TOPIC 5
ANIMAL TISSUE
• Highly developed cells = more specialised cells
• Tissue is formed by cells with a similar structure and function coming together
There are 4 types:
1. Epithelial tissue (squamous, cuboidal, columnar, ciliated, striated)
2. Connective tissue (dense, loose, uid)
3. Muscular tissue (voluntary, involuntary, cardiac)
4. Nerve tissue (sensory, motor, inter-neurons)
1. Epithelial tissue
• Forms linings of internal and external surfaces in the body (cavities, organs, ducts, passages)
• Tightly packed, barely intercellular air spaces, rest on basement membrane, normally single
layer (expect skin epithelium)
• Protects underlying tissue
• Squamous, cuboidal, columnar, ciliated, strati ed
a) squamous epithelium
Location:
Lines internal walls of cavities (blood vessels - endothelium, mouth, heart -
endocardium, oesophagus, alveoli)
Structure:
• Single layer of thin at cells
• Tightly packed - mosaic pattern
• Large, oval and attened nucleus
Function
• Protects underlying tissue
• Prevents friction
• Allows co2 and o2 pass through alveoli in lungs
• Allows substances in solution to pass through blood capillaries
fl fl fl fi
, b) Cuboidal epithelium
Location:
• Lines glands that secrete (thyroid, sweat, salivary) and absorb (renal tubules of
kidney) substances
• Embryonic epithelium (made of cuboidal) gives rise to ova (in ovaries) and sperm (in
testes)
Structure:
• Cube-shaped (square in section)
• Nucleus is round and in the centre
Function
• Protects underlying tissue
• Secretion (release useful substances)
• Absorption (take in useful substances)
c) Columnar epithelium
Location:
• Lines alimentary canal, small intestine, stomach
• Some perform sensory function in nose, ears, taste buds
Structure:
• Elongated, column shaped
• Nucleus is elongated, oval shaped at base of cell
• Goblet cells maybe present between cells
Function
• Protects underlying tissue
• Support other cells
• Absorption in small intestine (food, water, minerals), micro-villi increase surface area =
more absorption
• Secretion of protective mucus from goblet cells in digestive tract
• Sensation by sensory cells
d) Ciliated epithelium
Location:
Lines lungs and sensory organs (ears, nasal cavities, trachea, bronchi, uterus, fallopian
tubes)
Structure:
• Columnar epithelium with ne hairs (cilia) on free surface
• Cilla perform fast, rhythmical wave-like motions in speci c
a direction
• Goblet cells maybe present between
Function
• Protects underlying tissue
• In trachea, mucus from goblet cells, traps dust particles and is moved to pharynx by
cilia to be coughed or swallowed (avoids lungs)
• Detects stimuli in sensory organs
fi fi
ANIMAL TISSUE
• Highly developed cells = more specialised cells
• Tissue is formed by cells with a similar structure and function coming together
There are 4 types:
1. Epithelial tissue (squamous, cuboidal, columnar, ciliated, striated)
2. Connective tissue (dense, loose, uid)
3. Muscular tissue (voluntary, involuntary, cardiac)
4. Nerve tissue (sensory, motor, inter-neurons)
1. Epithelial tissue
• Forms linings of internal and external surfaces in the body (cavities, organs, ducts, passages)
• Tightly packed, barely intercellular air spaces, rest on basement membrane, normally single
layer (expect skin epithelium)
• Protects underlying tissue
• Squamous, cuboidal, columnar, ciliated, strati ed
a) squamous epithelium
Location:
Lines internal walls of cavities (blood vessels - endothelium, mouth, heart -
endocardium, oesophagus, alveoli)
Structure:
• Single layer of thin at cells
• Tightly packed - mosaic pattern
• Large, oval and attened nucleus
Function
• Protects underlying tissue
• Prevents friction
• Allows co2 and o2 pass through alveoli in lungs
• Allows substances in solution to pass through blood capillaries
fl fl fl fi
, b) Cuboidal epithelium
Location:
• Lines glands that secrete (thyroid, sweat, salivary) and absorb (renal tubules of
kidney) substances
• Embryonic epithelium (made of cuboidal) gives rise to ova (in ovaries) and sperm (in
testes)
Structure:
• Cube-shaped (square in section)
• Nucleus is round and in the centre
Function
• Protects underlying tissue
• Secretion (release useful substances)
• Absorption (take in useful substances)
c) Columnar epithelium
Location:
• Lines alimentary canal, small intestine, stomach
• Some perform sensory function in nose, ears, taste buds
Structure:
• Elongated, column shaped
• Nucleus is elongated, oval shaped at base of cell
• Goblet cells maybe present between cells
Function
• Protects underlying tissue
• Support other cells
• Absorption in small intestine (food, water, minerals), micro-villi increase surface area =
more absorption
• Secretion of protective mucus from goblet cells in digestive tract
• Sensation by sensory cells
d) Ciliated epithelium
Location:
Lines lungs and sensory organs (ears, nasal cavities, trachea, bronchi, uterus, fallopian
tubes)
Structure:
• Columnar epithelium with ne hairs (cilia) on free surface
• Cilla perform fast, rhythmical wave-like motions in speci c
a direction
• Goblet cells maybe present between
Function
• Protects underlying tissue
• In trachea, mucus from goblet cells, traps dust particles and is moved to pharynx by
cilia to be coughed or swallowed (avoids lungs)
• Detects stimuli in sensory organs
fi fi
