Upload
others
View
4
Download
0
Embed Size (px)
Citation preview
Introduction to Movement and Locomotion
Movement is one of the things that differentiates a living thing from a
non- living thing. When we speak about locomotion and movement,
we often use one for the other. But, it is important to understand the
difference between the two in relation to living things.
Locomotion and Movement
Movement is when the living organism moves a body part or parts to
bring without a change in the position of the organisms. Locomotion
is when the movement of a part of the body leads to change in the
position and location of the organism. Both of these are brought about
by the joint efforts of the skeletal and muscular systems. Movement is
seen in both vertebrates and invertebrates.
Browse more Topics under Locomotion And Movement
● Muscle
● Skeletal System
● Joints
● Disorders of Muscular and Skeletal System
Types of Movements
When we talk about locomotion and movement, there are three types
of movements:
● Amoeboid movement is brought about by pseudopodia which
are appendages which moves with movement of protoplasm
within a cell.
● Ciliary movement is brought about by appendages called as
cilia which hair-like extensions of the epithelium. Both these
kinds of movements are seen with cells of the lymphatic
system.
● Muscular movement is a more complex movement which is
brought about by the musculoskeletal system. This type of
movement is seen in the higher vertebrates. To understand
more about the movements brought about by the
musculoskeletal system, we need to understand the types of
muscles, and joints.
Types of Muscles
Muscles found in higher vertebrates are of three types:
● Striated or skeletal muscles
● Unstriated or smooth muscles
● Cardiac muscles
(Source: Blogspot)
Striated or Skeletal Muscles
These muscles are voluntary in nature which means their movement is
under the control of our will. They are mainly responsible for bringing
about the movement of posture and location of the organism. They are
called striated muscles due to the presence of striations present on
them when seen under the microscope.
Unstriated or Smooth Muscles
These muscles are involuntary in nature which means their movement
is not under the control of our will. When seen under the microscope,
they do not have any striations on them. These muscles are found in
the digestive tract and reproductive system.
Cardiac Muscles
These muscles are specialized muscles that are found only in the heart.
They are involuntary muscles which have striations on them. They
have the property to contract and relax in a rhythmic manner.
Skeletal System
The skeletal system is made up of bones and cartilages. There are a
total of 206 bones in the body. They are divided into the Axial
skeleton and the appendicular skeleton.
The axial skeleton consists of bones that are found towards the center
of the body including the skull, the vertebrae, and the sternum. The
appendicular skeleton consists of bones that are found in the
extremities.
Joints
They form an integral portion of the locomotive apparatus. A joint is a
name given to two or more bones that articulate with each other to
bring about a movement. Depending on the type of movement they
allow, joints can be of three types: Fixed, slightly moveable and
moveable joints.
Solved Example for You
Q: What kind of muscles are found in the reproductive system?
a. Cardiac Muscles
b. Striated Muscles
c. Skeletal Muscles
d. Smooth Muscles
Sol: Correct answer is (d) Smooth muscles
Reproductive system has smooth or involuntary muscles that are not
under the control of our will.
Muscle
The muscular system along with the skeletal system forms the
skeletomuscular system that is responsible for the movement and
locomotion in vertebrates. The unit of the muscular system is called a
muscle. Muscles are made up of proteins and fibres and form the
major component of the body weight.
General Structure of a Muscle
(Source: SEER Training)
Each muscle (mainly skeletal) has an outer covering called the
perimysium. It covers and protects the muscle fibres. Around the
entire structure lies the fibrous layer of the epimysium which protects
the entire muscle. Each bundle of fibre is known as a ‘fascicle’. And
each fibre is covered by the endomysium.
Browse more Topics under Locomotion And Movement
● Introduction to Locomotion and Movement
● Skeletal System
● Joints
● Disorders of Muscular and Skeletal System
Types of Muscles
Skeletal Muscles
These are found throughout the body where conscious movements are
performed. They are attached to bones through a structure called as
the tendon. We find them around joints so that they bring about
movements in that part of the body. For this reason, skeletal muscles
are also known as voluntary muscles.
The skeletal muscles are very specialized in their structure and
function. Each is made up of many fibres. Each skeletal muscle fibre
is made up myofibrils which are made up of smaller units called as the
sarcomere. The cell membrane of these fibres is known as the
sarcolemma. These muscles are also rich in mitochondria which are
required to help each muscle fibre cell perform the activity of the
muscle. From the sarcolemma, there are tubular extensions known as
the T- tubules which conduct electrochemical impulses from the outer
membranes to the centre of the muscles. Muscles are made up of
proteins- actin, myosin, and troponin.
Skeletal muscles are named in different ways: Some are named
depending on their location, some depending on their origin or
insertion, some based on the number of origins of a single muscle and
others on basis of their direction and function.
