What is a tissue?
Group of similar cells that work together to perform a specific function
What is the function epithelial tissue?
- Covers and protects underlying tissue from damage/ injury/ germs/ drying out
- forms a continuous sheet of cells covering external and internal surfaces of body
- attached to underlying tissue by basement membrane
- does not contain blood vessels
Location of epithelial tissue?
- Epithelium- outside
- covers the body
- Endothelium - inside
- lines body cavities, passages and ducts
How is epithelial tissue classified?
- number of layers
2. shape of cell
Where is squamous tissue found?
Inner lining of:
- Blood vessels
What is the structure of squamous epithelial tissue?
- Single layer of thin, flat, closely packed cells with a large surface area
- Spherical central nuclei
What are the functions of squamous epithelial tissue?
- Quick and efficient diffusion of substances
2. Protect and support underlying tissue
Where is simple columnar epithelium found?
- Small intestine
- Vas deferens
- Prostate gland
What is the structure of simple columnar epithelium?
- Single layer of column shaped closely packed cells
2. Oval nucleus near base
What are the functions of simple columnar epithelium?
- Absorb nutrients
- Produce secretions
Protect and support underlying cells
How is a goblet cell shaped to suit its functions?
- Cup shaped
- trap dust and germs
- secrete mucus to keep structure moist
Where is violated columnar epithelium found?
- Nasal cavity
- Fallopian tubes
- Vas deferens
What is the structure of ciliated columnar epithelium?
- Columnar epithelium with cilia on free surface
2. Can have goblet cells
What are the functions of ciliated columnar epithelium?
- Filter air
2. Movement of substances
Where is columnar epithelium with microvilli found?
- Small intestine
What are microvilli?
Microscopic hair-like folds
1. Increase surface area for substance/ nutrient absorption
What is the structure of columnar epithelium with microvilli?
- Elongated cells
- Microvilli on free surface
- Free and highly folded
Where are cuboidal/ glandular cells found?
- Line ducts and glands
Structure of cuboidal/ glandular epithelium?
- Lots of Golgi apparatus in glands
2. No intercellular spaces- has round, central nuclei
Function of cuboidal/ glandular epithelium?
- Absorb nutrients (ducts)
2. Produce secretions (glands)
What is the structure of connective tissue?
- Relatively few cells of various cell types
- Various fibers
- A matrix
- Cells are spread apart and spaces between in filled with matrix
What are the functions of connective tissues?
- Binds tissues and organs together to support body
2. Transports substances within the body
What is the function of soft connective tissue?
- Binds epithelium to other tissues & holds organs in place
Location of areolar tissue
- Continuous layer under skin
2. Fills in between muscles/ organs and blood vessels
What is the structure of areolar tissue?
- Most common
- Loose & irregular arranged tissue
- Jelly-like matrix
- WHITE collagen fibers (branched/ inelastic & parallel)
- YELLOW elastic fibers ( small/ elastic & branched)
What is the function of areolar tissue?
- Attaches underlying muscle to bone
Where is adipose tissue found?
- FAT- under skin
What is the structure of adipose tissue?
- Few fibers
- Fat storing cell
- Very thick= blubber
What are the functions of adipose tissue?
- Secretes matrix & anticoagulant
- Defensive role ( engulfs foreign particles)
- Secretes different fibers
Yellow elastic fiber
- Flexible - forms branch network
White collagen fibers
- Non- flexible - keeps everything tight & together
- Store fat - lots of fat cells in areolar tissue= adipose
- All cells embedded in
- white substance
What is fibrous connective tissue?
- Strong network of collagen fibers
Location and structure of a ligament
- Between bones
2. Yellow Elastic Fibres
Function of ligament
- Keeps joints stable
- Able to stretch
- allow bones to move in different directions from joint
Location and structure of tendons
- Connect muscle to bone 2. White Collagen fibres
Function of tendons
- Grows in bone & strengthens it
2. Inelastic- transmit contraction & relaxation of muscle to bone for movement
What is dense connective tissue?
- Dense tissue with little matrix
- Many inelastic fibres, small number of elastin fibres with a small number of fibroblasts between the fibres
- conjunction with muscle, cartilage and bone in outer TRACHIAL, BRONCHIAL WALLS & BLOOD VESSELS
Function of dense connective tissue?
- Forms fascia, perichondrium & periosteum
- Provides necessary elasticity in trachea, bronchi, vocal chords & blood vessel walls -> only yellow elastic fibres in these structures
- joins bone to bone as ligament
- joins muscle to bone as tendons
Structure of cartilage tissue
- Contains chondrocytes
- secrete rubbery matrix made from chondrin ( protein)
- occur in small fluid filled spaces called lacunae
- Matrix also contain white collagen fibres and yellow elastic fibres
- no nerves/ blood vessels in matrix
What is the perichondrium?
