Mod2-Obj5: Four types of tissues in the body and their function Flashcards
Cellular differentiation
All body cells contain the same genes (DNA)
-Arise from the same fertilised cell
How do we get different types of cells?
- Different genes turned ‘on’ and ‘off’
- Specialise early in gestation
- Change from generalised ‘all purpose’ state (stem cell) into one with a specific function
- Tailored protein synthesis differentiates cell
Formation of tissues
A collection of cells similar in structure that perform a common or related function to form 4 primary tissue types
- ) Epithelial tissue
- ) Connective tissue
- ) Nervous tissue
- ) Muscle tissue
- All of the body’s organs consist of a combination of the 4 different tissue types
Location of nervous tissue
Internal communication
Location of muscle tissue
Produces movement; expand or contract
Location of epithelial tissue
Cover; secretion and absorption
Location of connective tissue
Support, protects, tranport
Epithelial tissue
Sheets of cells that:
1.) Form boundaries between different environments i.e.) skin
2.) Covering and lining epithelia
External and internal surfaces i.e.) respiratory passage
3.) Glandular epithelia
Secretory tissue glands i.e.) release of hormones
Functions of epithelial tissue
Protection=Skin Absorption=Digestive tract Filtration=Kidney Excretion=Kidney Secretion=Gut and respiratory Transport of mucous=Respiratory Sensory function=Tongue and nose
Structure of epithelial tissue
Cells are closely packed together
-Little spaces to form continuous tissue
-Attached to basement membrane
Lacks blood vessels (avascular)
-Nutrients from underlying connective tissue via diffusion
Regenerate quickly
Can have microvilli and cilia (help protect organs by filtering particles that enter the body)
Classification of epithelial tissue
Named by number of layers and cell shape Layers: 1.) Single-simple 2.) Multiple-Stratified Shape: 1.) Squamous 2.) Cuboidal 3.) Columnar
Connective tissue
Most abundant of the 4 tissue types
-Highly vascular
Functions of connective tissue
- Structural framework for the body
- Transport fluids and dissolved materials
- Protects organs
- Supports, surrounds and interconnect other tissues
- Store energy
- Defend the body
4 classes of connective tissue
- ) Connective tissue proper (dense and loose)
- ) Cartilage
- ) Bone
- ) Blood
Structure of connective tissue
All connective tissue contains
- Few widely separated specialised cells
- Ground substance
- Collagen and elastin fibres
Structure of connective tissue: Extracellular matrix (non-living)
- All materials other than cells
- Collagen and elastin
- Makes up the bulk of connective tissue
Structure of connective tissue: Extracellular protein fibres
1.) Collagen
Tough fibres with high tensile strength
2.) Elastic
Long thin fibres, that act like rubber bonds
3.) Reticular
Short fibres continuous with collagen fibres
Specialised cells of connective tissue
CT classes have immature and mature resident cells 1.) Immature cells (blast) Secrete ground substances and fibres 2.) Mature cells (cyte) Maintains matrix 3.) Other cells Blood (WBC, RBC, macrophages) Adipocytes (fat)
Connective tissue proper
6 subclasses of loose and dense CT
-Contains fibroblasts and fibrocytes
Connective tissue proper: Loose CT
Loose arrangement of fibres
-Large amounts of ground substance
(support blood vessels, soft tissued organs)
Connective tissue proper: Dense CT
Closely packed fibres
-Little ground substance, poorly vascularised
(doesn’t have a lot of blood, acts as an anchor)
Connective tissue proper: Adipose
A class of CT proper and contains adipocytes and fibrocytes
Cartilage
Qualifies between dense connective tissue and bone
- Consists of collagen and some elastic fibres
- Up to 80% water
Cartilage: Chondroblasts produce new matrix…
If cartilage is disrupted
Cartilage: Support and absorb compression…
Prevents abrasion occurring in the bone
Cartilage: Lacks nerve fibres and is avascular…
Nutrients enters cartilage through compression
Bone
Abundant collagen fibres
Bone: Osteoblasts
- Produce organic matrix
- Matrix very firm (inorganic calcium salts)
- Osteocytes reabsorb bone as needed
Bone is…
Highly vascular, nerve fibres
Functions of bone
- Support and protect
- Store fat
- Synthesise blood cells
Blood
Fluid within blood vessels
Blood mod1
- Consists of blood cells surrounded by plasma
- Blood cells include RBC,WBC
- Contains soluble protein molecules that form fibres during blood clotting
Muscle tissue
Highly vascularised
Three types of muscle tissue
1.) Skeletal Voluntary movement 2.) Smooth Involuntary movement (expand and contract blood vessels-vasodilation and vasoconstriction) 3.) Cardiac In heart
Muscle tissue is composed…
Of muscle cells that contain contractile proteins
Nervous tissue
Main component of the nervous system
- Brain
- Spinal cord
- Nerves
Nervous tissue is composed…
Of neurons and supporting cells
Nervous tissue transmit…
Electrical signals to regulate and control body functions
