MOVEMENT
Ø Movement is the process of changing position or posture of an organism
Ø Movement in plants
involves growth response to a certain stimulus
Importance of movement in animals and plants
Ø Movement helps organisms to search for life necessities such as food, shelters, water and favourable
habitats
Ø It helps organisms to escape from unfavourable conditions such as high temperature (in plants), predators
Ø Movement also helps organisms to search for mates for reproduction
Ø It helps plants to grow towards gravity
to attain stability to the soil
Skeleton
The
hardest tissue of the body acting as framework to support and giving a particular shape to the body
Functions of the skeleton
Ø Protection: The skeleton protects all
the vital organs of the body.
Protects some internal organs from mechanical injury; for example the rib cage protects the heart and lungs
Ø
Support:
The skeleton forms a firm and rigid framework to provide support to the body like muscles
that are attached to bones move the skeleton.
Ø Movements: The skeleton provides firm
and hard surface for attachment of
muscles, which will move bones resulting in various movements.
Ø Formation of blood cells: The process of
haemopoiesis (formation of blood
cells) occurs at ends of long bones in bone
marrow.
Ø Respiration: The tracheal rings of
tracheas and ribs help in breathing.
Ø Storage: Bones act as reservoirs of
minerals and store fats in marrow
cavity. Provides a storage site for excess calcium. Calcium may be removed from bone to maintain a normal blood calcium level, which is essential
for blood clotting and proper functioning of muscles and nerves.
Ø Growth: The skeletal tissue permits
the growth of huge body size in animals like whale, elephant etc. ·
Ø
Shape:
The skeleton gives a definite shape to the body of every
organism
Human skeletal
system
Ø In human and other mammals movement is brought about by skeleton
and muscles
Ø Human skeleton is made up of skeletal tissues which are bones and cartilages
Types of skeletal
tissues
a. Cartilage
Ø This is a strong flexible tissue that gives shape to some parts of the body
Ø Simply cartilages are soft bones
Ø Cartilage also covers the end of some bones or make up discs between
vertebrae
Functions of cartilage
Ø Cartilage prevents bones from grinding
against each other
Ø It also forms the endoskeleton of some animals such as cartilaginous fishes (chondrichthyes)
Ø It also acts as shock absorber
for example between
the vertebrae
Ø There are also components of some
parts of the body such as pinna, trachea etc
b.
Bones
Ø These are hard and rigid tissues which are made up living tissues which are embedded in hard substances
made up of calcium salts and phosphates
Ø Bones usually develop from cartilage hence before birth bones are almost made of cartilage whose cell
absorbs calcium after birth to produce bones
Parts of human skeleton
The human
skeletal system is divided into two main parts
which is the axial and appendicular skeleton
The axial skeleton
The axial
skeleton lies in the midline of the body and consists of the skull, hyoid
bone, vertebral column, and rib cage.
The skull
Ø The skull is formed by the brain case, called
the cranium, and the facial
bones.
Ø
The cranium protects the brain, eyeball,
olfactory organs and is composed
of eight flat bones fitted tightly together in adults.
Ø In new-borns, certain
bones are not completely formed and instead
are joined by membranous regions
called fontanels.
Ø The fontanels usually
close by the age of 16 months.
Rib
cage
Ø
The rib cage is composed of the
thoracic vertebrae, the ribs and their associated cartilages, and the sternum
Ø The rib cage consists of flattened curved bones called ribs which articulates with the vertebral column to
the back and the sternum to the front
Ø There are 12 pairs
of ribs
Functions the ribcage
1.
Protection: Rib bones protect vital
organs in the chest cavity, including the heart
and lungs, from external impacts.
2.
Support: They provide structural support
to the chest, helping maintain its shape and integrity.
3.
Attachment for Muscles: Rib bones serve
as attachment points for various
muscles, including those involved in breathing and chest movement.
4.
Respiratory Muscle Attachment: Muscles
such as the intercostal muscles
attach to the ribs and play a direct role in expanding and contracting the chest during breathing.
5.
Movement Facilitation: They assist in
the flexibility and mobility of the chest
wall during inhalation and exhalation.
6.
Contribution to Posture: Rib bones
contribute to maintaining an upright
posture and stability
of the upper body.
Types of Ribs:
Explain the differences between true ribs, false ribs,
and floating ribs, and how they are numbered.
