3 Label the diagrams A – dendrite B – nucleus C – myelin sheath D – axon E – Schwann cellF – side or colateral branch of axonG – node of RanvierH - motor end plate/axon terminalI - neurilemmaLabel the diagramsA – motor neuronB – connector neuronC – sensory neuron1 – cell body of the sensory neuron2 – synapse3 – cell body of connector neuron4 – synapse5 – axon of motor neuron6 dendrite of motor neuron7 – muscle fibre8 – motor end plate9 – dendrite of sensory neuron10 – receptor cell
5 Functions of the skeleton The skeleton has a number of functions:supportmovementprotectionstorageblood cell manufacture
6 EXTERNAL STRUCTURE OF A LONG BONE PROXIMAL EPIPHYSISDIAPHYSIS (SHAFT)DISTAL EPIPHYSISCONDOYLE
7 Internal structure of a bone 1 = articular cartilage2 = spongy or cancellous bone3 = compact bone4 = periosteum5 = nutrient artery6 = diaphysis or shaft7 = Haversian system
8 Functions of bone structures 1. allows smooth movement at the joint2. filled with red marrow. Red marrow is important for manufacture of red cells, and storage of minerals3. strength and support4. is responsible for laying down bone on its inner surface (the outer surface of the shaft), to allow bone growth and repair, as well as providing a surface for the attachment of tendonsEndosteum is responsible for laying down bone on its outer surface (the inner surface of the shaft), to allow bone growth and repair5. provide nutrients and oxygen for the bone.Yellow marrow (fat) fills the cavity of the shaft
9 This is the type of tissue that makes up articular cartilage This is the type of tissue that makes up articular cartilage. Cartilage has relatively few cells and lots of matrix to make it strong and slightly elastic
10 This is compact bone seen from above You can see several haversian systems side by side Compact bone has quite a few cells but also lots of rocky matrix to make it strong
11 Spongy Bone Reddish colour, Softer than compact bone because there are more spaces in spongy boneThis is where the red marrow isBlood cells are made in the red marrow of bonesProvides support for the skeleton without the heavy weight of compact bone
12 Compact bone shiny, bluish colour hard but still slightly elastic Articular cartilageshiny, bluish colourhard but still slightly elasticIs for protection of end of boneIs for shock absorptionLoss of articular cartilage is called osteoarthritis.has a poor blood supplyCompact bonewhite coloured tissuehard, bony/rockyIs for supportis made of columnar shaped structures called haversian systemshas a good blood supply
13 Microscopic structure of bone Describe the main features and roles of the following in bone:Matrix – non-cellular material, secreted by osteocytes – consists of protein with large amounts of inorganic salts (eg calcium and phosphotes)Haversian system – or osteons – are units of organisation found in compact bone. These run parallel to the length of the bone and provide strength.Osteocytes – bone cells – these make the matrix and are found within the lacunae – small spaces in the matrixLamellae – concentric layers of matrixCanaliculae – tiny canals running between lacunae, containing projections from osteocytesTrabeculae – irregular arrangements of bony plates found in spongy bones. Osteocytes are found within the spaces of these plates
14 Microscopic structure of cartilage Describe the main features and roles of the following in cartilage:Chondrin – protein-carbohydrate matrixFibres – protein called collagen that are embedded in the chondrinChondroblasts – cells that secrete matrixChondrocytes – mature chondroblasts, fully surrounded by matrixLacunae – small spaces containg the chondroblasts/chondrocytesPerichondrium – fibrous layer covering cartilage. This contains blood vessels which supply the cartilage with nutrients
15 Types of cartilage Describe the main characteristics of Hyaline cartilage – many tightly packed very fine collagenous fibres. This gives great strength and flexibility. Examples include articular cartilage and the rings of bronchi and tracheaElastic cartilage – contains elastic fibres as well as collagen fibres, which are not so tightly packed. An example is the outer earFibro-cartilage – has parallel bundles of thick collagenous fibres which are less compacted than hyaline cartilage and so can be compressed slightly. Examples include intervertebral discs, articular cartilage of the knee and tissue joining the 2 sides of the pelvis
16 JointsA joint is a point of the skeleton at which two or more bones meet.A joint allows the skeleton to move (or articulate) at that point.Joints are points where the bones growThere are three kinds of joints in the human skeleton1. Fixed or fibrous joints2. Slightly movable (Cartilaginous) joints3. Freely movable (Synovial) joints
17 Fixed (Fibrous) joints allow no movement Fixed (Fibrous) joints allow no movement. They do allow the bone to flex or give under pressure. They are found between the bones of the skull When the baby is born some of these joints are open…the fontanelle
18 Slightly movable or Cartilaginous joints allow a little movement Slightly movable or Cartilaginous joints allow a little movement. Examples of cartilaginous joints include the pubis symphysis and intervertebral discs
19 Freely movable or Synovial joints allow a wide range of movements Freely movable or Synovial joints allow a wide range of movements. An example of a Synovial joint is the hip joint
