A&P Y1 Flashcards
Skeletal system functions?
Skeletal system functions?
.Supporting the body- protection for vital organs, soft tissues will attach onto. Holds the animal upright.
.Storage - storage of mineral particularly calcium & phosphorus.
. Production -red marrow produces red blood cell, white blood cells and other elements of blood. Produced in long bones. In young in all bones.
.Protection - rib cage for heart and lungs, skull for brain, vertebrae for spinal cord, pelvis for reproductive organs.
.Leverage of movement
From week 1 theory
Bone tissue?
.Bone tissue?
.has a strong roll in homeostasis because of the calcium stored in the bone.
.Calcium is needed for correct muscle function and need a constant reserve. Bone can release calcium into the blood stream when needed.
.Bone tissue also bone marrow red & yellow. Yellow stores lipids.
.larger at component of skeletal system and second cartilage
.Cane repair itself with osteoblasts cells.
.Bones can thicken and gain strength from regular exercise and a balanced diet. Horses can get bone splints from ever exercise in young race horses. Bones been strained too quickly. Lump form to help support tissue.
From week 1 theory
Bone classification?
Bone classification?
.Long bones - provide muscle attachement for joints. Involved in movement. Normally in limbs.
.Irregular bones - all different e.g. vertebrae, some in skull.
.Short bones - normally in-between joints. Horse short bones in carpus. High movement needed. Rotational movement.
.Flat bones - thin and flattened for protection of organs e.g. ribs, skull
.Sesamoid bones - over joints not forming. Provide strength to tendons and ligaments . E.g knee cap.
From week 1 theory
Bone tissue formed?
Bone tissue formed?
.Two components of bone tissue are cells and extracellular matrix that is a substance that surrounds the cells called ground substance and fibres.
.Extracellular matrix (non cellular) component filled the space between the cells. Secreted by bone cells. Made up of an inorganic and organic parts below
-Inorganic salts (ground substance) - larger 60% of bone weight in adults. Calcium carbonate and calcium phosphate give bone hardness and rigidity also flexibility so they don’t break as easy.
-Organic part (fibres) - 90% type 1 Collagen fibres give bone toughness, it allows pressure to be withstanded. These salts are deposited in a matrix of collagen fibres. 10% of organic composition non- collagenase proteins. Produce collagen fibres. Maintenance of bone tissue.
From week 1 theory
Histology of bone?
Histology of bone?
.Bone cells are responsible for development, maintenance and breakdown of bone tissue.
Types
.Osteogenic (Osteoprogenitor) cells - develops into an Osteoblast. Derived from mesenchyme (stem) cells that are able to multiple because they have osteogenic potential. It happened via the process of mitosis and differentiation into bone cells. Found in the periosteum and endosteum.
.Osteoblasts - First cells to developed from osteoprogenitor cells. regenerate bone when needed. They cover majority of bone surface in huge numbers. forms bone tissue. Secrete extracellular matrix. Formation of organic matrix - osteoid . Bone development - while bones are in their osteoblast stage they are responsible for secreting osteoid that will then be calcified and mineralised to form the extracellular matrix and the bone tissue. High rate of metabolism. Abundant ER, ribosomes, golgi apparatus, mitochondria.
.Osteocytes - once osteoblasts have matured (produces osteoid ect) they become osteocytes . maintains bone tissue. Fewer metabolic activity.
.Osteoclasts - functions in resorption, the destruction of bone matrix when needs to be replaced. Large multinucleated cells (more than one nucleus). Near bone surface. Derived from macrophages (immune cell) and are taken to the bone tissues by blood vessels and detect bone that needs to be broken down then osteoclasts secrete hydrogen ions that create an acidic environment that will dissolve minerals, salts within the bone matrix and remove organic matrix these process brokers down the bone tissue needed to be replaced. Functions - only carried out when bone tissue needs replacing. needs to work with the osteoblasts to form new bone. If over active can cause osteoporosis - this brakes down bone tissue too quickly.
From week 1 theory
Bone structure types?
Bone structure types?
Two types below
.Cortical (compact, hard bone) -Made up of osteons. Looks like lots of rings around circles on bone under microscope. These circles are the lamellae layers forming a cylinder of bone matrix. All of the layers are called Lamellae (hollow cylinders) forming one matrix tube and fit together to form a osteon.
.Cancellous (spongy, traecular bone) - In-between trabeculae (holes) is red marrow (haematopoietic) that is red blood cells or yellow (fatty) marrow that is a reserve for fat. Made up of trabeculae. Looks like holes within bone.
.Flat bones - layer of hard bone on the inside, then they have a layer of spongy bone and then another layer of hard bone on the outside.
.Irregular bones - are mainly spongy bone with a thin layer of compact bone on the outside.
.Long bones - spongy at ends and compact in the middle.
.Short bones are mainly spongy bone and covered by compact bone on the outside.
From week 1 theory
Compact bone?
Bone structure - compact bone?
.Structural unit - osteon or haversian system.
.Made up of a number of repeating units we call osteon (haversian system). Osteon are a hollow cylinder bone matrix and they all fit together.
