Week 6

Question 1

• Discuss the structure, function and organisation of the spinal cord.

Answer 1

Vertebral canal, 1 mm in diameter, made of white matter and grey matter with flow of CSF
Has ascending tract-sensory, descending tract-motor
dorsal root-sensory afferent, ventral root motor efferent

Question 2

• Discuss the different types of white matter tracts.

Answer 2

Dorsal column-sensory-3 modalities
Ventral Column-motor and sensory-2 modalities sensory
Lateral column-motor and sensory 2 main sesnsory modalities

Question 3

• Describe the classification and ‘mechanisms’ of action of reflexes.

Answer 3

Involuntary almost instantaneous movement in response to stimulus through when sensroy information from sensory axon, upper motor neurons and colaterals of lower motor neurons are received by interneuron enabling a recirpocal inhibition, or contraction of a set muscle with relaxation of antagonist muscle

Question 4

• Briefly discuss reflex-tests.

Answer 4

A classic example of a stretch reflex is the patellar reflex.

Striking the patellar ligament just below the patella stretches the quadriceps muscle.
Sensory receptors in the muscle are stimulated and trigger an impulse in a sensory axon.
The sensory axon synapses directly with a motor neuron that conducts the impulse to the quadriceps, triggering contraction.
At the same time, an interneuron that supplies an α motor neuron of the antagonist hamstring muscles is stimulated with resulting inhibition of the hamstrings.

Question 5

• Describe the pyramidal motor pathway (corticospinal tract).

Answer 5

Cortical spinal tract is all about motor planning and initiation.
Cell bodies in upper motor neuron within the gray matter in the motor cortex=your motor areas and you pre-motor areas travel down to axons of those neuronal cell bodies that will head out to various regions of the brain into the spinal cord. Axons go through a
region of the white matter-the corona radiata, through the internal capsule, and it heads all the way down into the brainstem where pyramidal decussation occurs

Question 6

• Describe Somatosensation.

Answer 6

ability to perceive touch, temperature, pain and body position through action potentials

Question 7

Compare the 3 main sensory pathways:
• Dorsal Column-Medial Lemniscal (DCML).
• Anterior Spinothalamic.
• Lateral Spinothalamic.

Answer 7

DCML-proprioception
Anterior spinithalamic-crude touch
Lateral spinothalamic-thermal, mechanical, chemical-pain

Question 8

• Identify the divisions of the autonomic nervous system.

Answer 8

Parasympathetic-prepares body for physical activity-visceral organs, adrenal gland, sweat, vascular smooth muscle
Sympathetic-organs in head trunk neck, genitalia-rest and digest

Question 9

• Define the different types of sympathetic receptors, the tissues in which they are expressed and the effect of stimulation.

Answer 9

alpha receptors-1 and 2-smooth muscle contraction
beta receptors 1,2 and 3-smooth muscle relaxation, cardiac muscle contraction
muscarinic receptor-sweat

Question 10

• Define the different types of parasympathetic receptors, the tissues in which they are expressed and the effect of stimulation.

Answer 10

muscarinic-sweat

Question 11

• Briefly describe the visual pathway.

Answer 11

Light waves pass through cornea pass through pupil pass through lens which focuses light waves pass to retina to optic nerve to optic tract to thalamus at lateral geniculate nucleus to primary visual cortex

Question 12

• Briefly describe the auditory pathway.

Answer 12

bipolar cells in ganglion take info from hair cells to vestibulocochlear nerve which goes to cochlear nuclei in the medulla to lateral lemniscus to inferior colliculi to medial geniculate nuclei to primary auditory cortex

Question 13

• Briefly describe the process underlying speech.

Answer 13

information from auditory, sensory and proprioception parts of brain to cortex is processed from wernicke’s area to broca’s area to permotor and motor cortexes to corticobulbular tract to motor nuclei of cranial nerves to cranial nerves to muscles of tongue, pharynx, face and suprahyoid muscles and this goes to auditory sensory and proprioception parts of brain

Question 14

• Briefly describe gustatory and olfactory processes.

Answer 14

sensory information from taste buds innervated by 3 nerves-glossopharyngeal nerve, facial nerve, vagus nerve- goes to solitary nucleus in medulla through pons to thalamus ventral posterior nuclues to primary gustatory cortex

odorant molecule concentrated near olfactory cillia to olfactory receptor cells to olfactory nerve to olfactory bulb terminating at olfactory cortex

Question 15

• Describe the function of bones and the skeletal system.

Answer 15

protection, support, mineral storage, blood cell production, energy stroage

Question 16

• Classify bones according to their shape.

Answer 16

long bones-humerus
short bones-carpals
flat bones-sternum
sesamoid bones-patellae
irregular bones-vertebrae

Question 17

• Identify the structural components of a long bone.

Answer 17

Diaphysis = Shaft
• Made of Cortical (compact) bone
• Epiphysis = Ends of bone
• Contains Trabecular (spongy) bone
• Metaphysis = Between Epiphysis & Diaphysis
• Contains Trabecular (spongy) bone
• Medullary Cavity = Marrow cavity in diaphysis
• Articular Cartilage = Covers epiphyses
• Smooth frictionless movement at joint

Question 18

• Describe the histology of bone tissue.

