Movement
Mechanisms and Roles
Movement in Plants and Animals
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Syllabus Objectives

Use examples to distinguish between growth
movement in plants and movements in animals
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Discuss the importance of locomotion in animals
Movement in Plants and Animals
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Movement is a characteristic of all living
organisms
It is a reaction to external or environmental
stimuli
It involves either part of the organism or the
entire organism (as in most animals)
The direction of the stimuli determines the
direction of the response
Movement in Plants and Animals cont’d

Locomotion is the movement of the entire
organism from one place to another

QUESTION

Based on the definition of locomotion, do plants and
animals exhibit locomotion?
Movement in Plants and Animals cont’d

Part movement in plants is a result of growth
as a response to various stimuli.

QUESTION

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Can you think of what stimuli plants respond to?
Growth responses in plants are usually slow
and are irreversible
Movement in Plants and Animals cont’d
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Movement in animals is usually faster than
growth in plants.
Movement in animals takes place in response
to a stimulus (much like growth movement in
plants)
These movements are however reversible

The organism or its part can return to its original
position when the stimulus is removed
Movement in Plants and Animals cont’d

Movement is important for the survival of all
organisms

QUESTION

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List the reasons why movement is important to animals
Finding food, finding a mate, escaping from
predators, finding a more favourable environment
These responses ensure that animals survive long
enough to produce new offspring
External Factors and Plant Movement

Syllabus Objective

Perform simple investigations to show how
external factors affect plant movement
External Factors and Plant Movement

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Growing plants respond to stimuli such as
light and gravity.
Movement towards a stimulus is a positive
response
Movement away from a stimulus is a negative
response
If a stimulus is applied from one direction, the
response is usually in one direction away
from or toward the direction of the stimulus
External Factors and Plant Movement
cont’d


The stimulus is received by the tip of the
shoot or root
The growth response takes place just behind
the tip

E.g. plant shoots will grow toward a light source.
External Factors and Plant Movement
cont’d
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Plant hormones called auxins are made at
the tips of roots and shoots
Auxins diffuse downwards and away from the
light source
Cells in the region where auxins accumulate
grow faster than other cells causing bending
in that region
External Factors and Plant Movement
cont’d

Different parts of the same plant may
respond differently to the same stimulus



Shoots respond positively to light
Roots respond negatively to light
QUESTION


Why would shoots respond to light positively?
Why would roots respond to light negatively?
External Factors and Plant Movement
cont’d

For Shoots



Light is essential for photosynthesis
Light is important for chlorophyll formation
For Roots

Light is not essential to root development or
growth
External Factors and Plant Movement
cont’d

Gravity


Shoots respond negatively to gravity
Roots respond positively to gravity

This response ensures that the root becomes firmly
anchored in the soil and is able to obtain water and
nutrients
Movement
Mechanism and Roles
Structure and Function of the Skeleton in
Man

Syllabus Objective

Relate the structure of the skeleton to its function
in man
Structure and Function of the Skeleton in
Man

The skeleton in Man

Rigid structure formed from


Bone and
Cartilage

It is located within the body and called an
Endoskeleton

QUESTION

What animals have a skeleton located outside its body?
Structure and Function of the Skeleton in
Man cont’d
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Bones are very strong and rigid
They consist of living cells surrounded by
hard mineral substances like calcium, some
carbonates and some phosphates
These mineral salts give the bones their
strength and shape
Spongy bone consists of a meshwork which
makes it very light
Dense bone is more solid and heavy
The general plan of the mammalian
skeleton

The skeleton of man is divided into two main
parts:

The axial skeleton

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
Skull
Vertebral column (backbone and spine)
Rib cage
The appendicular skeleton
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Pectoral girdles
Pelvic girdles
Bones in the arms and legs
The Axial Skeleton

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The skull is made up of several bones securely held
together
The vertebral column consists of several bones
called vertebrae
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Together they form a flexible rod running along the length
of the body
There are 4 distinct regions:

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Cervical or neck
Thoracic or chest
Lumbar or small of back
Sacral or lower back
The Appendicular Skeleton

The pectoral girdle consists of

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2 clavicles (collar bones) and
2 scapula (shoulder blades)
The pelvic girdle consists of

2 hip bones each made up of 3 bones tightly
joined together to form a bowl
The function of the skeleton

The skeleton performs several functions

Protection

Support

Movement and Locomotion

Blood Formation
Skeletal Function…Protection
Some soft tissues are protected by the skeleton

The skull protects
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the brain
Inner & middle ears
Nasal organs
The eyes
The vertebral column

The spinal cord

The Rib Cage protects

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Heart
Lungs
The Pelvic Girdle
protects

Reproductive organs in
females
Skeletal Function…Support

The skeleton forms a rigid framework which
maintains body shape.