.Looks like lots of rings around circles on bone under microscope. These circles are the lamellae layers forming a cylinder of bone matrix. All of the layers are called Lamellae (hollow cylinders) forming one matrix tube and fit together to form a osteon.
.Lamellae - lines run in 90 degree angle. Line run In opposite direction to the next lamellae.
.Osteon - are formed in the lamellae tube way because the upright position gives it extra support. Thousands of tubes along with collagen fibre provide toughness to bone.
.Central (haversian) canal - a hole in the middle of the Osteon. This hole (canal) allows blood vessels, nerve fibres to pass through the Osteon.
.Lacuna - the dots seen under microscope seen on compact bone. Small holes and they contain the osteocytes within them.
.Volksmann’s canal - they connect the different osteons together to provide a blood supply from the periosteum (on outside of bone) into the central/ haversian canals.
.Canaliculi - are small channels that connect the osteocytes to the central/ haversian canal. They connect the lacunae and central canal for nutrient and waste distribution.
.Endosteum - covers outer inside of compact bone in the middle (the part that touches the medullary cavity). Stem cells lie within this the endosteum and periosteum.
From week 1 theory
Spongy (Cancellous) bone?
Spongy (Cancellous) bone?
.Made up of trabeculae looks like a sponge. Arranged in this way to provide max strength and can arrange them self for strain and stress areas.
.Within the trabeculae they still have Lamellae in them and have the osteocytes in the lacunae in the same way as the compact bone does.
.Canaliculi are present that provide communication network and allow the osteocytes to receive nutrients and blood they need.
.Within spongy bone the bone tissue will vary in quantity from about 10% - 70% depending on where the bone.
.Within the holes and gaps is where the high about of yellow and red bone marrow.
From week 1 theory
Long bone structure?
Long bone structure?
.Proximal epiphysis (top) - spongy bone. Generally sit within joint capsules and joint cavities and need to be able to glide over one another for the joint to be able to function effectively. The articular cartilage covering the epiphyses has a smooth surface that allows this to happen.
.Diaphysis (middle) - is made up of compact bone and inside the centre of the compact bone is the medullary cavity and this contains bone marrow.
.Distal epiphysis (bottom) - spongy bone. Generally sit within joint cavities and need to be able to glide over one another for the joint to be able to function effectively. The articular cartilage covering the epiphyses has a smooth surface that allows this to happen.
From week 1 theory
Periosteum?
Periosteum?
.Surface membrane connective tissue that covers all outside of bones.
From week 1 theory
Foetal skeleton?
Foetal skeleton?
.Earliest stages of development begins with a cartilaginous tissue framework then the stem (mesenchymal) cells will start to turn (differentiate) into chondrocytes (mature cartilage cells). That’s what form the cartilage model of the skeleton.
.During the second half of embryo genesis (foetal development) the bones will under go the process called endochondral ossification. The extracellular matrix of this cartilage will start to form intermediary cartilage tissue that form the frame of the skeleton.
.These chondrocytes will start to grow and then the tissue will become vascularised (start to get a blood supply) to the cartilage frame and that will transport osteoclasts (cells that breakdown tissue) will start to break down the cartilaginous matrix and in its place we start to see osteoblasts that form bone tissue instead. That is the process of ossification.
From week 1 theory
Bone development stages?
Bone development stages?
.Primary ossification will happen within the diaphysis (centre) of long bones becoming bone tissue first then spreads along the rest of the diaphysis.
.Secondary ossification - happens later on in the distal & proximal epiphyses of the bones.
.Epiphyseal plate - is formed from cartilage remaining between the expanding primary and secondary ossification centres (plate separating the epiphyses and diathesis).
.Articular cartilage - on the outside of the epiphyses. Will remain throughout maturity. Is a layer of cartilage. Provides a smooth surface for the ends of bones so joints can easily glide over each other.
From week 1 theory
Ossification?
Ossification?
.Bone forming by osteoblasts.
From week 1 theory
Bone development stages?
Bone development stages?
1) Hyaline cartilage framework (foetal)
2) Primary ossification centre inside the medullary cavity that expands the length of the diaphysis.
3) Secondary ossification centre in the proximal & distal epiphyses.
After you’re left with compact bone in the diaphysis shaft, spongy bone in the epiphyses, epiphyseal plate dividing the two and the articular cartilage covering the ends of the bones.
From week 1 theory
Epiphyseal (growth) plates?
Epiphyseal (growth) plates?
.Reason - allows elongation of the bones and bone development to continue.
.Young animal - have the epiphyseal plates remaining to allow for elongation and growth of the bones. They will continue to grow and develop through the process of mitosis (cellular multiplication) we will get more cartilaginous tissue growing in that region.
.As the animal matures, near the edges of the epiphyseal plates will start to ossify and we will get new bone formation.
.New bone formation increasing the length of the shaft at both ends.
.Thickness of the physis decreases as the cartilage is broken down for ossification ending the bone lengthening process. It can no longer grow and expand but Can still see bones growing in thickness and diameter when under stress
.Periosteal (appositional) - bone grows in thickness not in length.