Smooth Muscles
These are also called as involuntary muscles as they are not under the
control of our will. They are found in the visceral organs and so are
also known as visceral muscles. They do not have striations when
viewed under the microscope like the skeletal muscles and so they are
called as smooth muscles. Smooth muscles are found in the digestive
system, reproductive system, urinary system and are also found in the
blood vessels.
Cardiac Muscles
These are striated involuntary muscles that are specialized to perform
rhythmic contraction and relaxation and are found only in the heart.
The cells of the cardiac muscles are branched and connected to
adjacent cells via connections known as the intercalated disc. This
branching along with the striations make these muscles strong and
resilient to withstand demanding activity from the entire body. The
branching also helps in quick transmission of signals to enable the
heart to respond fast.
Solved Example for You
Q: What is the covering of the individual muscle fibrils called?
a. Endomysium
b. Epimysium
c. Fascia
d. Perimysium
Sol: The correct answer is (a) Endomysium
Endomysium covers the individual muscle fibres. Epimysium covers
the entire muscle while the perimysium covers the muscle fibre
bundles.
Skeletal System
Did you know that newborn babies have around 305 bones! A baby’s
skeleton is mostly made up of cartilage. As it grows older cartilage
undergoes ossification to form a complete skeletal system, having 206
bones. Let us learn about a human skeletal system.
Parts of the Skeletal System
(Source: Britannica)
The skeletal system is made up of bones and cartilage. There are two
types of connective tissues called tendons and ligaments that are also
considered a part of the system. Ligaments connect bones to bones
whereas tendons connect bones to muscles.
The two main parts of the skeletal system, as mentioned above, are
bones and cartilage.
Bones
There are 206 bones in the body which form more than 200 joints with
each other. They are classified into two broad categories based on
location:
● Axial skeleton: These bones are found towards the midline of
the body and include the skull, the rib cage, and the vertebral
column.
● The appendicular skeleton: These bones are found in the
appendages such as arms, legs fingers, and toes.
Bones can be classified into four types based on their shape:
● Long Bones -They are long and slender bones found generally
in the limbs. ex. humerus, femur.
● Short Bones: They are short bones which are smaller in size
and are found in the carpals and tarsals.
● Flat Bones: they are thin and flat in nature and not all of them
are completely flat. They provide surface area for muscle
attachment. Ex: scapula, sternum
● Irregular Bones: These bones do not have specific shapes and
therefore cannot be put into any other group. Ex: vertebrae
Structure of a Bone
Lets now see what the structure of an individual bone looks like.
(Source: http://lyceum.algonquincollege.com/)
Each bone tissue is made up of two types of osseous tissue: compact
bone and spongy bone.
Compact bone is hard and compact in nature and always found
towards the outside of the bone whereas the spongy bone which is
softer and more porous is found towards the centre. The function of
each bone determines the ratio in which these two types of tissues
exist within it.
The connective tissue that is found on the outside of the bone is
known as the periosteum. The periosteum is made up of cellular and
fibrous tissue and plays a crucial role in the attachment to muscles and
joints as it is this layer which contains tendon and ligament
attachments. The endosteum is the connective tissue layer which lines
the marrow cavity.
Browse more Topics under Locomotion And Movement
● Introduction to Locomotion and Movement
● Muscle
● Skeletal System
● Joints
● Disorders of Muscular and Skeletal System
The shaft of a bone is known as the diaphysis and the swollen end is
called the epiphysis. The epiphyseal line demarcates the two parts. It
is the diaphysis which houses the marrow cavity which is majorly
composed of loose connective tissue and is responsible for producing
blood cells.
The cells that form bone matrix are known as osteoblasts and the
mature cells of the bone are called osteocytes. There is a special type
of cells that help remove bone matrix and are found during bone
remodelling known as osteoclasts. These are gigantic cells and are
always found on the side of the bone where the matrix is being eaten
away during growth and remodelling.
The matrix in a bone tissue is made up of two components: the organic
part that contains fibres whereas the inorganic part consists of the
minerals(hydroxyapatite).
Learn more about Disorders of Muscular and Skeletal Systems.
Cartilage
Cartilage is the second component of the skeletal system. It is made up
of fibres that are embedded in connective tissue or ground substance.
Cartilage consists of two types of fibres: Collagen and elastin fibres.
The cells that form cartilage are known as chondroblasts and the
mature cells of the cartilage are known as chondrocytes.
The chondrocytes lie in lacunae in the matrix. The outer layer of a
cartilage is known as the perichondrium. Unlike the bone, cartilage is
avascular which means that it contains no blood supply. However, the
perichondrium contains blood supply. There are 3 types of cartilages
namely Hyaline cartilage, elastic cartilage, and fibrocartilage.
● Hyaline cartilage– the most abundant of the three cartilages and
functions to help surfaces slide over one another. Example:
found in the respiratory system.
