bioscience week 1 practical

Cells closely packed together

very little intercellular material

Just 1 layer of flattened cells

thinnest possible tissue 

Found whereever a very thin barrier is needed to facilitate diffusion of materials

e.g. alveoli, capillary walls

More than one layer of cells

Transitional epithelium is found in the bladder and has the ability to strech when bladder is full

Stratified Squamous epithelium 

very many layers of cells which are constantly regenerating from bellow, making it a good protecting tissue found in skin, oesophagus and rumen

Exocrine glands secrete hormones into a duct 

Endocrine glands have no duct and secretions of digestive enzymesbut also sweat and mucus pass directly into blood

Usually only a few scattered cells but large amounts of intercellular material

Main function of the blood is to transport a range of materials around the body but also defends body against disease.

Areolar connective tissue acts as "packing" tissue and fills in the spaces between the organs suchas attaching the skin to the underlying muscle, connecting up various loops of intestine 

very diffuse tissue and looks like "bubbly cellophane"

Adipose tissue (fat) is found under the skin, around heart and kidneys and within skeletal muscle. acts as insulator, protects against mechanical damage and is an energy store

Many fibres are present both elastin and collagen elastin fibres can strech and then return to their original length, while collagen fibres do not strech but are extremely strong.

Made of collagen fibres which are dense bundles of white fibres.

Tendons are found joining a muscle to bones

where they are transfering movements and pull bones

found joining bone to bone

it is slightly elastic ie it can stretch as bones move.

intercellular material composed of a protein called chondrin allowing oxygen and nutrients to diffuse through it enabling rapid growth.

it is more flexible than bone which helps the foetus as it is pushed through the mothers pelvic girdle at birth

found in trachea to keep it permanently open and allow the passage of air in and out.

Found on the end oof long bones because its is smooth and slippery so it is acting as a solid lubicant preventing bones from rubbing on other bones in a joint.

Each group of bone cells surrounds a central canal containing blood vessels which supply the living cells

the bone supports the body and form a foundation for skeletal muscles to bring about movement, protect especially vulnerable organs. bones also store ,minerals

Skeletal muscle is found attached to the skeleton and its function is to contract and bring about movement. it is striated and the fibres run parallel

cardiac muscle is found in the heart. its structure is branched and the fibres run parallel. it is also striated. unlike skeletal muscle which is voluntary, cardic muscle is involuntary

Smooth muscle is found in the walls of the digestive, reproductive, urinary and respiratory as well in all blood vessels exept capillaries. the cells are long thin spindle shaped with no stripes. like cardiac muscle there function is also involuntary and not under coscious control.

2 main parts;

Cell body- receives and assesses information

Axon- transmits information

myelinated nerves have an axon covered in a myelin sheath

Myelinated nerves can transmit impulses faster than non myelinated nerves and so are found in the limbs and trunk of animals i.e. cover long distances.

non myelinated nerves are found within the brain and spinal cord where distances are shorter.