.Endosteum - osteoclasts on here will be breaking down old bone on the inside but the medullary cavity will stay the same size.
From week 1 theory
Medullary cavity?
Medullary cavity?
.Inside the middle of compact bone. Contains bone marrow and means the bone is lightweight.
From week 1 theory
The axial skeleton?
The axial skeleton?
.Skull - Incisors, molars, incisive bone, nasal bone, frontal bone, Temporomandibular joint, Occiput, Temporal bone, facial crest, mandible, maxilla.
.Vertebrae column - equation cervical (C7), thoracic (T18), lumbar (L6) L5 in Arabs, sacral (S5), coccygeal (C15-20). Protects the spinal cord and allows attachments for muscles and tendons to support the weight of the body e.g has to hold the abdominal cavity up in the horse.
.Ribs and sternum
From week 1 theory
The appendicular skeleton?
The appendicular skeleton?
.Bones that bring about locomotion
.Shoulder blade
.Pelvic
.Limbs
.Thoracic (forelimb) limb -a shock absorber and a weight carrying limb. Approx 60% of their weight is distributed to the forelimbs. Straighter than hind limbs for more support.
.Pelvic (hind) limb - approximately 40% of body weight support. Main function is creation of power of locomotion. They are the driving force that push the animal forwards.
From week 1 theory
Intervertebral discs?
Intervertebral discs?
.Approximately 10% of the length of the spine.
.Cartilage in-between the vertebrae
.Acts as a shock absorber, cushioning the vertebrae from damage e.g. when running.
From week 1 theory
Rib cage?
Rib cage?
.Sternum - ventral part of rib cage. First 8 (true) ribs articulate with the sternum directly by forming a bony attachment.
The other 10 (false ribs) have an indirect attachment, they are attached via costal cartilage attachment between the ribs and the sternum.
.Rib-head, body, costochondral junction, costal cartilage.
.Articulate with thoracic vertebrae
.Articulate with sternum either directly or indirectly
From week 1 theory
Articulation?
Articulation?
.An articulation, or joint is usually formed of fibrous connective tissue and cartilage.
From week 1 theory
Further reading?
Further reading?
E-book on wuc library
.Chapter 4: the skeletal system in anatomy and physiology of farm animals (fails and magee, 2018)
-functions of bones
-terminology
-classification of bones according to gross appearance
From week 1 theory
Body movement?
Body movement?
.Body movements happen when muscles contract across joints, moving one bone towards another.
From week 1 theory bones video on moodle
Joint types?
Joint types
3 Types;
-Fibrous joints - connect bones with dense fibrous connective tissue. No joint cavity. They don’t move e.g in skull.
-Cartilaginous joints - connect bones with cartilage. Don’t move very much. No joint cavity. 2 types - synchondroses and symphyses.
-Synovial joints - freely moveable.
6 special features;
.Articular cartilage that covers the opposing bone surfaces
.Band-like ligaments
.A joint cavity filled with fluid
.Synovial fluid lubricant (acts like grease on a hinge).
.A fibrous joint capsule
from week 1 theory Bones video on moodle
How much joints can move
How much joints can move
.Synarthroses - non-moving joints e.g surface of skull.
.Amphiarthroses - partly-moving joints e.g. pelvic area.
.Diarthroses - fully movable joints e.g. limbs
from week 1 theory Bones video on moodle
Synovial joints?
Synovial joints?
Structure Types;
.Plane joint - unite bones using cartilage (they use gliding movements)
.Hinge - uniaxial movement
.Condylar - biaxial movement
.Pivot - uniaxial movement
.Ball and socket - multiaxial movement (rotational movement) the more flexible a joint is, the more unstable and fragile it is.
.Saddle - biaxial movement e.g hands and feet.
from bones video on moodle week 1 theory
Identify the scientific anatomical names?
Identify the scientific anatomical names?
- Fetlock = metacarpophalangeal and metatarsophalangeal joints
- Long Pastern = Proximal phalanx
- Pedal bone = distal phalanx
- Hock = Tarsus Joint
From week 1 practical sheet
Identify the layman’s terms
Identify the layman’s terms
- Middle phalanx = short pastern
- Metacarpophalangeal joint = fetlock
- Mandible = lower jaw
- 3rd Metatarsal bone = cannon bone
from week 1 practical sheet
Give definitions for the following anatomical terms:
Give definitions for the following anatomical terms:
- Proximal = situated nearer to the point of attachment
- Distal = situated away from the point of attachment
- Medial = situated near the median plane of the body or the midline of an organ
- Lateral = away from the midline of the body (side)
- Dorsal = the back or upper side of an organism or parts of an organism
- Ventral = bottom half and include the chest, abdomen, shins, palms, and soles
- Cranial = towards the head
- Caudal = towards the tail
from week 1 practical sheet
Give an example of each of the following in the equine skeleton
Give an example of each of the following in the equine skeleton
• A long bone = femur
• A short bone = carpal bone
• A flat bone = scapula
• An irregular bone = pelvic bone
• A sesamoid bone = there are two in the horse. Proximal are found at the back of the fetlock or metacarpophalangeal and metatarsophalangeal joints and the distal sesamoid bone (navicular bone) is behind the pedal bone.