The limbs support the body above the ground
Skeletal Function…Movement and
Locomotion

The bones

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The joints
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provide points of attachment for muscles and
Act as levers
Act as pivots
Muscles attached to bones contract and
movement occurs
Skeletal Function…Blood Formation

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Blood is produced in the red bone marrow
In children


red bone marrow is found in almost all bones
In adults

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the marrow in the shaft of long bones become
inactive
Blood formation is restricted to areas like

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The skull, the ribs
The sternum (breast bone) and vertebrae
Internet Links

http://www.zoology.ubc.ca/~biomania/tutorial/
bonesk/outline.htm
Joints, Muscles and Movement

Syllabus Objective

Describe the mechanism of movement in the limb
of man
Joints
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Joints occur where two or more bones meet.
Bones may be firmly attached to one another
so that movement of these bones is not
possible.
Such joints are immovable joints.
Most joints permit controlled movement of
bones and are called movable joints
Immovable Joints

Bones making up this type of joint are held
firmly in position

These types of joints exist between bones of
the skull and of the pelvic girdle

These bones protect organs that cannot
withstand being squashed or squeezed
Movable Joints

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The bones in these joints are separated by a
pad of flexible cartilage (gristle)
They may be of 2 types:


(i) slightly movable joints
(ii) freely movable joints
Movable Joints cont’d
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Slightly movable joints are found between
adjacent vertebrae
A pad of cartilage called the intervertebral
disc


Absorbs shocks and jolts transmitted to them
during running and jumping
Parts of these discs can be displaced through
poor posture or injury (slipped disc)
Movable Joints cont’d
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Movable joints have bones where they are
separated by synovial fluid
These joints are also referred to as synovial
joints
The synovial fluid lubricates the joints when
the bones move
The bones are held together by ligaments
Ligaments hold the bones firmly in place and
yet allow free movement at the joint
Movable Joints cont’d

Synovial joints are found at

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the elbow and knee (hinge joints) and
at the shoulder and hip joints (ball and socket
joints)
At the hinge joints, movement is restricted to
one plane only.
Movable Joints cont’d
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Each set of bones making up this joint
functions like one half of a hinge.
At ball and socket joints the rounded head of
one bone fits into a cup-shaped socket in
another
These joints allow movement in all planes
Movement
Mechanism and Roles
Terms you must learn

Ligament – connects bones

Joint – where bones meet

Tendon –connects muscle to bone

Synovial Fluid – acts as a lubricant
Joints, Muscles and Movement …Muscles

Muscle tissue consists of elongated cells or
fibres held together by connective tissue

There are 3 types of muscles in the body of a
mammal
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Involuntary (smooth) muscle
Cardiac (heart) muscle
Voluntary (skeletal) muscle
Muscle…

Involuntary muscle

Contractions of these muscles are usually slow
and rhythmical
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E.g. as in the digestive tract
Smooth muscle also control the movement of the
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Iris of the eye
The walls of the blood vessels
The walls of the bladder
Muscle…
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Cardiac muscle
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This type of muscle is found only in the heart
It has special properties

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It contracts without becoming fatigued for the whole life
of the organism
It does not need to be stimulated by hormones or nerves
to make it contract
Muscle…

Voluntary muscle

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Also called skeletal muscle because they are
attached to the bones.
They are under conscious (voluntary) control
Tendons attach muscle to bone

They are made of strong elastic fibres
Action at movable joints

Movements of the body occur when
contractions of voluntary muscles attached to
the bones of the skeleton take place

Each muscle is attached at 2 points and
crosses one or more joints which move when
the muscle contracts
Action at movable joints…

When a muscle contract, it becomes shorter
and exerts tension between its 2 points of
attachment

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One of these points remains fixed which is the
origin of the muscle
The other end moves as a result of this tension
and is called insertion
Action at movable joints…

Muscles can only contract and relax


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Contraction – muscles get shorter
Relaxation – muscles lengthen
All muscles act in pairs

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When one contracts the other relaxes
The contracting muscle lengthens the antagonistic
muscle which is relaxed


This produces movement of a bone in one direction
When the reverse happens the bone is moved in the
opposite direction
Action at movable joints…

There are times when both sets of muscle in
an antagonistic system contract at the same
time

This causes the joint to lock at a particular angle.
Action at movable joints…


During movement bones act as levers
Each joint acts as a pivot



Movement takes place at the joint
A force is applied when the muscle contracts
(effort)
The effort acts against another force (the
load)
Links
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