Musculoskeletal System Flashcards
What are the four types of primary tissue?
Epithelial Tissue
Connective Tissue
Nervous Tissue
Muscle
Where are epithelial tissues found?
Body coverings (outside) Body linings (outside) Glandular tissue (tubes)
What are the functions of epithelial tissues?
Protection
Absorption
Filtration
Secretion
How are epithelia classified (according to two features) and what are the names and features of these different classifications (5 in total)?
Classified according to:
Number of cell layers
Shape of cells
Different categories:
Simple - one layer of cells
Stratified - more than one layer of cells
Squamous - flattened
Cuboidal - cube-shaped ('square')
Columnar - column-like (tall rectangle)
How many layers of cells do simple epithelia have?
One layer
How many layers of cells do stratified epithelia have?
more than one layer
What shape are squamous epithelia?
Flattened
What shape are cuboidal epithelia?
Cube-shaped (‘square’)
What shape are columnar epithelia?
Column-like (tall rectangle)
Which type of cells have a single layer of flat cells with flat nuclei
Simple Squamous epithelium
Which type of cells are often involved in diffusion of substances across the barrier they form?
Simple Squamous epithelium
Give two examples of simple squamous epithelium
Endothelium - epithelial cells lining the blood and lymph vessels
Mesothelium - lining of the body cavities
Which cells are a single layer of cube like cells?
Simple cuboidal epithelium
Which cells are common in glands and their ducts?
Simple cuboidal epithelium
Which cells are often polarised?
Simple cuboidal epithelium
Which cells are important for absorption and secretion?
Simple cuboidal epithelium
Which cells form walls of kidney tubules?
Simple cuboidal epithelium
Which cells form a single layer of tall cells?
Simple columnar epithelium
Which cells are a variety of heights depending on the function of the cell?
Simple columnar epithelium
In which cells would you normally see nuclei on the basal part of the cell?
Simple columnar epithelium
Goblet cells are what type of epithelial cell, and where are they found?
Simple columnar epithelium, found in the lining of the digestive tract
What is psuedostriated epithelium?
Single layer of epithelial cells but some are shorter than others, meaning it often looks like a double cell layer
What cell type is he most common epithelium?
Stratified Squamous Epithelium
What type of epithelium can be keratinised or non-keratinised?
Stratified Squamous Epithelium
Give two examples of Stratified Squamous Epithelium
Skin
Oesophagus
What are the functions of connective tissue?
Binds body tissues together
Supports the body framework
Wound repair/ inflammatory response
What makes up connective tissue?
Cells (free and fixed)
Fibres and extracellular matrix
What are the two main classes of connective tissue?
Loose connective tissue
Dense connective tissue
What are the subgroup within dense connective tissue?
Dense regular connective tissue eg tendons and ligaments
Dense irregular connective tissue eg skin
What are some examples of dense irregular connective tissue?
Skin
What are some examples of dense regular connective tissue?
Tendons and ligaments
What is the function of dense regular connective tissue?
Resistance to traction forces
What is the function of dense irregular connective tissue?
Mechanical support
What is the most common form of connective tissue?
Loose connective tissue
Which type of connective tissue contains all fibre types?
Loose connective tissue
Which type of connective tissue can retain excess fluid?
Loose connective tissue
Which type of connective tissue is NOT resistant to stress?
Loose connective tissue
Which type of connective tissue provides structural support of the epithelia of the major organs?
Loose connective tissue
What is the most common native cell type of connective tissue?
Fibroblasts
What are the role of fibroblasts?
Synthesise collagen and components of the ECM
How are the structure of fibroblasts related to their function?
Elongated nuclei
Small amount of cytoplasm
Spindle/ elongated shape
What is the extracellular matrix?
Proteoglycans that occupies the space between cellular and fibrillary elements of the connective tissue.
What is the role of the extracellular matrix?
Determine permeability of the connective tissue layer to solutes and proteins
Which type of cartilage is the most common, with a ‘glassy’ appearance?
Hyaline cartilage
What is hyaline cartilage composed of?
Chondrocytes
Collagen fibres (type II)
Extracellular matrix
In adults, where is hyaline cartilage found?
Nose, larynx, knee joints
What is the difference in structure between hyaline and elastic cartilage?
The ECM in elastic cartilage contains more elastin fibres
Give two example of where you would find elastic cartilage
External part of the ear
Some parts of the larynx
Which type of cartilage is opaque in appearance and contains low amounts of proteoglycans?
Fibrocartilage
Where is fibrocartilage found?
The discs between the vertebrae
What sort of tissue is loose and contains adipocytes?
Adipose tissue
What are the functions of adipose tissue?
Insulation
Energy storage (fats)
Protection
True or false - diffusion through a membrane increases with a high concentration gradient?