From week 1 practical sheet
2nd, 3rd, 4th metacarpal and tarsal bones are
2nd, 3rd, 4th metacarpal and metatarsal bones are
2nd and 4th = splint bones
3rd = Cannon bone
From week 1 practical sheet
Stifle joint
Stifle joint
.Patella bone (kneecap) infront of it
Skeletal structures on a horse for exam
Skeletal structures on a horse for exam
• Cranium
• Mandible
• Cervical vertebrae (first and last vertebrae)
• Thoracic vertebrae (first and last vertebrae)
• Lumbar vertebrae (first and last vertebrae)
• Sacral vertebrae (first and last vertebrae)
• Caudal vertebrae (first and last vertebrae)
• Scapula
• Humerus
• Sternum
• Elbow joint
• Radius
• Ulna
• Carpus
• 2nd, 3rd 4th Metacarpal bones
• Metacarpophalangeal joint
• Proximal sesamoid bones
• Proximal phalanx
• Middle phalanx
• Distal phalanx
• Distal sesamoid bone (navicular bone)
• 1st -18th rib
• Ilium = part of hip bone
• Tuber ischium = part of pelvis
• Tuber coxae = part of pelvis
• Tuber sacrale = part of pelvis
• Hip joint
• Femur
• Patella
• Stifle
• Fibula
• Tibia
• Tarsus
• 2nd, 3rd , 4th Metatarsal bone
From week 1 practical sheet
Muscle Function
Muscle Function
- Produce movement
- Maintain posture
- Stabilise joints
- Control cavity pressures
- Maintain body temperature
- Energy Storage
- Control entrance and exits to body
From week 2 lecture
Muscle Types
Muscle Types
.Smooth
.Cardiac
.Skeletal
From week 2 lecture
Smooth Muscle
Smooth Muscle
AKA:
.Nonstriated
.Involuntary muscle
Surrounds:
.Blood Vessels
.Digestive tract
.Urinary system
.Reproductive system
.Respiratory system
.Involuntary movement
From week 2 lecture
Cardiac Muscle
Cardiac Muscle
Composed of cardiac muscle cells:
.Cardiomyocytes/Cardiocytes
.Contracts without nervous stimulation
.Striated
.Fatigue resistant
From week 2 lecture
Skeletal Muscle
Skeletal Muscle
.Striated
.Voluntary control
.Movement
From week 2 lecture
Skeletal Muscle Gross structure
Skeletal Muscle Gross structure
.Origin
- Least moveable
.Body
- Contracts
.Insertion
- Moveable
From week 2 lecture
Basic Structure of Skeletal Muscle
Basic Structure of Skeletal Muscle
Belly:
.Many muscle cells
.Connective tissue between muscle fibres
.Nerves throughout
.Photo on laptop
From week 2 lecture
Skeletal Muscle Organisational Hierarchy
Skeletal Muscle Organisational Hierarchy
.Skeletal muscles have a hierarchical structure
.The muscle (organ) is composed of fascicles
.Fascicles are composed of fibres
From week 2 lecture
Skeletal Muscle Fibres
Skeletal Muscle Fibres
.Long, multinucleated cell
.Visible striations
.Sarcolemma
- Tubular sheath which envelops the fibres of skeletal muscles.
.Myofibrils
- Elongated protein strands with thick and thin filaments
From week 2 lecture
Skeletal Organisational Hierarchy
Skeletal Organisational Hierarchy
.Fibres are composed of myofibrils
- Arranged in parallel
.Myofibrils are composed of sarcomeres
- Arranged end to end
.Sarcomeres are the functional unit of the muscle cell
from week 2 lecture
Skeletal Muscle Tissues
Skeletal Muscle Tissues
Three connective tissue layers;
.Epimysium
.Perimysium
.Endomysium
From week 2 lecture
Skeletal Muscle – fibre alignment
Skeletal Muscle – fibre alignment
.Parallel – ‘strap muscle’
- Greatest potential for muscle shortening
- Relatively weak
.Pennate/penniform
- Increased power
- Less distance to contract
- Unipennate
- Bipennate
- Multipennate
From week 2 lecture
Skeletal Myofilaments
Skeletal Myofilaments
.Actin
- Thin filaments
- Double helix
- Myosin binding site
.Myosin
- Thick filaments
- Multiple chains
- Globular heads
- Bind to Actin
Myofilaments don’t shorten, simply slide over each other
From week 2 lecture
The Sarcomere
The Sarcomere
.Is the contractile unit of muscle
.Muscle contracts (shortens)
.Then relaxes (lengthens)
From week 2 lecture
Muscle contraction
Muscle contraction
.Rest
- Thick and thin filaments do not overlap completely
.Contraction
- Length of sarcomere is reduced
- A bands don’t change length
- I bands shorten
- H zone disappears
.Sliding filament theory
- Thick and thin filaments don’t change shape
- Degree of overlap increases
.Myofibril:A cylindrical organelle running the length of the
muscle fibre, containing Actin and Myosin filaments.