Answer 18

• Bone is a Supportive Connective Tissue
• Cells: Osteoprogenitor, Osteoblasts, Osteocytes & Osteoclasts
• Extracellular matrix:
• Organic components = Collagen fibres
• Inorganic components = Mineral salts

Question 19

• INTRAMEMBRANOUS Discuss the processes of bone formation and growth/remodelling.

Answer 19

• Intramembranous Ossification =Bone forms in embryonic tissue membranes
• Mesenchymal stem cells cluster at an ossification centre in embryonic connective
tissue differentiation into the bone environment is initiated
• Mature Osteoblasts begin to produce bone at the ossification centre
Bone deposits grow outwards from ossification centre
• Trapped osteoblasts
• Osteoblasts on the surface (and osteocytes in lacunae) begin to promote calcification
• Calcification refers to the impregnation of inorganic materials (calcium & phosphates) into
the bone matrix
• Hardening the bone
Blood vessels grow into area to provide nutrients
• With new blood vessels comes the delivery of osteoclasts
• Osteoclastic resorption begins to form internal trabecular structure
• Continued bone remodelling forms typical bony product

Question 20

•ENDOCHONDRAL Discuss the processes of bone formation and growth/remodelling.

Answer 20

• Endochondral Ossification=Bone forms in embryonic hyaline cartilage
Forming Hyaline Cartilage Model
• Chondroblasts secrete cartilage matrix (form from MSCs)
• Trapped chondroblasts become chondrocytes in lacunae
• Chondrocytes divide (mitosis) inside lacunae
• New daughter cell secretes cartilage matrix from within
lacunae enlarging cartilage model
• Interstitial growth
• Cartilage also deposited on external surface by
chondroblasts
• Appositional growth
Ossification at edges of Bone
(formation of diaphysis
• Blood vessels grow around edge of cartilage
model
• Osteogenic cells within perichondrium
differentiate
• Osteoblasts
• Osteoblasts lay down superficial bone to form
edges of diaphysis
Formation of the Primary
Ossification Centre
• Blood vessel penetrates cartilage at diaphysis
• Osteoblasts enter alongside blood vessels to
produce spongy bone template within cartilage
model diaphysis
• Primary ossification centre
• Bone growth increases and spreads towards both
ends of cartilage model
Epiphyseal line formation and
interstitial growth
• Epiphysis remodelled to form trabecular (spongy)
bone
• Line between Epiphysis and Metaphysis remains
as cartilage
• Until puberty
• Cartilage (epiphyseal) plate grows to lengthen
the long bone
• Interstitial growth

Question 21

• Explain how a bone repairs itself after a fracture.

Answer 21

Step 1: Formation of blood clot
• A.K.A Hematoma
• Ruptured blood vessels due to fracture
• Local cells die from injury
• Macrophages transported in blood arrive and
clean (phagocytose) area
• Hours to Days
• In Normal Health = 8-12 weeks to repair
• Step 2: Formation of Fibrocartilaginous callus
• Once area clear of debris and hematoma cleared
• Fibroblasts & Chondroblasts deposit collagen fibres to
form a fibro-cartilage mould around fracture sight
• Known as the soft callus
• Days to Weeks
Step 3: Formation of Bony (hard) Callus
• Osteoblasts create spongy bone connecting bone ends
• 3-4months
• Step 4: Remodelling
• Osteoclasts/Osteoblasts smoothen bony callus
• Normal cortical and trabecular bone product
• years

Question 22

• Discuss the effect of exercise, nutrition, and hormones on bone tissue.

Answer 22

if not getting the right amount of minerals, the right amount of vitamins, change
the integrity of the actual bone material. Other insufficiencies may be hormones, different hormones like sex hormones, estrogen and testosterone. If we don’t have adequate amounts, that’s going to affect how the bone is grown and how the bone
is developed. • Loss of oestrogen in menopause slows down Osteoblast and increase osteoclast risk Post menopausal Osteoporosis

Question 23

• Discuss both the functional and structural classifications of body joints.

Answer 23

Structural Classification: Refers to what links the adjacent bones
• Bony Joint – complete fusion of two bones
• Fibrous Joint – held together by dense collagen fibres
• Cartilaginous Joint – held together by cartilage (hyaline or fibrocartilage)
• Synovial Joint – held together by a fibrous joint capsule & ligaments and contains a
joint space between bone ends
• Functional Classification: Refers to what links the range of motion at
and articulation
• Synarthrosis – Immobile, with no movement
• Amphiarthrosis – Partial, minor movements possible
• Diarthrosis – Freely mobile, wide range of movements possible

Question 24

• Describe the characteristic features of fibrous, cartilaginous, and synovial joints and give examples of each.