True Ribs, False Ribs, and Floating Ribs differ in their attachment to the sternum and how
they are numbered:
True Ribs
Ø Attach directly to the sternum
via individual costal
cartilages.
Ø Numbered as the first seven
pairs (ribs 1-7).
Ø
Provide structural support and protection to the chest
cavity.
False Ribs
Ø Indirectly attach to the sternum via shared or connecting cartilages.
Ø Include pairs 8-10 (ribs 8-10).
Ø
Ribs 8-9 have their cartilages
attached to the cartilage of the rib just above.
Ø Rib 10 has its cartilage
that attaches to the cartilage
of the rib just above and often joins with rib 9's cartilage.
Ø Offer less direct
support to the sternum but contribute to chest wall integrity.
Floating Ribs
Ø Lack direct attachment to the sternum.
Ø Comprise the last two pairs,
ribs 11 and 12.
Ø Their costal cartilages do not connect
to the sternum or to other ribs.
Ø Provide minimal structural support but protect the kidneys and flank area.
Ø The human vertebral
column is also called
the back bone
Ø The vertebral column consists of 33 vertebrae which stretch from the base of the skull to the pelvis
Ø Between two adjacent vertebrae is a cartilage called intervertebral disc which acts as a shock absorber
Ø The main functions of the vertebral column is to support the trunk and protect the spinal cord against physical
damages
Ø The vertebral column has five types of vertebrae namely cervical vertebrae, thoracic vertebrae, lumbar vertebrae, sacral and caudal vertebrae
The functions of vertebral
column
Ø It allows the human being to stand
upright and maintain
balance
Ø It supports the head
Ø It protects the spinal cord
Ø It provides attachment to ribs and muscles
Types of vertebrae in vertebral column
1. Cervical vertebrae
Ø These are short bones found in the neck region of which there are 7 vertebrae which form the skeleton of the neck
Ø The first two cervical vertebrae are called atlas and
axis respectively which
are modified to permit the movement of the head
Adaptations
of the cervical vertebrae
Ø Have branched transverse
process to provide large surface area for attachment of muscles
Ø Have wide neural canal for passage
of spinal cord
Functions of the cervical
vertebrae
Ø It provides support
to the skull
Ø
Allows free rotation and nodding of the head
Ø
It provides attachment for neck muscles
2.
Thoracic vertebrae
Ø These are found in the thoracic region. They are 12 and articulate with the ribs to the back and sternum to the front
Ø The thoracic vertebrae together with the ribs and sternum form the rib cage
Functions
Ø It provides support
to the ribs
Adaptations
Ø They have long neural spine to provide the surface area for attachment of muscles
Ø They have wide neural
canal for the passage of spinal cord
3.
Lumbar vertebrae
Ø This is a type of vertebrae which is found in
the lumbar region
Functions
Ø It permits bending,
sideways movement and rotation of the
trunk
Ø
This is the region where most
of muscles of the stomach are attached
Adaptations of Lumber vertebrae
Ø Have long transverse process to increase the surface area for attachment of abdominal muscles
Ø They have wide neural
canal for the passage of spinal
cord
4.
Sacral vertebrae
Ø These are found in the sacral region which are fused together
to form a sacrum
Ø The sacrum provides
the large surface
area for attachment of muscles of the back
The appendicular skeleton
Ø The skeleton present on lateral side of median axis of the body are called
appendicular skeleton
Ø
It consists of
appendages and limbs which are attached to the axial skeleton
Girdles
Ø
Girdles are endoskeleton parts through which fore limbs and hind limbs are attached to other body parts.
Ø
Girdles may be attached
indirectly or directly
to vertebral column
these are of two types;
Pectoral Girdle
Ø Pectoral girdle is a skeletal frame work of the body, located in shoulder region. It may be attached indirectly through muscles
and ligaments (in higher vertebrates).
Ø The pectoral girdle
joins forelimbs or pectoral
fins with the body.
Pelvic Girdle
Ø Pelvic girdle is skeletal framework
of body located
in hip region.
Ø It consists of two separate
pieces which may articulate with each other and overlap.
Ø Pelvic girdle is used for articulation/attachment of hind limbs
Fore limbs
Ø These are attached
to the axial skeleton to the anterior
part of the body
Ø Fore limbs consist
of the pectoral girdles, Humerus,
ulna, radius, carpals, metacarpals and phalanges
Hind
limb
Ø Hind limbs are attached to the axial skeleton to the posterior
part of the body
Ø It comprises of the pelvic girdles, femur, tibia, fibula, tarsals, metatarsals and phalanges
Joints
Ø A joint is a point where a bone meets another bone or bones. Or Joints
are regions of articulations between
bones.
