Movement Locomotion In Animal

That branch of science which deals with bones and cartilage is called Osteology. Bones are made up of a protein called ostein and cartilage are made of a protein called chondrin. Hence study of bones is called osteology and study of cartilage is called chondrology. Body of animals (vertebrates) is supported by skeleton.

Movement distinguishes animals from plants. There are two aspects: (i) Locomotion (ii) Movement of body parts.

Locomotion, the movement of whole body, enables animals for various advantages like —

  • Shifting from unfavourable to favourable environment.

  • Moving away from enemy.

  • Locating food and shelter.

  • Searching partner for sexual reproduction and a safe place to lay eggs.

Movement of body parts serves many purposes like maintaining equilibrium of the body by changing its posture, intake and movement of food in gut, production of sound, generating sensory responses and collection of information, release of urine and faeces, circulating the body fluid and ventilation of lungs. The multicellular organisms including plants, exhibit also the type of movement shown by unicellular organism like, the ciliary and flagellar movement, amoeboid movement, cyclosis and cytoplasmic streaming.

The leucocytes (WBC) and phagocytes of animal tissue perform amoeboid movement.

The lining of ciliated cells in respiratory tract remove the dust and waste particles, move the gametes in the gonoducts (fallopian tube, vasa efferentia).

Sperms move by self flagellar movement.

Water current in the spongocoel (sponges) is generated by flagellar movement of choanocytes.

Machinery for generating movement in the organisms is of two types:

Tubulin-dynein system — Interaction of these proteins causes movement of cilia and flagella, chromosomes, neuronal transport, etc. In nerve axon kinesin is found in place of dynein.

Actin-myosin system — These proteins generate force/movement. e.g. the amoeboid movement, cyclosis, cytoplasmic streaming, cytokinesis and muscle contraction.

In higher animals movement of limbs and internal organs is generated by muscle, (filamentous actin and myosin) which move bones like levers.

Jelly fish, earthworm, leeches etc. have no skeleton but muscle like vertebrate’s smooth muscles and cardiac muscle is present.


  • Hydra being sessile animal performs all kind of locomotion like - walking, sliding, looping, somersaulting, floating, swimming, climbing, gliding, etc if required.

  • The epithelio-muscular cells in epidermis generate force at longitudinal axis of the body and nutritive muscular cells in gastrodermis generate force at circular axis.


  • In earthworm and leeches the contraction of longitudinal and circular muscles of the body wall pushs the body fluid (blood) in the direction of propagation moving the animal forward.

  • In polychaetes it is assisted by the structures like setae and parapodia.


The pressure in water vascular system causes tube feet to elongate and help moving over the surface.


The external movement is generated by the skeletal muscle associated with skeleton i.e. bones, cartilage of the body.


The hardened tissues of the body together form the skeleton (sclero = hard). Organism will remain small and slow moving if there had been no skeleton for support and to serve as levers on which muscles can act. Skeleton of invertebrates is most often secreted on the surface, forming a lifeless or dead exoskeleton. Whereas skeleton of vertebrates develops most often underneath the surface forming a living or growing endoskeleton. Three types of skeletons develop in vertebrates :

(i) Epidermal horny exoskeleton : These include hard and horny of keratinized derivatives of epidermal layer of skin, such as claws, reptilian scales, bird feathers and mammalian hairs, horns, nails and hoofs, etc. All living amphibians lack an exoskeleton.

(ii) Dermal bony skeleton : Dermal bony skeleton is derived from the dermis of skin. It includes bony scales and plates or scutes (osteoderms), finrays and antlers of fishes, reptiles and mammals. In fishes, dermal scales become exposed due to wearing out of epidermis, and form exoskeleton.