True
Does diffusion through a membrane increase with a high or low molecular weight?
Low molecular weight
Does diffusion through a membrane increase with a high or low lipid solubility?
High lipid solubility
True or false - diffusion through a membrane increases with a high degree of ionisation
False - diffusion through a membrane increases with a low degree of ionisation
What are aquaporins?
Transmembrane proteins with a narrow hour glass shape and charged walls, allowing only H2O through.
How is the body’s fluid distributed (solid vs fluid)
1/3 solid - 2/3 fluid
How is the body’s fluid distributed intracellularly vs extracellularly?
1/3 extracellular - 2/3 intracellular
15L : 30L
How is the body’s extracellular fluid distributed invtravacular vs intersitial?
1/3 intravascular - 2/3 intersitial
10L : 5L
What are the differences in Na+ concentration between interstitial:plasma:intracellular?
140:140:10
What are the differences in K+ concentration between interstitial:plasma:intracellular?
4:4:140
What are the differences in Ca2+ concentration between interstitial:plasma:intracellular?
2:2:0
What are the differences in Mg2+ concentration between interstitial:plasma:intracellular?
1.5:1.5:2.5
What are the differences in Cl- concentration between interstitial:plasma:intracellular?
100:100:4
What are the differences in HCO3- concentration between interstitial:plasma:intracellular?
25:25:15
What are the differences in HPO42- concentration between interstitial:plasma:intracellular?
2:2:100
What are the differences in protein concentration between interstitial:plasma:intracellular?
0:1.2:2.6
Which body compartments is water able to move between?
All of them, speed greatly enhanced by aquaporins
How does glucose move between body compartments?
Passes through endothelium easily and readily into most cells via glucose transporters
How do electrolytes move between body compartments?
They pass through endothelium easily but not cell membranes (except via specific mechanisms)
How do proteins move between body compartments?
Minimal movement between compartments - transfer by pinocytosis when needed
What is pinocytosis?
Transfer from extra to intracellular fluid, via invaginated membrane which forms vesicle around particle.
Eg Immunoglobulin transfer across placenta
What is endocrine signalling?
Hormone secretion into blood by endocrine gland.
Used for slow long range signalling
Examples: Testosterone and insulin
What is paracrine signalling?
Short range signalling involving release of chemical messenger from secretory cell to adjacent target cells
Examples: Cytokines released from immune cells.
VEGF and NO release
What are the four types of cell signalling classes?
Endocrine signalling
Paracrine signalling
Direct contact
Synaptic signalling
What type of signalling molecule is adrenaline?
Small molecule
What type of signalling molecule is hCG?
Peptide/ protein
What type of signalling molecule is LH?
Peptide/ protein
What type of signalling molecule is Insulin?
Peptide/ protein
What type of signalling molecule is Testosterone?
Steroid
What are the 4 main types of cellular receptor?
Steroid receptor
G protein coupled receptor
Ligand gated ion channels
Enzyme linked
Whats the ratio of Na+:k+ exchanged in the ATPase pump?
3 Na+ out
2 K+ in
What are the three types of muscle tissue
Skeletal
Cardiac
Smooth
What are the properties and location of skeletal muscle?
Voluntary or striated muscle, it is the muscle attached to bones
What are the properties and location of cardiac muscle?
Striated muscle, found in the walls of the heart
What are the properties and location of smooth muscle?
Involuntary or visceral muscle, found in the walls of hollow organs - blood vessels, GIT, uterus etc.
In terms of the development of the musculoskeletal system, what do dermatomes give rise to?
Gives rise to the connective tissues and dermis of the skin
In terms of the development of the musculoskeletal system, what do myotomes give rise to?
Give rise to the skeletal muscles (dorsal and ventrolateral muscle of the body wall & migrate into limb buds).
In terms of the development of the musculoskeletal system, what do sclerotomes give rise to?
Give rise to vertebrae
In embryology, where are smooth muscles derived from?
Lateral plate mesoderm and neural crest cells
In embryology, where are cardiac muscles derived from?
Splanchnic (visceral) layer of lateral plate mesoderm surrounding developing heart tube
What branch of the nervous system are the spinal nerves part of?
Somatic nervous system
How many pairs of spinal nerves are there?
31 pairs of spinal nerves
What is a myotome?
Group of muscles innervated by spinal nerves derived from the same segmental level of the spinal cord as the somite
What is a motor unit?
Groups of muscle fibres and single motor neuron that supplies them
What dictates the size of the motor unit?
Which muscle is involved and what sort of movement it has to produce eg gross or fine motor movement
What is the generic structure of a muscle fibre?