Ø Movement of skeletal elements over each other is only possible if there is a joint
between them
Ø Bones of mammalian skeleton are joined to one another
in different parts
of the body in order
to allow movements of the body parts
Fixed or immovable joints
Ø These are joints
which do not allow any movement
Ø They are found
in the cranium and are commonly called
sutures
Ø Fixed joints are also found
in the pelvic girdles
Movable joints
Ø These are joints that allow movement of the body parts to take place
Ø Some movable joints allow only small degree of movement
and are called slightly movable joints while some joints allow a wide range of movement
and hence are called freely movable joints
Examples of movable joints are knee joints, neck joints and pelvic joints
o Consider a table below
|
Category of
joint |
Type and description |
Examples |
|
Immovable |
Suture—fibrous connective tissue between bone surfaces of a skull |
Between cranial bones; between facial
bones |
|
Slightly movable |
Symphysis—disc
of fibrous cartilage between bones |
Between vertebrae; between pubic
bones |
|
Freely movable |
Ball and socket— movement in all planes |
Scapula and humerus; pelvic bone and femur |
|
Hinge—movement in one plane |
Humerus and ulna;
femur and tibia; |
|
|
Pivot—rotation |
Atlas and axis;
radius and ulna |
|
|
Gliding—side-to-side movement |
Between carpals |
|
|
Saddle—movement in several planes |
Carpometacarpal of thumb |
Gliding joints
Ø These are joints
that occur between
the vertebrae
Ø These joints have no fluid between them instead they have a large cartilage called intervertebral disc
which reduce friction during movement
Ø Intervertebral disc also acts as a shock absorber
Ø Gliding joints are also found in
the wrist and ankle
Hinge joints
Ø These are joints which allow the movement in one plane (direction) like the door
Ø Examples are elbow and
knee joints
Ø In a movable
limb joints the bones are joined to one another
by strong fibrous
tissue called ligament
Ø The ligament is lined with a thin membrane called synovial
membrane which secrete synovial
fluid
Ø Synovial fluid forms a film between the articular surfaces
and help to lubricate them
Ball and socket joint
Ø
These types of joints
allow the greatest
flexibility of movement
of all joints
Ø These joints involve two bones, one with rounded head and the other with a depression into which the
head of the first bone fits and move freely
Ø Examples of ball and socket joints include hip joint and shoulder joint
Ø Some joints have synovial fluid which reduces
friction by lubricating the bones, such bones are referred
to as synovial joints
Ø Synovial joints include
hip joint, shoulder
joint and knee joint
Ligament
This is a
fibrous tissue which joins one bone to another. These are elastic
to allow movement at a joint
Tendon
This is a tough
connective tissue which attaches muscles to bones They are inelastic
to firmly attach muscles
to the bones
Pivot joint
Ø This is a type of joints which only allows
the rotation of the bones
Ø
Example the joint between the
radius and ulna and a joint between atlas and axis in the neck
Sample Question
1.
You have been provided with
mammal’s bone A, B, C and S, T, U
of fore limb and hind limb. Examine carefully and answer the following
questions.
a)
Identify each bone A, B, C and S,
T, U by their names
b)
Mention the bones which are of
fore limb and hind limb
c) Give the main function of the bones S, T and U
d)
How each bone S, T and U adapted
to its function?
e) Name the various joints
formed between bone A, B and C
f)
Using diagrams show the
structures of various bones that you have observed.
g) What are the structural differences between bone B and
C?
h)
Give any four bones
in which red blood
cells are formed.
i)
What is the name of the softy and fatty
tissue inside of the bone S, T
and U?
j)
What is the name and
functions of long protrusion at the end of
bone
C?
2.
You have been provided with
bone bones X and Y observe carefully and answer the following
questions
a)
Give the name of bones provided
b) Give the function
of bone X
c)
What are the adaptations of bone X to
its function?
d) Draw a well labelled diagram of bones X and give the functions of the labelled
parts
e)
How many pieces of bone Y comprises in the body of mammals?
f)
There are three types of bone Y in mammals name them with their meaning
g)
Why bone why also known as thoracic ribcage?
h)
What are the main functions of bone Y?
