Jul . 1

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2012

Human biology -- tissues & organs

Features of muscle which are in common ---They are specialized for contractionThey all have contractile fibre which bound together by connective tissue which connects muscle with bones or skinThe energy need for contraction by muscles mainly comes from respirationBetween the muscle fibres an extensive network of blood capillaries runs Contraction of muscle fibre is caused by a complex re arrangement of its protein molecules

Involuntary muscle Found in the walls of the gut, blood vessels and bladderIt cannot be contracted at willControlled by unconscious mechanisms Its fibres are single cells which are elongated & pointed at each endThey control processes like peristalsis

Cardiac muscleFound only in the heartIt consists of single cells which are branched & joined together making a network of fibresIts fibre contract rhythmically with moderate speed throughout life, pumping blood around the body

Voluntary muscle Attached to the skeleton Can be contracted at will They consist of many cells & their structure is very complicatedThey can contract quickly & powerfully & causes movement of the body

Structure of involuntary muscle It has blood vessels & nerves Have nucleusIt has connective tissue Have muscle fibres [pointed at both ends]Have circular muscle & longitudinal muscle in small piece of gullet

Structure of cardiac muscle It is found in the heartHave one cardiac muscle cellThick cardiac muscle in the ventricle wall

Branched cells joints to form a network of contractile fibresStructure of voluntary muscle

Have nerve fibreHave blood vesselsOne voluntary muscle fibre

Jul . 1

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2012

Human biology -- tissues & organs

Have nerve endings on muscle fibres

Function of the ciliaCilia flick back and forth causing the movement of surrounding fluidsCilia carries dust and bacteria by away and protects the lungs

Functions of the epithelial tissue These tissues consists of sheets of cells which cover the external and internal surface of the body, and line the inside of the glandThis tissue covers the heart, lungs and other organs and lines the spaces in which the organs lie, reducing friction between surfaces which rub togetherThis tissue consist of glandular epithelium, which are specialized to produce useful substances like enzymes, mucus and hormones

Main function of the nervous tissue ---Conduct messages by a cell called nerve impulsesThis message are passed through neurons to response

Nerve impulses can be described as a travelling wave of electrical and chemical changes along a neurone as a result of stimulusCommon characteristics of all connective tissues

All consist of cells embedded in an intracellular substance called matrixFrom matrix cells produceThey connect tissues & organsProtect & support the organs and allowing them to move against one another

Aerolar tissues are found in the spaces between organsFunctions:

Consist of fibres &cells enclosed in a white sticky matrix which is produced by mast cells and these also produce heparin, a chemical which stop blood from clotting inside the blood vesselsFor this macrophage cells engulf & digest bacteria which enter wounds & can move through the matrix to infected areas

Differences between:Cartilage Bone It is a strong material but it is not brittle It is a hard substance and it is brittleIt is flexible tissue It is a connective tissueHave perichondrium Have periosteumNot so Have vein & arteryProduce wind pipe Produce blood cellsCartilage is found when the baby is started to its formation

Bone is found after the birth of a baby

Main functions of:Vertebral column ---

Jul . 1

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2012

Human biology -- tissues & organs

Attached to all vertebraeMovement of the vertebraeJoints with ribcage, skull &hip

Ribcage ---Protects the heart & lungsMaintains the shape of the bodySupports diaphragm muscle which is concerned with breathing

Skull ---Protects the brainProtects inner & middle ears & nasal organsSockets in there protects the eyes

Femur ---It is a thigh bone which consist of a long hollow shaftAnd also consists of two rounded ends or heads called epiphysisIt is long boneIt is called as appendicular skeletonIt allows the whole body to freely move at will

Function of each part of the bone:Epiphysis – it is sticky for which it rub against another bone at a jointDiaphysis – it is hard for which bone cannot break easilyPeriosteum – it protects the boneHard compact bone – gives the shaft its strengthBone marrow – fatty tissue in which blood cells are manufacturedSpongy bone – it consists sticky material for which epiphysis can do its work

Ossification is the process by which cartilage is transformed into bone during the growth of a babyA brief summary of ossification is given below:

Bone forming cells develop around the middle of a long bone’s shaft and form a thin cylinder of bone which supports the remaining cartilage as it is replaced by boneCartilage becomes saturated with calcium salts by a process called calcification. Cartilage cells then swell up and die leaving rows of empty holes Bone forming cells from the surface and blood vessels grows into the bone. They open up the rows of holes forming tunnels lengthwise along the bone. Bone forming cells lay down concentric rings of bone along the blood vessels forming bone tissue

Jul . 1

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2012

Human biology -- tissues & organs

A strip of cartilage remains between the shaft and the head of the bone because it helps to grow the bone and development of a body

Types of synovial joints and functions Ball and socket joint – allows movement in all directionsHinge joints – movement can occur only in one directionSliding joints – movement between vertebraePivot joint – occurs when one bone twists against another

Neural canal --- each vertebrae has an opening called neural canal through which the spinal cord passesIn brief, the neural canal provides space for spinal cord to occupy

Osteoblast --- cells which manufacture the bones

Chondroblast --- cells which manufacture cartilageFunctions of bones ---

Giving the body shape Assisting in movementProducing blood component cells from the bone marrowAnd even storing minerals such as calcium & phosphorus

The skeleton consists of:Bones [206]Cartilages Joints – also called articulations, junction between skeletal elementsLigaments – connect bones

Three types of muscle ---Skeletal [voluntary]Cardiac [involuntary]Smooth [involuntary]

2 types of bone tissue exist ---Spongy Compact

5 Types of connective tissue –Blood, loose, dense, cartilage, boneSynovial joint ---- any joint where there is a space between bonesMuscular system – component: skeletal muscle [contraction allows for voluntary movement]Functions of the muscular system ---Movement &locomotion, mechanical work [lifting, pulling, pushing objects], communication [body language & facial expression]Tension on tendons by muscles cause movement of the boneSkeletal muscle ---

Composed of individual muscle fibresContract when stimulated by motor neurone

Jul . 1

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2012

Human biology -- tissues & organs

Attached to bone on each end by tendons