Fascicle –> muscle fibre –> myofibril –> sarcomere
Define tendon
Thick band/ cord of dense connective tissue attaches muscle to bone
Define aponeurosis
Broad sheet of dense connective tissue with which muscle attaches to bone
Define muscle attachment site origin
Attachment site of muscle tendon/ aponeurosis to less moveable or stationary bone
Define muscle attachment site insertion
Attachment site of muscle tendon/ aponeurosis to more moveable bone
Give some symptoms of compartment syndrome (6 Ps)
Pain out of proportion
Palpably tense compartment
Pain with passive stretch
Parathesia/ hypothesia
Paralysis
Pallor
What is a synergistic contraction?
Synergistic muscles contract to prevent unwanted movements or aid the action of the agonist.
When would you see a winged scapula?
Paralysis of the serratus anterior muscle due to damage of the long thoracic nerve
What is neuromuscular disease?
Occurs due to disease or damage of somatic motor neuron, neuromuscular junctions or muscle fibres
What is Myasthenia Gravis?
Autoimmune damage to NMJ (nicotinic ACh receptors blocked or destroyed).
Leads to muscle weakness and fatigue
What is Duchenne’s r Becker’s muscular dystrophy?
X-linked inherited skeletal muscle fibre degenerative disease.
Causes muscle weakness and wasting, affects mainly boys.
What is muscle hypertrophy?
Skeletal muscle growth after birth.
Occurs through enlargement of existing muscle cells.
Influenced by hormones and exercise.
What is disuse atrophy?
Inactivity for extended period of time causes loss of protein mass leading to decreased muscle size.
My be due to paralysis or prolonged bed rest
What is sarcopenia?
Reduction in muscle mass due to ageing.
What factors influence sarcopenia?
Influenced by reduced hormonal signalling (IGF, insulin, testosterone), reduced nervous stimulation, muscle disuse, protein synthesis and poor diet.
Where is calcium normally distributed within the body and in what proportions?
99% in skeleton & teeth
- 9% is intracellular
- 1% in the ECF
What form is calcium found as in bones?
Hydroxyapetite crystals Ca3(PO4)2
What is the role of calcium within bones?
Provides structural strength to bones - makes them hard
What is the role of calcium within the nervous system?
Release of neurotransmitters from pre synaptic neurons and the NMJ is triggered by calcium entry from the ECF
What is the role of calcium within muscle contraction?
Entry of Ca2+ into cardiac and smooth muscle cells from the ECF is a key step in excitation contraction coupling
What is the role of calcium within the endocrine system?
Movement of extracellular Ca2+ into endocrine cells triggers hormone release.
eg Ca2+ influx causes membrane depolarisation which causes pancreatic islet cells to release insulin
What is the role of calcium within the blood?
Calcium is a cofactor in several steps within the clotting cascade
What is the role of calcium within intracellular processes?
Calcium functions as a second messenger in cell signalling pathways and as a cofactor for enzyme function in chemical reactions
What three hormones control levels of ionized calcium (Ca2+) in the plasma?
Parathyroid hormone (PTH)
Vitamin D
Calcitonin
Where is parathyroid hormone released from?
Parathyroid gland (found on the posterior side of the thyroid)
What is parathyroid hormone released in response to?
Decreasing plasma Ca2+ concentration (fast acting response)
Where is vitamin D synthesised and then converted into its active form?
Synthesised and released by keratinocytes in the skin.
Undergoes chemical modification in the kidney and liver to give the active form - calcitriol
What is the active form of vitamin D?
Calcitriol
What is vitamin D activated in response to?
Decreasing plasma Ca2+ concentration (slow acting response)
Where is calcitonin released from?
Cells of the thyroid gland
What is calcitonin released in response to?
Extreme increase in plasma Ca2+ concentration (hypercalacemia)
What are the symptoms of hypercalcaemia?
Loss of appetite Nausea and vomiting Constipation Fatigue, weakness and muscle pain Depression Headaches
What are potential ways in which you can develop hypercalcaemia?
Overactivity of the parathyroid gland (release of too much PTH)
Cancer
Too many calcium or vitamin D supplements
What to osteoblasts release in order to trigger osteoclasts to demineralise bone?
Rank L
What type of cells release Rank L and what is Rank L’s function?
Released by osteoblasts in order to trigger osteoclasts to demineralise bone.
What are the symptoms of hypocalcaemia?
Muscle seizures, cramps or spasms
Seizures
Numbness/ tingling in hands, feet and lips
Slow heart beat
What are the potential causes of hypocalcaemia?
Hypoparathyroidism
Chronic kidney disease
Hyperventilation
What do dermatome progenitor cells give rise to?
Connective tissue and dermis of the skin
What do myotome progenitor cells give rise to?
Skeletal muscle
What do sclerotome progenitor cells give rise to?