- Fibrous capsule that surrounds cartilage
2. Well supplied by blood vessels but has no nerves
Structure of hyaline cartilage
- Extremely low number of collagen fibres
- No elastic fibres
- Firm, jelly- like matrix
- Clear, glass- like appearance
Location of hyaline cartilage
- End of long bones/ bones in movable joints
- Attaches ribs to sternum
- Forms ‘c’ rings in trachea
- Larynx and bronchi
Function of hyaline cartilage
- Reduces friction in joints
- Attaches bone to bone so movement is possible
- Keeps tubes open
- Forms permanent structures
- Longitudinal growth in long bones
Structure of white fibrous cartilage
- Many collagen fibres arranged in bundles
2. Does not have perichondrion
Location of white fibrous cartilage
- Intervertebral disc
- Pubic symphysis
- Sockets of ball and socket joints
Functions of white fibrous cartilage
- Shock absorber between vertebra
- Protects tendons
Structure of yellow elastic cartilage
- Contains collagen fibres
- Network of branched elastic fibres
- Not as glossy- fibres embedded in matrix
Location of yellow elastic cartilage
- Tip of nose
- Pin a of ear
- Eustachian tubes
Function of yellow elastic cartilage
- Maintains shape & flexibility
2. Gives support to structure
- Central canals
- Run through bones longitudinally
- Contain blood vessels, nerves and lymph vessels
Matrix of bone tissues
- Occur in concentric circles- LAMELLAE- around Haversian canals
- Contain collagen fibres -> bone not brittle
- contains inorganic substances: Ca, P, Mg = hard matrix
Lacunae between lamellae
- Each lacuna contains an osteocyte
What is a canalculi?
- A fine canal that links lacuna to Haversian canal
- allows movement of useful substances (nutrients, O2) and cellular waste to & from blood of Haversian canal to & from all parts of bone tissue
What is blood?
- Liquid connective tissue formed by blood floating in plasma
What is the composition of blood?
- 55% plasma
2. 45% cells
What is plasma composed of?
- Pale straw colour
- 90% water
- Contains inorganic ions (Na, K, Cl)
- Organic compounds ( glucose, amino acids)
- Cellular wage- urea & uric acid
- Dissolved gases - CO2 & O2
- Plasma proteins - fibrinogen & albumen
- Hormones and enzymes
What cells are found in blood?
What is the structure of erythrocytes?
- Red blood corpuscles- carry O2 & CO2
- small, round
- biconcave discs with no nuclei
- hemoglobin- red pigment
- combine with O2 -> oxyhemoglobin
What is significant about the structure of erythrocytes?
- A lot of cells = large surface area for O2 absorption
- Biconcave shape makes surface area for absorption larger
- Flexible - able to be pushed through small blood vessels
What is the structure of leukocytes?
- White blood cells
- large & irregularly shaped with nuclei
What is significant about the structure of leukocytes?
- Move actively through amoeboid movement & engulf foreign particles
- can move out of blood vessels & into intercellular spaces in tissues
- Can produce antibodies -> destroy bacterial toxins
What is the structure of muscle tissue?
- Long & thin
- Parallel to each other
- Many mitochondria
- Specialists of contraction & relaxation
- specialized to cause movement
- works antagonistically to carry out mechanical work
( striated/ striped/ voluntary)
- attached to bones & tendons
1. Muscle fibres lie parallel to one another
2. Voluntary co-ordinated movement of the skeleton
( unstriated/ unstriped/ involuntary)
- walls of internal organs
1. Spindle shaped
2. Nuclei twist when muscle contracts
3. Form continuous sheet
- Involuntary movement
- Contracts slowly
Movement of substances along internal passage ways
- walls of heart ( myocardium
1. Branched cells similar to skeletal
2. Ends joined by intercalated discs
3. Striated and can have more that one nucleus
- Involuntary movement
- Not subject to fatigue
Muscle bridge + intercalated bridge
What is nervous tissue?
- Made up of neurons
- transmit nerve impulses from sensory organs to the central nervous system
- from CNS to effector organs (muscles & glands) of body
What types of nerve tissue is there?
- Sensory neuron
- Motor neuron
- Inter/ connective neuron
Structure of nerve tissue
- Consists of a cell body, single prominent neuron & differentiated outgrowths
- Occur in cytoplasm of cell body
2. Mainly RNA & ribosomes -> plays a part in protein synthesis
Two types of nerve tissue outgrowths
- Dendrites - transmit impulses towards body
- Axon- transmit nerve impulses away from cell body
• only 1 axon but multiple dendrites according to function
- Series of consecutive cells that enclose the axon
2. Form a strong outer covering
- Neuron that occurs in peripheral nervous system
2. Produces myelin sheath
- Protective layer inside neurilemma
2. Insulator to prevent short circuit in nervous system
Nodes of Ranvier
- Gaps in the myelin sheath
- Myelin sheath & neurilemma are discontinuous
- nerve impulses move in one direction only
STIMULUS -> DENDRITES -> AXON
The site where a nerve impulse is transmitted from one neuron to the next
- there is no physical connection between neurons in this gap
- Special chemical molecules used to allow nerve impulses across synapse