20 There are six types of Synovial Joints 1. Ball and socket joint…eg hip, shoulder2. Hinge joint…eg elbow, knee3. Pivot joint…eg atlas – axis joint4. Gliding joint…eg between two vertebrae5. Saddle joint…eg thumb joint6. Condyloid joint …eg wrist bones – radius & ulna
21 1. The Ball and Socket joint Consists of a round head at the end of one bone that fits into a cup – shaped depression in the other bone called a socketCan move in three dimensionsup and downforward and backwardsround and round (circumduction)Examples are hip and shoulder
22 2. The Hinge jointConsists one upper bone meeting two lower bones.Hinge joints can open (extension) and close (flex)
23 Pivot jointPivot joints come in several different shapes. The easiest to visualise is the Atlas – Axis joint in the spinePivot joints allow rotational movement onlyAnother example of a pivot joint is the radius – ulna that allows us to rotate our wrist
24 Gliding jointExamples include the wrist and the vertebral processesGliding joints can flex, extend and rotate
25 Saddle jointThe thumb is a saddle jointThumbs can move in three directions; flex, extend rotate
26 6. Condyloid jointCondyloid joints can flex, extend and manage a little rotationExamples include the joints between finger bones
28 Synovial joints Describe the functions of the following structures: Synovial capsule surrounds the joint and helps stabilise it and hold it all togetherSynovial membrane is thin and smooth, to reduce friction, and secretes synovial fluidSynovial fluid is thick and sticky, and acts as a lubricant for the jointArticular cartilage provides a smooth surface to reduce friction as the bones move across each otherArticular disc are cartilaginous discs which act as shock absorbersBursae are fluid filled sacs which act as shock absorbersAccessory ligaments join the bones and keep them togetherThree factors keeping articular surfaces in contact areThe fit of the articulating bonesThe strength of the joint ligamentsTension provided by muscles around the joint
31 Movements possible at synovial joints Flexion is the bending of a jointExtension is the straightening of a jointAbduction is movement of a joint away from the bodyAdduction is movement of a joint towards the bodyRotation is movement of a bone around its long axisCircumduction is circular movementPronation is rotation of the hand so the palm faces backwardsSupination is rotation of the hand so the palm faces forwards
32 Sample multiple choice Which part of the structure shown above increases the speed of nerve impulse transmission?(a) A(b) B(c) C(d) DWhich one of the following statements about the neuron shown above is correct?(a) This neuron does not show evidence of a Schwann cell.(b) Structure B will produce the myelin sheath.(c) Structure D receives impulses from other neurons.(d) Structure A transmits impulses to the cell body.
33 Sample multiple choice Which part of the structure shown above increases the speed of nerve impulse transmission?(a) A(b) B(c) C(d) DWhich one of the following statements about the neuron shown above is correct?(a) This neuron does not show evidence of a Schwann cell.(b) Structure B will produce the myelin sheath.(c) Structure D receives impulses from other neurons.(d) Structure A transmits impulses to the cell body.
34 Practice exam question Patients who are admitted to hospital due to damage to their cerebrum experience a loss of function in many parts of their body and yet a number of bodily functions (eg heart beat) continue to work normally.a) Describe the symptoms that you might expect to see in a patient with cerebral damage and relate these to the functions of the cerebrum.b) Give an explanation for how the body is able to still survive in the absence of a fully functioning cerebrum.
35 Practice exam question Patients who are admitted to hospital due to damage to their cerebrum experience a loss of function in many parts of their body and yet a number of bodily functions (eg heart beat) continue to work normally.a) Describe the symptoms that you might expect to see in a patient with cerebral damage and relate these to the functions of the cerebrum.Sensory areas in the cerebral cortex interpret impulses from receptorsMotor areas in the cerebral cortex control muscle movementsAssociation areas in the cerebral cortex are concerned with intellectual and emotional processes (eg thinking, memory, etc)Certain areas in the cerebrum are also associated with particular task eg reading, writing, speech, etcTherefore we would expect the symptoms would vary according to the area damaged – but may include impairment of the senses, loss of ability to control movement or difficulty with some tasks eg reading, writing or talking or loss of memory or problem solving abilitiesb) Give an explanation for how the body is able to still survive in the absence of a fully functioning cerebrum.Lower centres of the brain eg the hypothalamus and medulla are responsible for control of autonomic functions such as breathing, heart rate, blood pressure, secretion of digestive juices, movement of alimentary canal,,body temperature, sympathetic and parasympathetic responses eg diameter of eye, vasodilation and vasoconstrictionSo long as they are undamaged the body can still survive.