Bones
Where is smooth muscle derived from?
The lateral plate mesoderm and neural crest cells
Where is cardiac muscle derived from?
From the splanchnic layer of the lateral plate mesoderm surrounding the developing heart tube
Where is skeletal muscle derived from?
Derived from each myotome and receive their nerve supply from the spinal nerves derived from the same segmental level of the spinal cord as the somite
What is calcium homeostasis?
It is the rapid control of calcium plasma concentration by exchange between bone and extracellular fluid
What is calcium balance?
It is the longer control of total calcium ion stores by balancing calcium ion intestinal absorption and calcium ion urinary excretion
What is the normal range for plasma calcium ion concentration?
2-2.6 mmol/L
What influences calcium absorption?
Irons intake
Sunlight
Vitamin C
Exercise
What is the active version of vitamin D known as?
Calcitriol
What are the three main hormones involved in calcium homeostasis called?
Parathyroid hormone
Calcitonin
Calcitriol (vit D)
Where is calcium found?
50% dissolved in blood as Ca2+
40% bound to albumin
10% is bound to complex ions
99% of calcium in bone is in the form of calcium apatite
What is calcium used for in the human body?
Hormone release Maintenance of cell tight junctions Muscle contraction Neurotransmitter release Wound healing Intracellular signalling Enzyme activation Blood clotting
What does parathyroid hormone do?
It increases plasma calcium ion concentration
How does parathyroid hormone work?
A decrease in calcium ion concentration causes the increased production and release of PTH.
This causes an increase in osteoclast function (more bone is broken down) without
demineralising the bone, increasing calcium ion concentration.
This also causes an increase of calcium ion reabsorption at the kidneys in the PCT.
What is the role of vitamin D?
It increases plasma calcium ion concentration.
How does vitamin D work to maintain calcium homeostasis?
An increase causes:
Increase in bone demineralisation, increasing calcium ion plasma concentration.
Increase in kidney phosphate ion and calcium ion reabsorption.
Increase in intestinal calcium reabsorption and phosphate ion absorption.
What does calcitonin do?
It decreases plasma calcium ion concentration
How does calcitonin work to maintain calcium homeostasis?
Causes:
An increase of calcium ion deposition at the bones.
An increase of phosphate ion reabsorption and a decrease of calcium ion reabsorption/increase
calcium ion excretion.
What are the characteristics of connective tissue?
They are made up of widely separated cells
What are some examples of connective tissue?
Bone Blood Lymph Loose connective tissue Dense connective tissue
What is connective tissue made up of?
Ground substance which is involved in support, diffusion and stores water and
glycoaminoglycans.
Fibres.
What are the fibres in connective tissues and what are the
functions of these fibres?
Collagen: provides flexibility and strength.
Elastic fibres: provide stretch and recoil.
Reticular fibres: provide strength (they are collagen fibres
coated with glycoproteins).
What are some examples of dense connective tissues?
Dense regular
Dense irregular
Elastic connective
What are some examples of loose connective tissues?
Areolar
Adipose
Reticular
Why is cartilage a connective tissue?
It has widely specialised cells (chondrocytes)
It has a ground substance and fibres
What makes up the ground substance of cartilage and what fibres are in cartilage?
They are made up of:
Ground substance - chondroitin sulphate which provides
resilience.
Fibres - collagen which provides strength.
What is hyaline cartilage made up of, where is it located and
what is its function?
It is made up of fine collagen fibres.
It is located at the smooth surface of joints for movement.
It is for movement as it hyaline cartilage provides flexibility
and support.
What is fibrocartilage made up of and what property does it
give?
It is made up of thick collagen bundles.
It provides strength.
What is elastic cartilage made up of, what properties does it
give and what is its function?
It is made up of elastic fibres in a threadlike network.
It provides strength and elasticity.
Its function is that it maintains shape of structures.
How is bone considered a connective tissue?
It is because:
It has widely spaced cells.
It has a ground substance (water and mineral salts).
It has fibres (collagen fibres).
What property do collagen fibres provide to bone?
Flexibility so bone does not fracture easily.
What property do mineral salts provide to bone?
Hardness
What makes up the axial skeleton?
The bones of the head, neck and trunk
What makes up the appendicular skeleton?
They are the bones of the:
Limbs.
Pectoral girdle.
Pelvic girdle.
What are the different types of bones?
They are:
Long bones like the humerus and metatarsals.
Flat bones like the sternum.
Irregular bones like the pelvic bones.
Short bones like the carpal bones.
Sutural bones like the skull.
Sesamoid bones like the patella.
What are the functions of bones?
Structural support.
Protection of organs.
Assistance in movement.
Mineral homeostasis.
Blood cell production from red bone marrow.