(iii) Endoskeleton : Greater part of vertebrate skeleton lies more deeply, forming the endoskeleton. It develops from mesenchyme. Endoskeleton is formed by bones in vertebrates.

a) Axial skeleton : It occupies the body's main longitudinal axis. It includes four structure : skull in the head, vertebral column in the neck, trunk and tail if present, sternum and ribs in the thorax. It form the upright axis of body and includes 80 (87 in children) bones are as follows in man –

Cranium – 8 Hyoid – 1

Face – 14 Vertebrae – 26 (33 in children)

Ear ossicle – 6 Sternum – 1

Ribs – 24


Skull is the endoskeleton of head and lies at the upper end of vertebral colunm due to erect posture of body. It is heaviest part of body. It consists of four portions the cranium, face, hyoid and sensory capsules. Skull is formed of 29 bones.

Cranium (Brain box). It is a large and hollow part of the skull which encloses and protects the brain in its cranial cavity. It forms the helmet for protection of brain. Size of cranial cavity ranges from 1450 to 1600 cm3 in adult man.

The cranium has a large opening, foramen magnum on its ventromedial side through which the brain is continuous with the spinal cord. It is so as skull lies perpendicular to the vertebral column. Human skull is dicondylic (with two occipital condyles on the sides of foramen magnum). Cranium is formed of eight bones:  

Sutures of skull. These bones are joined by immovable fibrous joints called sutures e.g. coronal suture lies between frontal and parietal bones, while lambdoidal suture lies between parietals and occipital bones. Sagital suture lies between two parietal bones

Functions of Skull of Man

  • It forms helmet for protection of brain.Fig. : Hyoid apparatus

  • Cranial cavity provides space for the brain.

  • A few skull bones form the sensory capsules that protect sense organs of head e.g. eyes.

  • Palatines support the hard palate.

  • Maxillae and mandible provide sockets for the attachment of teeth.

  • Facial bones form jaws for feeding.

  • Hyoid provides surface for the attachment of tongue muscles.

  • Ear ossicles help in hearing.

  • Exoccipital and sphenethmoid bones are cartilaginous, sphenethmoid is unpaired bone.

  • Pterygoid is the Y-shaped bone.

  • Zygomatic arch is found in upper jaw and formed by maxilla, squamosal and jugal.

  • The bones common to face and cranium are frontal.

  • Turbinal bones are present in the nasal passage.

  • Dermatocranium of skull comprises of membranous bone.

  • Turbinals bones are present in the nasal passage and increase the sensory surface of olfactory chambers.

  • Tympanic bulla enclosing the tympanus in mammal.

  • Coronoid process is a part of lower jaw in mammalian skull.

  • Lacrimal bone is situated infront of the eye orbit close to the frontal bone.

  • Mastoid bone is found in auditory region.

  • Frontoparietal is the membranous bone in frog.

  • Anterior cornua of the hyoid apparatus of frog articulate with auditory capsule.

  • Hyoid apparatus of frog is situated in the floor of pharynx.

  • Sella turcica is found in base-sphenoid bone. It is a depression in skull which lodges the pituitary body.

  • Amphibian & mammalia has dicondylic skull and reptiles, birds has monocondylic skull.

  • Alar process is a part of hyoid apparatus.

  • The hyoid apparatus of frog is entirely cartilaginous except posterior cornua.

  • Septum axillary in the paired bone in frog.

  • Pterygoid and palatines are paired bones on ventral side of skull of frog.

  • Hammer shaped bone in skull of frog is squamosal.

  • Pterygoid is membranous bone in frog skull.

  • Frog has no basisphenoid bone.

  • Vomers is paired dorsal bone in frog skull.

  • Lower jaw of frog includes mentomeckelian, dentary, angulo-splenial and meckels cartilage.


  • ”It is also call backbone. It is long (70 cm) curved bony rod present on dorsal side of neck and trunk.

