Joints, Muscles And Reflexes

Question 1

What are different types of joints

Answer 1

Fiberous joints
Cartilinginous joints
Synovial joints including ball & socket, hinge, gliding, pivot, condyloid and saddle

Question 2

What are the common features of synovial joints

Answer 2

Articular cartilage
Joint capsule
Synovial membrane
Synovial fluid

Question 3

Describe articular cartilage

Answer 3

Coats the two bones that meet each other
Provides a smooth surface reduces friction and distributes weight easily
Gets thinner with age

Question 4

Describe joint capsule

Answer 4

Joint is wrapped in a sleeve of fibrous tissue that holds the bones together

Question 5

Describe the synovial membrane

Answer 5

This delicious epithelial layer lines the capsule and covers all non- weight- bearing surfaces inside the joint
Secretes synovial fluid

Question 6

Describe synovial fluid

Answer 6

Thick sticky fluid that fills the cavity
Contains phagocytes to keep joint healthy
Lubricates the joints
Aids movement
Maintains stability prevents friction

Question 7

Describe fibrous joints

Answer 7

Bones forming these joints are linked together with tough fibrous material
Means that often the joint is unable to move such as in the skull
In some bones the fibrous joint allows for limited movement e.g. in intraosseous membrane between tibia and fibula
This material limits movement however and strengthens the bone

Question 8

Describe cartilaginous joint

Answer 8

Tough fibro cartilaginous material binds the bones together
In some cases the material allows no movement- epiphyseal plate
But in others it allows limited movement e.g. vertebrae and pubic symphysis
The pubic symphysis softens in pregnancy in response to hormone production allowing the pelvis to expand

Question 9

Describe the muscles and the 3 types

Answer 9

Essential to facilitating skeletal movement
Also keep heart beating
3 types of muscle tissues - smooth, cardiac and skeletal

Question 10

Describe skeletal muscle

Answer 10

Is anchored to bones via tendons
Under voluntary control ( although there are occasions due to reflexes where it’s involuntary)
Is striated in appearance

Question 11

Describe muscle tissue

Answer 11

Very large, cylindrical in shape and lie parallel to each other
Gives it unique banded appearance
Can run the entire length of the muscle ( up to 35cms ) in the largest muscle
Made up of many rows of fibres which are made up of bundles called fascicles
Each bundle is covered with a tissue sheath called perimysium
Within the fascicles the individual muscle fibres are wrapped in endomysium

Question 12

Describe the muscle cell structure

Answer 12

Cell membrane of a muscle cell called sacrolemma
Cytoplasm of muscle cell called sacroplasm
This is threaded through with tiny thread like fibres called myofibrils
Have large amounts of mitochondria
Also produce myoglobin which is similar in nature to Hb and helps muscle cells store O2 within the cell
Myofibril contains two contracting protein called actin ( thin ) and myosin ( thick )

Question 13

Describe reflexes

Answer 13

Are fast up to 320mph
Occur over simple nerve pathways called reflex arcs
Involuntary and usually protective motor towards specific stimuli
E.g. withdrawal of hand from a hot surface

Question 14

Describe the reflex arc

Answer 14

Composed of :
- receptor
- sensory neuron
- integration centre - synapse in CNS
- motor neuron
- effector

Question 15

What is reflex testing

Answer 15

Important diagnostic tool for assessing the condition of the nervous system
Distorted, exaggerated or absent reflexes may indicate damage to nervous system
Reflex tests may determine the area of injury to the spinal cord
Some reflex tests may indicate damage to the brain

Question 16

Describe the involuntary reflexes

Answer 16

Corneal - eye close, when conjunctiva or eye lashes are touched
Cough reflex - nerve endings in the larynx, trachea and bronchi are sensitive to irritation which generates nerve impulses conducted by the vagus nerve to the respiratory centre in the brain stem = reflex is deep inspiration and closure of the glottis, abdominal and respiratory muscles contract = sudden and rapid pressure in the lungs
Glottis opens expelling air, mucus out the mouth

Question 17

Describe the Hering- Breuer reflex

Answer 17

Prevents over inflation of the lungs
Stretch receptors in the lung link to the respiratory centre by the vagus nerve and inhibit respiration when lung volume reach max

Question 18

Describe the pupillary reflex

Answer 18

Used to assess brain trauma and deterioration of brain tissue
Elicited by shining a light into one eye whilst covering the other pupil should constrict
Normally pupils round and both equal size
Normal reaction brisk

Question 19

Describe the patella tendon reflex

Answer 19

Assesses the nerves between the region of the spinal cord between lumber 2 and 4
Elicited by sharply tapping just below the knee with the base of a Taylor hammer

Question 20

Describe the planter reflex

Answer 20

Superficial spinal reflex
Elicited by firmly drawing the handle of a Taylor hammer along the lateral border of the foot from the heel to big toe
In adults toes flex and move together
In babies toes flare and big toe move upwards babinski’s sign