Triglyceride (energy) storage from yellow bone marrow (adipose tissue).
How is the structure of cortical bone specialised for its function?
Cortical bone has multiple layers of collagen fibres that run in opposite directions. This prevents cracks spreading through bone and resists twisting forces.
What are the properties of trabecular (spongy) bone?
It is lightweight.
It is arranged along lines of stress to combat breakage as it absorbs compressive
loads.
Supports red and yellow bone marrow inside bones.
Where does bone marrow fill?
It fills the spaces of spongy bone and medullary cavity of the long bone.
What does red bone marrow consist of
and what is its function?
Red BM consists of haemopoetic tissue and is the site of red blood cell
production.
What does yellow bone marrow consist
of and what is its function?
Yellow BM consists of fat or adipose tissue and is able to revert to red BM after
severe blood loss to produce more red blood cells.
What is the function of osteoblasts?
Lay down new bone
What is the appearance of osteoblasts?
Uninucleated
How do they create an osteoid (bone
tissue)?
They create it by doing the following:
They secrete collagen.
The osteoblasts are then mineralised with calcium and other minerals.
They crystallise on the bones, strengthening the bones.
What are osteocytes?
They are bone cells trapped deep in the bone matrix.
How do osteocytes form from
osteoblasts?
They change their character to become osteocytes.
How do osteocytes communicate with
each other?
Via fine processes which run through canaliculi.
What are the functions of osteocytes?
The functions are:
Direct mineralisation.
Signal to osteoclasts to start repairing damage to the bone tissue.
They are involved in the release of calcium and phosphates into the blood to
maintain homeostasis.
What are osteoclasts?
They are very large bone cells which are formed within the marrow of the bone.
What do osteoclasts look like?
They are uninucleated.
What are the functions of osteoclasts?
They break down tissue secreting enzymes and acids.
For example:
HCl to dissolve minerals.
-Proteases to break down collagen.
Cathepsin K which degrades organic matrix components.
Involved in regulating mineral ions in the blood stream.
Essential for normal bone development, bone growth and healing.
What does bone remodelling do?
repairs breaks and microfractures from stresses.
What are the embryonic origins of osteoclasts
and osteoblasts?
Osteoclasts - haematopoietic stem cells from osteoclasts.
Osteoblasts - osteoprogenitor stem cells from the mesenchyme.
What is interstitial/endogenous bone growth?
Interstitial/endogenous bone growth involves an increase in the number of
cells and increase in matrix material.
What is a positional/exogenous bone growth?
Positional/exogenous bone growth involves no increases in the number of
cells but an increase in matrix material.
How does cartilage grow?
In length: endogenous and exogenous growth.
In thickness: endogenous and exogenous growth.
How does bone grow?
In length: endogenous growth.
In thickness: exogenous growth.
What blood vessels are found in bones?
Epiphyseal vessels.
Metaphyseal vessels.
Periosteal vessels.
Nutrient foramen and vessels.
When does ossification (bone formation)
occur?
It occurs in:
Embryo and foetus development.
Bone Growth in infancy, childhood and adolescence.
Remodelling of the bone.
Repair of fractures.
What occurs in initial bone formation in
embryo and foetal development?
Mesenchyme develops from the mesoderm (type of embryonic germ layer).
Cartilage and ossification (from the mesenchyme) in the 6th weeks causes the
formation of the general shape of bones.
What are the types of ossification (bone
formation)?
Endochondral and intramembranous ossification.
What occurs in intramembranous
ossification?
Bone forms on or within loose fibrous connective tissue membranes.
What is endochondral
ossification?
It is when bone forms from a cartilage template (for example this is how long bones are
formed).
Where does bone growth leading to increased bone length occur?
At the epiphyseal plate
When does increasing bone length occur and why?
Age 18-25 due to the epiphyseal plate closing.
Where does bone growth leading to increased bone thickness occur?
At the bone surface
What does bone remodelling involve?
Bone resorption by osteoclast cells.
Bone deposition by osteoblast cells.
What does mechanical stress induce
on bone structure?
Increased deposition of bone mineral salts and production of collagen fibres to increase
tensile strength of the bone.
Increase production of calcitonin which inhibits bone resorption and promotes bone
formation.
What does an absence of mechanical
stress lead to?
Abnormal bone remodelling because bone resorption outstrips bone formation.
Bone weakness due to demineralisation and decreased collagen fibre production.
How is a bone fracture
repaired?
Reactive phase:
- Blood vessels at the fracture line are broken.
- This forms a blood clot called a fracture haematoma.
- Bone cells die, causing swelling and inflammation.
- Phagocytes and osteoclasts remove dead or damaged tissue around the fracture haematoma.
Reparative phase - fibrocartilaginous callus forms:
- Blood vessels grow into the fracture haemotoma.