  • Curves of vertebral column

  • ”It has cervical and lumbar curves directed forward, while the sacral and thoracic curves are directed backward. These curves especially the lumbar curve, help in erect posture of body and bipedal locomotion in man. Vertebral colunm of man is formed of 33 ring-like vertebrae. All the vertebrae are of amphiplatyan type, (Gr. am phi = both; platys flat; centrum flat on both sides). The vertebral formula of vertebral column of human being is C7 Th12 L5 S(5) Co(4) = 33, so vertebrae are divided in 5 categories.

                                  Differences between Osteoarthritis and Rheumatoid Arthritis



Rheumatoid Arthritis


Synovial membrane stops secreting synovial fluid.

Synovial membrane becomes inflamed.


Mainly affects weight bearing joints.

Usually starts at small joints in the hand and progresses centripetaly.


Smooth cartilage at the joints wears off and replaced by uneven bony spurs.

Joints get eroded.


Function of the affected joint gets diminished.

There is crippling deformity of the joints in volved.


Occurs in old age.

Usually occurs at the age of 20-40.

                                                Difference between Humerus and Femur







In upper arm of fore limb.

In thing of hind limb.



Fits in glenoid cavity

Fits in acetabulum.


Process on head

Two tuberosities.

Two trochanters.



With deltoid ridge.

No ridge


Lower end

With a pully-like trochlea having 2 epicondyles.

With two condyles and an intercondylar groove.

                            Important points of skeleton

                      Total number of bones : 206 Bones

Skull : 29 Bones

Cranium : 8 Bones

Occipital : 1 Bone

Parietal : 2 Bones

Frontal : 1 Bones

Temporal : 2 Bones

Sphenoid : 1 Bone

Ethmoia : 1 Bone

Facial region : 14 Bones

Nasals : 2 Bones

Vomer : 1 Bones

Terbinal : 2 Bones

Lacrymal : 2 Bones

Zygomatic : 2 Bones

Palaline : 2 Bones

Maxilla : 2 Bones

Mandible : 1 Bones

Coccyx : Fusion of 4 caudal vertebrae

In boy : 5 sacral vertebrae

In adult : Only one sacrum

RIBS in man : 12 pairs

True ribs : 7 pairs

False ribs : 3 pairs

Floatting ribs : 2 pairs

Vertebral formula = 33 (General)

C        TH L        S C


7          12 5        5 4

        Sacrum coccyx

In adult = 26

C        TH L        S C


7         12 5        1 1

        Sacrum coccyx

Ear ossicles

Mallus : 2 Bones

Incus : 2 Bones

Stapes : 2 Bones

Hyoid : 1 Bone

Vertebral column : 26 Bones

Sternum : 1 Bone

Ribs : 24 Bone

Pectoral girdle : 4 Bones

Pelvic girdle : 2 Bones

Fore limbs : 60 Bones (30 in each)

Hind limbs : 60 Bones (30 in each)

Total : 206 Bones

In child : Bones 300

  • Coracoid bone is vestigial in pectoral girdle of mammals, but is large sized in reptiles and birds.

  • Salla turcia : A depression in sphenoid bone of cranium of skull in which pituitary gland lies.

  • Obturator foramen : Large foramen between ishium and pubis bones of pelvic girdle.

  • Fibula : Thinnest bone of human body.

  • Number of bones in newly born body in 306.

  • Arthrology : Study of joints.

  • Shin bone : Tibia.

  • Reptilian scales; avian feathers and mammalian hair, nails, claw, horns and hoofs are homologous structures as all these are epidermal derivatives and formed of keratin.

  • All the reptilian vertebrae are procoelous.

  • Avian skull is characterized by papery bones and absence of sutures.

  • Pneumatic bones : Long bones of birds with air sacs e.g. humoral air sac in humerus.

  • Sternum in flying birds is keeled, but that of flightless birds is keelless.

  • Uncinate process : on the ribs of birds and join the ribs with one another.

  • Anterior fontanelle : A diamond-shaped, membrane covered soft area at the top of head of newly born baby.

