/cartilage
• Insulation –> adipose tissue, also protects from impact
• Transport of substances blood moves nutrients and O2
• Storage of energy reserves –> adipose tissue stores triglyceride that are broken down and used for NRG
• Source of immune responses –> WBC found in blood and are some first responders
Avasular = no direct blood suppy (ex. Cartilage, relys on structure and tissues nearby that does have a blood suppy)
Poorly vascualrise = some connective tissue
Very vasularised = bone tissue is solid so nothing can diffuse through the thick matrix.
ALL connective tissue has 3 main components:
i) Cells
ii) Ground substance
iii) Fibers
Extracellular matrix = ground substance + fibers.
Old vs. young cells
blasts” are immature cells.
= actively creating the ground /fibers
“cytes” are mature cells.
= evolve from blasts, not dividing, not producing ground/fiber. They are still maintiaing matrix
7 Types of cells
1) Fibroblasts – in all connective tissues that produce/secrete the matrix component
2) Chondroblasts – found in cartilage (condo=cartilage)
3) Osteoblasts – found in bones (osteo = bone)
4) Adipocytes – fat cells that store triglycerides
5) White blood cells – can migrate into other connective tissues from blood to area of injury to deal with infection
6) Mast cells: release heparin (anticoagulant: stops blood from clotting) and histamine (dilates blood vessels: so that immune cells that need to get to the site of injury can get there and start fighting the injection).
7) Macrophages: large phagocytic cells, cells that roam around, develop from WBC and engulf and digest anything that shouldn’t be there
Ground Substance
- Material that fills space between cells and surrounds fibers.
- Consists of water, adhesion proteins and complex polysaccharides.
- Functions: supports cells, binds cells together, stores water, medium for exchange between cells & blood.
Huge variation in the consistency:
-Some ground substance is very liquidly
-Ground substance in cartilage is more gel like
-Bone tissue ground substance is solid
When blood bring nutrients and O2 it must difuse through ground tissue to get to the cell
Fibers - 3
Collagen fibers
- are long, straight fibers composed of collagen protein
- most abundant protein in body
- flexible but strong that allows them to resisit pulling forces
Elastic fibers:
- are thin, branched fibers composed of elastin protein.
- found in skin, lungs, & vessel walls.
- have a stretch/recoil funciton
Reticular fibers:
- are short, thin branched networks of fibers composed of collagen and glycoprotein.
- These are normally found in the spleen,lymp noodes and they make the structure makeup of these organs are mostly reticular fibers due to the highly branched netwroks they can produce
Muscle Tissue
- Define
- types
- Consists of cells (fibers) that contract to produce movement.
- Muscle cell = muscle fiber (same thing)
There are 3 kinds:
a) Skeletal
b) Cardiac
c) Smooth
Skeletal Muscle
- Many nuclei per cell.
- Long, cylindrical cells (look like fibers)
- Under voluntary control (only ones that are under consious control.)
- Attached to bones. (to create movement)
- Peripheral nuclei ( the reason is that theres lots of dif things that take up spce in the cytoplasm so they’re pushed to the side)
- Striations (are perpediculara and due to the overlap of contractile proteins. This can be used as an identifying characteristic under the microscope)
Function
Moves bones in skeleton.
Cardiac Muscle
- One nucleus, in centre of cell.
- Branched, shorter fibres.
- Under involuntary control.
- Striations.
- Found in the walls of the heart only so unconcious ctrl
Function
Contracts heart to propel blood.
Smooth Muscle
- One nucleus, in centre of cell.
- Short, spindle-shaped cells.
- Under involuntary control.
- No striations.
- Found in walls of hollow organs.
- Thicker in the middle then taper off to a point
- Found in hollow organs such as lining the walls of the digestive tract and the cells sqeeze the tract that contracts the diameter and also to shorten it which helps to move food through the tract.
Function
To propel contents of hollow organs.
Nervous Tissue
- define
- types
• Is the main component of the nervous system (brain, spinal cord, & nerves) which regulates and controls body functions.
Contains 2 major cell types:
a) Neurons
b) Neuroglia
Nervous Tissue 2 types
a) Neurons
Are nerve cells that generate and conduct nerve impulses.
b) Neuroglia
- Are the more numerous non-conducting cells which function in support, insulation, and protection of neurons.
- maintain the nerve cells