- Phagocytes clean up dead bone cells.
- Fibroblasts produce collagen and chondroblasts produce fibrocartilage.
- This forms the fibrocartiliginous callus and repair tissue bridges cartilage and collagen fibres.
Reparative phase - bony callus forms:
-In the healthy bone tissue area, osteoprogenitor cells develop into osteoblasts.
-Osteoblasts make trabeculae which join living and dead bone fragments, and convert
fibrocartilage to spongy bone.
-The fibrocartilaginous callus is now called the bony callus.
Bone remodelling phase:
- Osteoclasts resorb dead portions of the original fragments of broken bone.
- Compact bone replaces spongy bone at the periphery of the fracture.
What are the factors affecting
bone growth?
Dietary intake like minerals (calcium and phosphates) and vitamin D.
Hormones such as growth hormone, T3 and T4, parathyroid hormone, calcitonin that affect
bone growth and oestrogen which shuts growth at the epiphyseal plate.
Childhood associated hormones for bone growth: hGH, T3 and T4 and insulin.
Adult associated hormones for bone growth: increased release of sex steroids (androgen and
oestrogen).
Physical activity.
Genetics.
Race (African originated people have higher mineral bone density).
What factors affect the time
for bones to heal?
Age.
Bone broken.
Type of fracture.
Why do bones heal much
faster than cartilage?
Better blood supply.
How long does it take for a
fracture to heal in adults?
Weeks to months
What are the main 3 functions
of muscles?
Movement.
Support.
Heat generation.
What is the epimysium?
Connective tissue that surrounds the muscle bundle.
What is the perimysium?
Connective tissue that surrounds the fascicles.
What is the endomysium?
Connective tissue that surrounds the muscle fibres.
How does acetyl choline work in the
NMJ?
It is released at the pre-synaptic knob:
It diffuses across the synaptic cleft.
2 molecules bind to cholinergic nicotinic receptors on the post-synpatic membrane.
Acetylcholinesterase breaks ACh down.
How many subunits does AChR have?
5 subunits
Where does ACh bind to?
Two alpha subunits
What are the 2 types of AChR?
Nicotinic - Ligand-gated ion channel receptor.
Muscarinic - G-protein coupled receptor.
How are muscle fibres classified?
Speed of contraction: slow (type 1) fibres or fast (type 2) fibres.
Pathway used for generating ATP: oxidative phosphorylation or glycolysis.
What are the three types of muscle fibres?
Slow oxidative fibres - these are fatigue resistant and used for endurance.
Fast oxidative fibres - moderately fatigue resistant and used for sprinting.
Fast glycolytic fibres - fatigueable but with rapid powerful movements and are used in
weight lifting.
What are the two extremes of muscle
fibres and their characteristics?
Slow oxidative fibres: many mitochondria, dense capillary supply, high myoglobin
content, low myosin ATPase activity and small diameter.
Fast glycolytic fibres: few mitochondria, few capillaries, low myoglobin, high
glycogen content, high myosin ATPase activity and large diameter.
What is joint classification based on?
It is based on structural (type of connective tissue that joins bone) or functional
framework (degree of movement occurring in the joints).
What are the 3 main joint groups?
Fibrous joints.
Cartilaginous joints.
Synovial Joints.
What are fibrous joints?
They are joints that unite bones by fibrous tissue and permit no or very limited range
of movement.
What are the types of fibrous joints?
Include examples for each.
Syndesmoses fibrous joints - bones are joined by a sheet of a fibrous tissue band. Eg interosseous ligament/membrane joining the radius and ulna.
Sutures fibrous joints - interlocking projections of bone plates are joined by a thin layer
of fibrous tissue. Eg joints between plates of cranial bones.
Gomphoses fibrous joints - joints connected by a layer of fibrous tissue called the
periodontal membrane. Eg joint between root of tooth and alveolar process of mandible or maxilla.
What are cartilaginous joints?
They are joints where the bones are united by either hyaline cartilage or fibrocartilage which
permit very limited movement.
What are the types of
cartilaginous joints? Include
examples.
Synchondroses cartilaginous joints - bones that are joined by hyaline cartilage and is usually
temporary (occurs during the development of bones). Eg between epiphysis and diaphyses of long bones and articulation between
the first rib and sternum.
Symphyses cartilaginous joints - bones that are joined by a pad or a disk of fibrocartilage. Eg articulation between vertebrae and the articulation between the two hip
bones.
What are synovial joints?
They are freely movable joints that have a joint capsule, synovial membrane, articular
cartilage, joint cavity, articular discs, articular ligaments and an articular bursa.
What are the types of synovial
joints? Include examples.