.Sarcomere: The functional unit of the Myofibril, divided into I, A and H bands.
.Actin: A thin, contractile protein filament, containing ‘active’ or ‘binding’ sites.
.Myosin: A thick, contractile protein filament, with protrusions known as Myosin Heads.
.Tropomyosin:An actin-binding protein which regulates muscle contraction.
.Troponin:A complex of three proteins, attached to Tropomyosin.
.Sarcoplasmic Reticulum: A specialised type of smooth ER that regulates the calcium ion concentration in the cytoplasm of striated muscle cells.
From week 2 lecture
Tropomyosin and troponin
Tropomyosin and troponin
.Tropomyosin
- Rod shaped protein
- Regulatory protein in thin filament
- Blocks actin’s active sites
.Troponin
- Helps position tropomyosin to actin
- Binds calcium ions
.Both help control myosin – actin interactions
From week 2 lecture
Muscle contraction
Muscle contraction
Step 1: Anervous impulsearrives at the neuromuscular junction, which causes a release of a chemical called Acetylcholine.Acetylcholine causes the depolarisation of the end-plate, causing calcium ions (Ca2+) to be released from the sarcoplasmic reticulum into the sarcoplasm. The presence of Acetylcholine causes the depolarisation of the motor end plate which travels throughout the muscle by the transverse (T) tubules, causing Calcium (Ca+) to be released from the sarcoplasmic reticulum within the muscle fibre into the sarcoplasm of the muscle fibre.
Step 2: In the presence of high concentrations of Ca2+, the Ca2+ binds to Troponin, changing its shape and so moving Tropomyosin from the active site of the Actin.The Myosin filaments can now attach to the Actin, forming a cross-bridge.
In order for myosin filaments to be able to attach to the actin, they need to be activated. This happens when a molecule of ATP binds to the myosin head. This is hydrolysed into ADP and inorganic phosphate. The energy from this reaction lifts the myosin head into the cocked position to form a cross-bridge.
Step 3: The breakdown of ATP releasesenergywhich enables the Myosin to pull the Actin filaments inwards and so shortening the muscle.The contraction of myosin’s S1 region is called the power stroke. The power stroke occurs when the ADP and inorganic phosphate molecules are released.
This occurs along the entire length of every myofibril in the muscle cell.
Step 4 & 5: The Myosin detaches from the Actin and the cross-bridge is broken when an ATP molecule binds to the Myosin head.When the ATP is then broken down the Myosin head can again attach to an Actin binding site further along the Actin filament and repeat the ‘power stroke’.
Freom week 2 lecture notes
Sliding filament theory
Sliding filament theory
.Interaction between Actin and Myosin molecules
.Myosin head centre for reactions
- Binding to and hydrolysing ATP to ADP
.Energised Myosin binds to Actin forming cross bridge
.What causes filaments to slide?
- Attachment myosin head to binding sites on thin filaments and sliding begins.
- Each cross bridge attaches and detaches several times during contraction, generating tension that helps to pull the thin filaments toward the centre of the sarcomere.
- As this occurs simultaneously in sarcomeres throughout muscle cell, cell shortens.
.Based on the interaction of the actin & myosin molecules that make up the thick & thin filaments
Myosin consists of a long fibrous tail region with a globular ‘head’ sticking off to the side
The tail is where the individual myosin molecules join together to form the thick filament
The myosin head is the centre for the reactions that power muscle contractions
It does this by binding to & hydrolysing ATP to ADP with the resultant release of energy
Energised myosin binds to a specific site on actin forming a cross-bridge
From week 2 lecture
Sliding filament theory steps
Sliding filament theory steps
.Release stored energy
.Relaxation myosin head
.Change of angle of attachment
.Myosin bends in on itself
.Tension on actin filament
.Pull actin filament to centre sacromere
The stored energy is released which causes the myosin head to relax. This relaxation changes the angle of attachment of the myosin head to the myosin tail. As the myosin bends in on itself, it exerts tension on the thin actin filament to which it is bound. Hence it pulls the thin filament to the centre of the sarcomere. The bond between the low energy myosin and the actin is broken when a new molecule of ATP binds to the myosin head. The cycle repeats and the newly energised head can now contract again.
From week 2 lecture
Sliding filament theory
Sliding filament theory
.Thick filament – approx 350 heads
.Form and re-form 5 cross bridges / sec
.NB: Myofilaments don’t shorten
.It can now attach to a new binding site on another actin molecule farther along the thin filament
Each thick filament has approximately 350 heads
Each head can form and re-form about 5 cross bridges per second, driving filaments past each other
A muscle cell will only store enough ATP for a few contractions
Some myosin heads will always be in touch with actin to avoid thin filaments sliding backward
Myofilaments don’t shorten, simply slide over each other
Week 2 lecture
Functional Classification
Functional Classification
.Flexors - aims to close a joint angle
.Extensors- aims to open a joint angle
.Adductors- towards midline
.Abductors - away from midline
.Agonist – prime mover, provides major force
.Antagonist – works against another muscle, e.g. bicep and tricep
.Synergist – helps support movement e.g. brachialis to biceps brachii in flexing elbow
From week 2 lecture video part 1
Types of Contraction
Types of Contraction
.Isotonic
- Concentric
- Eccentric
- Antagonistic against larger force
.Isometric
- Stationary contraction against resistance
.Concentric
- Duringconcentric contraction, the biceps shortens and pulls the weight towards theshoulder joint.