  • Weberian ossicles : Modified vertebrae in carps and cat fishes. These connect air bladder and internal ear; and help in sound production.

  • Funny bone : A bone found in bend of the elbow.

  • Os penis : A bone supporting the penis of bats.

  • Os cordis : A bone supporting the heart of cattle.

    • Longest bone of frog is tibiofibula.

  • Nucleus pulposus : Soft core of intervertebral disc and represents the vestige of notochord in vertebrates.

  • Chondrology : Study of cartilages.

  • Red bone marrow is involved in the formation of erythrocytes and granular leucocytes, while yellow bone marrow is mainly involved in the fat storage.

  • Red bone marrow is present in spongy part (epiphyses) of bones, while yellow bone marrow is present in the shaft (diaphyses) of long bones.

  • Shaft of long bone is called diaphysis and has compact bone with yellow bone marrow while their ends are called epiphysis and have spongy bone with red bone marrow.

  • Bone forming cells are called  osteoblasts, while bone dissolving cells are called osteoclasts (with large amount of acid phosphatase enzyme).

  • Spongy bone is also called Cancellous or Tubecular bone, while compact bone is also called periosteal bones.

  • Astronauts pass out calcium in their urine due to faster breaking down of bones due to absence of gravitational pull.

  • Strongest cartilage is Fibro cartilage due to collagen fibres.

  • Osteoblasts are called bone forming cells, while osteocytes are called bone maintaining cells (control respiration, nutrition and excretion of bone cells).

  • Auditory or ear capsule is formed of periotic bone.

  • Osteoid is the uncalcified matrix of bone.

  • There are about 639 types of muscles in human body which form about half of body weight.

  • Contraction period of voluntary muscles fibre is 0.1 second, while it is of 3–180 seconds for smooth muscles. Contraction period for cardiac muscle is 0.8 second.

  • Longest smooth muscles are found in the wall of uterus of a pregnant female.

  • Smooth muscles of iris, ciliary body and hair muscles are in bundles.

  • Rigor mortis : Rigidity of muscles after death first seen in jaw muscles; starts seconds hour after death.

  • Vigor mortis : Rigidity of muscles due to deficiency of ATP in muscles.

  • In shivering, there is involuntary contraction of voluntary muscles to make the body warm as only 30-40% of energy released is used while rest of energy changes into heat.

  • Power of excitability is maximum in striated muscle fibres.

  • Degree of contraction of muscle is directly proprotional to number of motor units involved which in turn depends upon strength of stimulus.

  • Kymograph or Myograph. Instrument used to record single muslce twitch while its record is called single muscle curve  or myogram.

  • A muscle in contraction becomes shorter and thicker but its volume remains unchanged.

  • Thermopile : Instrument used to measure the heat produced during muscle contraction. It is about 18kcal of heat per hour at rest.

  • Single muscle twitch is also called springbok contraction.

  • Sliding filament theory of muscle contraction is also called Ratchet theory or walk along theory.

  • Cori’s cycle : It shows relationship between muscle glycogen and liver glycogen.

  • Isometric contraction : When during muscle contraction, muscle length remains same but tension increases e.g. Holding of some weight.

  • Isotonic contraction : When during muscle contraction, muscle length changes but tension remains constant e.g. during walking.

  • Glycogenolysis occurs in liver cells but not in muscle cells as these lack glucose-6-phosphatase enzyme.

  • Shivering : Involuntary contraction of voluntary muscles during which 30–40% of energy is used in contraction while rest of energy is chagned into heat which helps in warming of body.

  • Hypertrophy : Increase in size of a muscle by increase in number of myofibrils, mitochondria and sarcoplasm.

  • Lactic acid level in blood during muscle fatigue increases from normal level of 5mg/100 ml of blood to 150mg/100 ml of blood.

  • Tropism : Change in direction of a part of an organism in response to direction of a stimulus.

  • Taxis : Change in direction of a whole organism in response to direction of a stimulus.

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