Uniaxial joints - they permit movement around only 1 axis and in only 1 plane. Eg hinge joints and pivot joints.
Biaxial joints - they permit movement around 2 perpendicular axes and in 2 perpendicular
planes. Eg saddle joints and condyloid joints.
Multiaxial joints - they permit movement around 3 or more axes and in 3 or more planes. Eg ball and socket joints and gliding joints.
What are the 7 types of
arrangement of muscles fascicles?
Convergent e.g. Pectoralis major.
Circular e.g. Orbcularis oris.
Parallel e.g. Sartorius.
Unipennate e.g. Extensor digitorum longus.
Bipennate e.g. Rectus femoris.
Multipennate e.g. Deltoid muscle.
Fusiform e.g. Biceps brachii.
What is the agonist muscle?
It is the prime mover of a limb.
What is the antagonist muscle?
It is the muscle that antagonises the agonist.
What is synergestic muscle?
It is the muscle/muscles that contract to prevent unwanted movements or aid
the action of the agonist.
What are the 4 segments of the upper limb?
Shoulder.
Arm (from shoulder to elbow).
Forearm (from elbow to wrist).
Hand.
What are the 3 regions of the shoulder?
Pectoral region.
Scapular region.
Deltoid region.
What are the 2 regions of the arm?
Anterior aspect.
Posterior aspect.
What are the 2 regions of the forearm?
Anterior aspect.
Posterior aspect.
What are the 5 segments of the hand?
They are the anterior wrist, posterior wrist, palm/palmar region, dorsum and
the digits.
What are the signs of hypercalcaemia?
Stones - renal and biliary (bile ducts).
Groans - abdominal pain, nausea and vomiting.
Moans - depression, anxiety and insomnia.
Bones - bone pain.
Thrones - polyuria.
Confusion, drowsiness and comas.
What is an impacted fracture?
a fracture caused by a fall, strike from an object or by twisting action or bending of the bone.
What is a simple fracture?
a complete fracture, here the bone is broken into two fragments.
What is a hairline fracture?
a fracture caused by an acute event like a car crash or a fall, where the bone experiences a high force that causes the hairline to propagate.
What is a greenstick fracture?
a fracture where one side of the bone has broken and one side is bent. It is more common in children as their bones are more bendy and pliable.
What is a closed fracture?
a fracture where the broken bone does not penetrate the skin.
What is an open fracture?
a fracture where the broken bone penetrates the skin.
What is an avulsion fracture?
a fracture that occurs when a ligament or tendon pulls off part of a bone during an injury. It is more common in children than adults.
What is a compression fracture?
fractures when the vertebral body of the spine is compressed. It usually occurs in traumatic accidents and in patients with osteoporosis.
What is a multifragmentary fracture?
a fracture where the bone completely breaks into several fragments, resulting from very traumatic injuries.
What treatment is required for a multifragmentary fracture?
Requires pinning or plates to repair
What causes giantism?
Oversecretion of hGH in childhood or lack or undersecretion of oestrogens in childhood.
What causes acromegaly?
Oversecretion of hGH after closure of the bone growth (epiphyseal) plates.
What causes pituitary dwarfism?
Undersecretion of hGH in childhood.
What is osteoporosis?
Osteoporosis is a condition that weakens bones, making them fragile and more likely to break. It
develops slowly over several years and is often only diagnosed when a minor fall or sudden impact
causes a bone fracture.
What causes osteoporosis?
Old age. Diet. Menopause. Alcoholism. Genetics. Eating disorders. Many more such as rheumatoid arthritis, Crohn's/coeliac disease.
What causes brittle bones?
Decreased collagen synthesis
What causes osteomalacia (adult rickets)?
Lack of vitamin D, calcium or renal dysfunction
What are the signs of
adult
rickets/osteomalacia?
Soft and bending bones.
What are the signs of
rickets/child
osteomalacia?
Bowed legs, deformities of pelvis and rib cage.
What are spasms?
Sudden and involuntary muscle contractions, which are transient.
What are cramps?
Involuntary and tetanic muscle contractions.
What is muscle
atrophy?
Muscle wasting or decrease in muscle size/mass due to disuse.
What is muscle
hypertrophy?
Skeletal muscle growth afterbirth, which is influenced by exercise and hormones.
What is dystrophy?
Degeneration of tissue.
What is sarcopenia?
Reduction in muscle mass due to ageing, which is influence by hormones, poor diet, muscle disuse
etc
What are strains?
Muscle pain and inflammation caused by overuse or overstretching.
What are sprains?
Tearing of ligaments around a joint due to abnormal or excessive joint damage.
What is duchenne muscular dystrophy?
It is an X-linked inherited skeletal muscle fibre degenerative disease.
What causes duchenne muscular dystrophy?