.Two situations can lead to aneccentric movementfrom this point;
- The biceps is loaded with aforce greater than the one it
produced during concentric contraction (e.g. more weight
added to the dumbbell).
- You intentionally start relaxing your biceps.
.In both situations, the force produced by the muscle is insufficient to hold the biceps brachii in a fully contracted state. This will cause the muscle fibers toforcefully lengthen, which is called eccentric contraction.
From week 2 lecture
From week 2 lecture notes
Bicep
Bicep
.Aims to flex the elbow.
.Brachial policy helps to support the bicep.
From A&P Muscle Tissue Week 2 (Part 1) video
Tricep
Tricep
.Aims to extend the elbow
From A&P Muscle Tissue Week 2 (Part 1) Video
Skeletal muscle insertion
Skeletal muscle insertion
.Some muscles share the same insertion site but have their own origins.
From A&P Muscle Tissue Week 2 (Part 1) Video
Skeletal muscle origins
Skeletal muscle origin
.Is the part where the nervous impulse starts and brings the insertion closer to the origin during a contraction.
From A&P Muscle Tissue Week 2 (Part 1) Video
Skeletal muscle terminology
Skeletal muscle terminology
.Hypertrophy - a large linning of the fibres.
.Hyperplasia - increase in amount of fibres present
From A&P Muscle Tissue Week 2 (Part 1) Video
ATP?
ATP
.Provides energy for contraction
.Decrease in available ATP causes fatigue.
From week 2 lecture video part 2
Tone?
Tone?
.Tension within muscles at rest
. Involuntary
.Prevents paralysis with nervous systems help.
From week 2 lecture video part 2
Smooth muscle?
Smooth muscle?
.No striations
.Fusion form cell - it’s spinal shape helps it perform peristalsis
.Central nucleus
.Nerve type - mechanical and electrical
.Ca2+ needed for contraction and relaxation.
.Smooth muscle cells - respond to stimuli with relaxation or contractions. starts from mechanical stimuli (stretch) e.g. food.
From week 2 lecture video part 2
Cardiac muscle
Cardiac muscle
.Striations and lines
.Intercalated discs
.Electrical transmission
.Loads of ATP production
.Excitation and contraction
.Calcium needed for contraction
From week 2 lecture video part 2
Extensors of the shoulder
Extensors of the shoulder
.Brachiocephalicus muscle - Is the extensor of the shoulder. It raises and advances the shoulder.
.Supraspinatus muscle - May assist in extending the shoulder but acts chiefly as a stabilising muscle of the shoulder joint.
From Fails and Magee (2018) ‘Anatomy and Physiology of Farm Animals. Chapter 7, page 131.
Flexors of the shoulder
Flexors of the shoulder
.Latissimus dorsi - Very strong flexor of the shoulder.
.Infraspinatus - may flex, abduct and outwardly rotate the shoulder.
.Deltoideus - flexor and abductor of the shoulder joint.
From Fails and Magee (2018) ‘Anatomy and Physiology of Farm Animals. Chapter 7, page 132.
Adductors of the shoulder
Adductors of the shoulder
.Pectoral muscles - strong adductors of the forlimbs
From Fails and Magee (2018) ‘Anatomy and Physiology of Farm Animals. Chapter 7, page 132.
Extensor of the elbow
Extensor of the elbow
.Tricep brachii - strongest extensor of the elbow. Can also flex the shoulder.
From Fails and Magee (2018) ‘Anatomy and Physiology of Farm Animals. Chapter 7, page 132.
Flexors of the elbow
Flexors of the elbow
.Bicep brachii - chief action flexion of the elbow but can extend it also.
.Brachialis - strictly a flexor of the elbow
From Fails and Magee (2018) ‘Anatomy and Physiology of Farm Animals. Chapter 7, page 133.
Extensors of the carpus
Extensors of the carpus
.Extensor carpi radialis - largest extensor of the carpus
.Extensor carpi ulnaris (Ulnaris lateralis) - can also flex the carpus
From Fails and Magee (2018) ‘Anatomy and Physiology of Farm Animals. Chapter 7, page 133.
Flexors of the carpus
Flexors of the carpus
.Flexor carpi radialis
.Flexor carpi ulnaris
From Fails and Magee (2018) ‘Anatomy and Physiology of Farm Animals. Chapter 7, page 134.
Extensors tendon of the digit
Extensors tendon of the digit
.Digital extensor muscle (extensor digitorium communis) - extensor of all joints of the digit including the metacarpophalangeal joint (fetlock) and may assist in extending the carpus and in flexion of the elbow.
From Fails and Magee (2018) ‘Anatomy and Physiology of Farm Animals. Chapter 7, page 134.