● Fibrocartilage– This cartilage is tough and its main function is
to provide support and strength to structures. Example: found
in healing tissue during bone repair(callus)
● Elastic cartilage– This cartilage is abundant in elastic fibres and
functions to maintain the shape of the area it is present in.
Example: found in the middle ear.
Functions of the Skeletal System
● The main function of the skeletal system is that it provides a
framework to the body and provides shape.
● Along with the muscular system, the skeletal system helps in
the movement of the body parts of the body and locomotion of
the body.
● The skeletal system is hard and so forms a protective layer for
the softer, more delicate organs from any form of injury. The
rib cage protects the heart, lungs and visceral organs, the brain
is protected by the skull etc.
● It is the growth and development of bones that provides the
height and width of an individual.
● The centre of the bone consists of the bone marrow which
produces blood cells and therefore hemopoietic in nature.
Solved Example for You
Q: The connective tissue on the outer surface of a bone is called as?
a. Endosteum
b. Epiosteum
c. Perichondrium
d. Periosteum
Sol: The correct answer is (d) Periosteum
The connective tissue layer on the outer surface of a bone is known as
the periosteum. The connective tissue layer that is found lining the
marrow cavity in a bone is known as the endosteum. Perichondrium is
the outer layer of a cartilage. Epiosteum is not a structure found in
either cartilage or bone.
Joints
Joints aka articular surface can be defined as a point where two or
more bones are connected in a human skeletal system. Cartilage is a
type of tissue which keeps two adjacent bones to come in contact (or
articulate) with each other. 3 Types of joints are Synovial Joints,
Fibrous Joints, and Cartilaginous Joints. Joints help in bringing about
movements in different parts of the body. Let us see the classification
of joints and anatomy of different types of joints.
Classification of Joints
Joints can be classified in different ways depending on:
a. The amount of mobility permitted by the joints
b. Type of tissue connecting the bones
Each of these types can be further subdivided. Let’s look at each
classification individually.
A] The amount of mobility permitted by the joint
(Source: TeachPE.com)
Depending on the degree of mobility permitted by the joint, we can
classify them as:
● Fixed Joint or Synarthroses– The word ‘syn-‘ tells us that the
bones are fused and therefore permit minimal or no movement.
These joints are fibrous joints which means that the binding
tissue between two bones is ‘fibrous’ in nature. Example of a
fixed joint is the sutures between skull bones.
● Slightly Movable Joint or Amphiarthroses– This joint permits
slight mobility that is more than what is seen in a fixed joint.
The binding tissue in this type of joint is cartilaginous in
nature. Example of a slightly moveable joint is those found
between intervertebral discs.
● Freely Moveable Joint or Synovial Joints– These joints permit
maximum movement between the bones involved. They are
also called as ‘diarthroses’ and are further classified into 6
types depending on the kind of movements possible.
Types of Synovial Joints
(Source: opencurriculum.org)
● Ball and socket joint– This kind of joint involves two bones.
One of the bone has a large rounded end which fits into a
cup-like socket of the other bone. This kind of joint is generally
found in large bones such as the shoulder joint and hip joint. A
ball and socket joint provides the greatest degree of movement
among different kinds of joints including rotation, flexion,
extension, abduction, and adduction.
● Hinge joint-This joint is said to be a very simple joint that
allows movement only in one axis. It allows only two kinds of
movements- flexion and extension. Example of this joint is the
joints found between in the elbow and knee.
● Pivot joint– This type of joint allows rotation along one axis
only. A common example of this type of joint is the
atlantooccipital joint in the neck.
● Ellipsoid/gliding joint– This joint is very similar to the ball and
socket joint but without rotation. It allows movements only in
two axes. Example of this is the wrist joint.
● Saddle joint– It is similar to an ellipsoid joint which involves
two bones- one of the bones has a convex surface while the
other has a concave surface. The convex surface of one bone
articulates with the concave of the other to allow limited
rotational movement. A very classic example of this kind of a
joint is the carpo-metacarpal joint in the thumb.
B] Type of Tissue Connecting the Bones
Based on the type of tissue connecting the bones, we can classify
joints as:
● Fibrous– The tissue connecting the two bones is fibrous in
nature
● Cartilaginous– Cartilage forms the connecting tissue between
two or more bones
● Synovial– The two bones form a synovial cavity with synovial
fluid which forms the connecting tissue
Apart from movement and locomotion, joints also help stabilize the
different parts of the body.
Solved Example for You
Q: What kind of a joint is in the wrist?
a. Saddle Joint
b. Pivot Joint
c. Gliding Joint
d. Ball and Socket Joint
Sol: The correct answer is (c) Gliding Joint
This joint allows movement only in two axes and is found in the wrist
joint between the radius, scaphoid and lunate bones.