Dystrophin, which provides structural strength, is absent, so muscle fibres break open.
What are the clinical signs of duchenne muscular dystrophy?
Muscle weakness and wasting, causing difficulty in getting up.
Gower’s sign.
What is Becker muscular dystrophy?
a more mild version of DMD that develops in adolescence.
What is myasthenia gravis?
An autoimmune disease that causes the break down of nicotinic cholinergic receptors.
What are the signs of myasthenia gravis?
Fatigue. Slurred speech. Weakness. Shortness of breath. Droopy eyelids.
How is myasthenia gravis treated?
Boost levels of ACh by AChE inhibitors or by using immunosuppressant drugs.
What is a colles fracture?
a complete fracture of the radius bone of the forearm close to the wrist resulting in an upward (posterior) displacement of the radius.
What are the signs of a colles fracture?
An obvious deformity and lump on the posterior aspect of the wrist. Pain. Swelling. Deformity. Bruising.
What is a smith’s fracture?
Fracture of the distal radius.
What causes a smith’s fracture?
It is caused by a direct blow to the dorsal for area or falling onto flexed wrists.
What are the signs of a smith’s fracture?
Swelling.
Pain.
Tenderness.
Bruising.
How is a smith’s fracture treated?
Cast
Surgery
What is tennis elbow?
lateral epicondylitis, which causes pain at the outside of the elbow.
What causes tennis elbow?
due to excessive use of the muscles of the back of the forearm. It’s common in tennis
players.
What are the signs of tennis elbow?
Pain on outside of the upper forearm just below the elbow.
Pain when lifting or being the arm.
Pain when lifting or bending the arm or when extending the arm or when twisting the arm.
How is tennis elbow treated?
Changing activity. Painkillers and NSAIDs. Physiotherapy. Steroid Injections. Shockwave therapy.
What is golfers elbow?
Medial epicondylitis of the humerus.
What causes golfers elbow?
Overuse of the arm, such as in weight training and forceful, repetitive occupational
movements like in construction, plumbing and carpentry.
What are the signs of golfers elbow?
Pain and tenderness.
Stiffness.
Weakness.
Numbness or tingling.
How is golfers elbow treated?
Changing activity. Painkillers and NSAIDs. Physiotherapy. Steroid Injections. Shockwave therapy.
What causes carpel tunnel syndrome?
The carpel tunnel swells, causing compression on the median nerve:
Overweight or pregnant.
Repeatedly using the hand.
Illnesses such as arthritis
What are the signs of carpel tunnel syndrome?
Ache or pain in the hand and forearm.
Numb or tingling hands.
Weak thumbs or difficulty gripping.
How is carpel tunnel syndrome treated?
Wrist splint.
Changing activity and hand exercises.
Painkillers, such as paracetamol and ibuprofen.
Surgery.
What causes Guyon’s canal syndrome?
The compression of the ulnar nerve in the Guyon’s canal from a hamate hook fracture, synovitis, repetitive
trauma (e.g. on handle bars), ulnar artery aneurysm or thrombosis and ganglion.
What are the signs of Guyon’s canal syndrome?
Paraesthesia and tingling of the little finger and ulnar side of the 4th (ring) finger.
Clawing of little and 4th finger.
Weakened grasp.
Abducted posture of the little finger (Wartenberg sign).
Hypothenar muscle wasting.
How is Guyons canal syndrome treated?
Surgery.
Changing activity and physiotherapy.
Splinting.
What are the signs of interosseus syndrome?
The thenar muscles are unaffected.
Paresis of the flexor digitorum and polices longus.
What is the test
for interosseous
syndrome?
The patient tries to make an ‘okay’ sign. If the patient can’t make an ‘okay’ sign, then they test positive for
interosseous syndrome. This is due to loss of flex ion at the interphalangeal joint of the thumb and the distal
interphalangeal joint of the index finger.
What are the
clinical signs of ulnar
nerve palsy?
The hand of Benediction.
Thenar muscle paralysis.
Wrist addiction is lost.
What are the
causes of ulnar
nerve palsy?
Medial epicondylitis fracture.
Cubital tunnel syndrome.
What is Erb’s palsy?
Paralysis of the arm.
What causes Erb’s palsy?
The severing of the upper trunk C5-C6 nerves:
Dystocia, an abnormal or difficult childbirth or labor. Common in mothers with diabetes where child grows really big due to large concentration of glucose in blood stream. The shoulders are too wide to fit out of
mother.
Injury to the head and shoulder like falling from a height onto head and arm.
Traction of the arm.
Bullet wounds.
What are the signs of Erb’s palsy?
Weakness in one arm. Decreased or lack of grip in affected hand. Numbness in arm or hand. Paralysis in arm. Pain on affected side.