Flexors tendon of the digit
Flexors tendon of the digit
.Deep digital flexor (flexor digitorum profundus)
From Fails and Magee (2018) ‘Anatomy and Physiology of Farm Animals. Chapter 7, page 135.
suspensory ligament
Suspensory ligament
.Connective tissue instead of muscle like most animals. Origin from the palmar aspect of the proximal metacarpus and insert on the proximal sesamoid bones.
.It supports the metacarpophalangeal joint.
From Fails and Magee (2018) ‘Anatomy and Physiology of Farm Animals. Chapter 7, page 135.
extensors of the hip
extensors of the hip
.Biceps femoris
.Semimembranous
.Middle gluteal muscle
From Fails and Magee (2018) ‘Anatomy and Physiology of Farm Animals. Chapter 7, page 141.
flexors of the hip
flexors of the hip
.Rectus femoris
.Iliacus
.Psoas major
.Sartorius
From Fails and Magee (2018) ‘Anatomy and Physiology of Farm Animals. Chapter 7, page 141.
extensors of the stifle
extensors of the stifle
.quadricep femoris - insert on the patella and are the primary extensor of the stifle. includes rectus femoris as one of the heads etc
From Fails and Magee (2018) ‘Anatomy and Physiology of Farm Animals. Chapter 7, page 142.
flexors of the stifle
flexors of the stifle
.Bicep femoris
.semitendinosus
.semimembranosus
From Fails and Magee (2018) ‘Anatomy and Physiology of Farm Animals. Chapter 7, page 142
Tissue types
Tissue types
.Epithelial - Covers & protects body from environment
.Nervous - Controls body activities
.Muscle - Movement by contraction
.Connective - Supports & holds structures together
From week 3 lecture
Connective tissues types
Connective tissues types
.Skin
.Blood
.Bone
.Tendon - take longer to heal as poor blood suppy
.Ligament - take longer to heal as poor blood suppy
.Cartilage - doesn’t heal as has no blood supply
.Fascia - under skin and around organs
From week 3 lecture
Classification of Connective Tissue
Classification of Connective Tissue
.Embryonic
.Specialised
.Proper
-Loose irregular
-Dense regular
-Dense irregular
From week 3 lecture
Structure of Connective Tissue (CT)
Structure of Connective Tissue (CT)
.A supporting tissue with a wide range of forms, roles and functions.
.Composed of:
-Cells
-Fibres - extracellular matrix
-Ground substance- extracellular matrix
.Most fixed cells
- Tend to synthesise (make) and maintain the extracellular
matrix (ECM) in which they sit.
- Most common connective tissue cell = fibroblast (immature
or “precursor” cell)
- Also: Chondroblasts, osteoblasts, adipocytes (fat cells)
.Also migrating immune cells
-e.g. mast cells, macrophages, plasma cells
From week 3 lecture
Structure of connective tissue Fibres
Structure of connective tissue Fibres
1) Collagen fibres (most abundant protein in body)
-Provide tensile strength
-Produced by fibroblasts
-Form bundles (3 types)
2) Elastic fibres
-Provide stretching and recoil
-Form cross-linked networks
3) Reticular fibres
-Provide a supporting framework for organs
From week 3 lecture
Structure of Connective tissue Ground Substance
Structure of Connective tissue Ground Substance
.Semi-fluid gel “glue”, Colourless and transparent
-Carbohydrate (sugar) molecules called “polysaccharides”
-Form chains called “glycosaminoglycans” = GAG chains
-GAG chains attach to core protein, forming “proteoglycans” -
looks like a hair brush.
-These bristley structures knot together forming “glycoproteins”.
Functions:
-Traps water, which then resists compression (think jelly!)
-Also provides gel/fluid for nutrients to diffuse through
From week 3 lecture
The Extracellular Matrix = Ground Substance + Fibre
The Extracellular Matrix = Ground Substance + Fibre
Ground Substance
.Glycosaminoglycans (GAGs)
.Proteoglycans
.Glycoproteins
Role of ground substance:
-Diffusion
-Nutrients
-Resistance to compression
Fibres
.Collagenous (white)
.Elastic (Yellow)
.Reticular
Role of Fibre:
-Tensile Strength
-Elastic Recoil
-Defined Structure
From week 3 lecture
Dense Regular Connective Tissue
Dense Regular Connective Tissue
.Regular collagen bundles
.Tightly packed cells
.High tensile strength
.Protection mechanisms are common
From week 3 lecture
Tendons (Dense Regular connective Tissue)
Tendons (Dense Regular connective Tissue)
.Connect muscles to bone
.High tensile strength
.Taut when muscle contracts
.Slackens during muscle relaxation
.Poor blood supply
From week 3 lecture
Ligaments (Dense Regular connective Tissue)
Ligaments (Dense Regular connective Tissue)
.Connect bone to bone
.High tensile strength
.Always remains taut!
.Poor blood supply
.Less elastin than tendons
.Microstructure similar to tendons
.Cells known as desmocytes.
.Cellular component greater than tendons
From week 3 lecture
Bone Tissue (Specialised Connective tissue)
Bone Tissue (Specialised Connective tissue)
.Calcium carbonate and calcium phosphate (inorganic)
- 60% of bone weight in adults.