Answer 24

• Bony Joint – complete fusion of two
bones-metopic suture
• Fibrous Joint – held together by dense
collagen fibres-syndesmosis in ankle
• Cartilaginous Joint – held together by
cartilage (hyaline or fibrocartilage)-intervertebral disc
• Synovial Joint – held together by a
fibrous joint capsule & ligaments and
contains a joint space between bone
ends-knees

Question 25

• Discuss the structure of specific body joints and the movements they allow.

Answer 25

Gliding Joint
• Allow for small, gliding or sliding movements between two or more bones
• Adjust to accommodate to an external surface architecture like tightly holding a
rope
• Planes of Movement =. Nonaxial
B) Hinge Joint
• Allows for significant flexion and extension motions
• like opening and closing a door
• Planes of Movement = . Uniaxial
C) Pivot Joint
• Allows for significant rotating motions
• Planes of Movement = One (Vertical plane); i.e. Uniaxial
D) Condylar Joint
• Permits several movements like spreading your fingers apart or making a fist
• Planes of Movement = Two (Sagittal & Coronal Plane); i.e. Biaxial
E) Saddle Joint
• Permits several movements like giving a “thumbs up” or touching your “pinky finger”
with your thumb
• Planes of Movement = Two (Sagittal & Coronal Plane); i.e. Biaxial
F) Ball & Socket Joint
• Permits the most movements possible like moving your arm around & around at the
shoulder
• Planes of Movement = Three (Sagittal, Coronal & Vertical Plane); i.e. Mutliaxial

Question 26

• Outline the general role of muscles in the body.

Answer 26

1. Motion: Walking, running, blood & urine (peristalsis), air (external respiration)
2. Stabilising Body Position: Posture and alignment of the skeleton
3. Regulation of Organ Volumes: Smooth muscles and sphincters
4. Support of Soft Tissue: Protect and maintain position of organs (Pelvic)
5. Maintain body temperature: Production of heat through contractions/shivering
6. Storage nutrients: Amino acids (protein) and glycogen

Question 27

• Define the different types of muscle tissue.

Answer 27

1. Skeletal Muscle: Attaches to bone
2. Cardiac Muscle: Forms the heart
3. Smooth Muscle: Located within walls of hollow organs / blood vessels

Question 28

• Explain the organisation of muscle tissues (cardiac and smooth).

Answer 28

Cardiac
Striated, short, branched, muscle cells
Single centrally located nucleus
Individual cells connected by intercalated discs

Smooth
Visceral ‘Single-unit’ Smooth Muscle Tissue
Multiple smooth muscles to form one muscle unit
Gap junctions allow unison contraction

Multiunit Smooth Muscle Tissue
Individual, independent smooth muscle cells have
their own nerve ending
Contract independently

Question 29

• Describe how muscles contract and relax.

Answer 29

Neurotransmitters: Acytcholine release from axon
terminal and receptors on the sarcolemma
Calcium release: Action potential stimulates
the release of Ca from sarcoplasmic reticulum
Calcium-binding: Binds to troponin exposing
active sites on thin filaments beginning the
contraction cycle
Calcium-binding: Binds to troponin exposing active sites on thin filaments
Actin – Myosin: Myosin head binds to exposed Actin thin filament
Power Stroke: Myosin head pivots, pulling the thin filament towards to M-line and
shortening the muscle
ATP: Binds to Myosin head after the ‘power stroke’ releasing it from actin in
preparation for the next cycle
Neurotransmitters: Ach broken down, ending
action potential generation
Calcium reabsorbed: concentration
decreases in cytosol > tropomyosin covers thin
filament
Contraction end: Cross bridges detach and
muscle returns to resting length

Question 30

• Describe the structure and function of skeletal muscle tissue.

Answer 30

Voluntary Control
Innervated by the Somatic Nervous System
(Part of the Peripheral Nervous System)

1. Each muscle cell is covered by a thin areolar
   connective tissue: Endomysium
2. Many muscle cells (muscle fibres & motor units)
   bundle together to form a Fascicle
3. Each Fascicle is covered by a fibrous connective
   tissue: Perimysium
4. Many fascicles bundle together to form the muscle
5. The entire muscle is covered by fibrous connective
   tissue: Epimysium
6. The epimysium is connected to the deep fascia
   (dense CT) & attaches to Tendons

Question 31

• Explain how muscles work with tendons to move the body.

Answer 31

Tendons are long, whitish strap-like bands that transmits
contractile force from muscle(s) to the location on bone
• Increasing mechanical strength and efficiency
• Tendons are a type of dense regular connective tissue

Question 32

• Explain the development and regeneration of muscle tissue.

Answer 32

Cardiac Muscle:
Cannot divide or regenerate if injured (Ischemia); healing via fibrosis
Hypertrophy through cardiomyocyte enlargement from exercise, pathology
(cardiomegaly), hypertension or valvular disease.

Smooth Muscle:
Regeneration is possible
Cells can grow in size (hypertrophy) or number (hyperplasia)
• Uterus thickening during luteal phase of menstrual cycle
• Visceromegaly: Pathology or HGH supplementation

Question 33

• Explain the criteria used to name skeletal muscles.