- These salts are deposited in a matrix of collagen fibers
(organic) - Salt crystals give bone hardness and rigidity.
Collagen fibers give bone toughness.
From week 3 lecture
Cartilage (Specialised Connective tissue)
Cartilage (Specialised Connective tissue)
Types;
.Hyaline, elastic, fibrous
.Highly specialised connective tissue
.Single cell type – Chondrocyte
.Secretes a rubbery matrix
.Ground substance – chondroitin
From week 3 lecture
Hyaline Cartilage
Hyaline Cartilage
.Most common
.Synovial joint surfaces (articulating surfaces)
.Blueish white appearance
.AKA articular cartilage
.Nose, ears, trachea etc
From week 3 lecture
Joints function
Joints function
.Articulations between adjacent bones that enable movement
From week 3 lecture
Joint Structural Classification
joint Structural Classification
.Fibrous joints
- dense connective tissue
.Cartilaginous joints
-Cartilage union
.Synovial joints
-Fluid filled cavity between bones
From week 3 lecture
Joint Functional Classification
Joint Functional Classification
.Synarthroses
-NO joint movement
Amphiarthroses
-Small amount of joint movement
.Diarthroses
Wide range of joint movement (Monoaxial, biaxial, triaxial)
From week 3 lecture
Fibrous joints
Fibrous joints
.Bones joined by fibrous tissue
.3 types;
.Sutures
– overlapping or interlocking
.Syndesmoses
– connected by fibrous tissue
.Gomphoses
– peg-in-socket
.Sutures & Gomphoses - Immovable joints. Junctions between bones filled by a small amount of fibrous connective tissue.
.Syndesmoses - amphiarthroses, fibrous connections,
not designed for mobility.
From week 3 lecture
Cartilaginous joints
Cartilaginous joints
.Bones united by cartilage
.Most slightly movable
2 types:
.Synchondroses - sites of bone growth. Connected by hyaline cartilage membrane. Mostly temporary - Epiphyseal plates of developing bones. Some permanent.
.Symphyses - articular surfaces covered with fibrocartilage. Fibrocartilage connection. Shock absorption. Pelvic symphysis and intervertebral joints.
From week 3 lecture
Synovial joints
Synovial joints
.Articular cartilage
.Joint cavity
.Joint capsule
.Synovial fluid
.Reinforcing ligaments
.Inner membrane secretes synovial fluid
.Joint capsule fibrous and continuous with periosteum
- Contributes to joint stability
- Composed of collagen
- Highly vascularised
- Afferent pain receptors
From week 3 lecture
Types of synovial joints
Types of synovial joints
.Hinge = Folding movement - metacarpophalangeal joint,
Ginglymus joint.
.Plane / gliding = Sliding movement - intercarpal joints,
Arthrodial joint.
.Pivot = Monoaxial, Rotation movement - atlantoaxial joint.
.Condyloid = Biaxial movement - antebrachiocarpal joint,
Knuckle shaped surface.
.Saddle
.Ball and socket = Wide ranging, Triaxial, multidirectional - coxofemoral.
From week 3 lecture
Synovial Joints stability maintained by
Synovial Joints stability maintained by
.Shape
.↑ surface area
.Surrounding muscle
.Intra articular ligaments
.Lateral & medial collateral ligaments
.Negative hydrostatic pressure.
From week 3 lecture
Ligaments
Ligaments
.Ligaments - Capsular, Extra-capsular, Intra-capsular
.Fat pads
.Bursae
Why are ligaments in / around a joint?
-Tough and unyielding
-No resistance to normal joint movement
-Prevent excessive / unnatural joint movement
-Become taught at normal limit of ROM
-Cross-fibre structure limits of elasticity
From week 3 lecture
Stifle Joint
Stifle Joint
.One of the most complex joints in the horse. Ability to ‘lock’
allowing one limb to rest.
.Surrounded by - ligaments to secure and stabilise.
.Menisci (fibrocartilage disks)
.Femorotibial joint
- Ginglymus joint
- Uniaxial. Slight abduction/adduction and rotation – how is
movement controlled?
.Femoropatellar joint
- Gliding joint
From week 3 lecture
Forelimb (Thoracic limb) Joints
Forelimb (Thoracic limb) joints
.Shoulder Joint
.Elbow Joint
.Carpus
.MCP Joint
.PIP Joint
.DIP Joint
From week 3 lecture
Hindlimb (Pelvic Limb) joints
Hindlimb (Pelvic Limb) joints
.Hip Joint
.Stifle Joint
.Hock Joint
.MTP Joint
.PIP Joint
.DIP Joint
From week 3 lecture
Scapulohumeral joint
Scapulohumeral joint
.Ball and socket/spheroid
.All directions, but in the horse mainly
flexion and extension with some adduction and abduction
From week 3 Joint names, type and function pdf
Humeroradial joint
Humeroradial joint
Hinge joint
Flexion and extension
From week 3 Joint names, type and function pdf
Carpometacarpal joint
Carpometacarpal joint
Composite plane joint
Very little movement
From week 3 Joint names, type and function pdf
