Worksheet 2 + Quiz 2

As a cow is advancing its thoracic limb forward the brachiocephalicus m. attached at the humerus is known as the point of _____________.

insertion

Inflammation of the supraspinous bursa in horses is commonly known as?

fistulous withers

This muscle is a very strong adductor of the shoulder ___________.

pectoral m.

This muscle is an extensor of the hip ___________.

 semitendinosus m.

Within the spinal cord sensory neurons project through the _____________.

dorsal root

A postganlionic fiber (neuron) of the sympathetic system will release what neurotransmitter?

norepinephrine

Where all of the ganglion come together in the thoracolumbar division of the nervous system?

sympathetic trunk

Autonomic NS controls:

smooth & cardiac muscles

Somatic NS controls:

skeletal muscles

A

patella

B

femur

C

lateral collateral ligament

D

caudal cruiate ligament

E

cranial cruciate ligament

F

medial meniscus

G

Medial collateral ligament

H

fibula

Atlanta bursa =

evil pon

vagus =

cranial nerve

Glutamine =

excitatory neurotransmitter

y-amino buturic acid =

most prevalent inhibitor

Synergists = 

• assist another muscle in performing a movement

• Brachiocephalicus

• Biceps brachii

• Brachialis

• Triceps brachii

• Semitendinosus

• Biceps femoris

• Grastrocnemius

• Supraspinatus

Agonists =

• the muscles that are primarily responsible for producing a specific movement at a joint

• biceps brachii

• brachialis

Antagonists = 

• muscles that oppose or reverse a movement

• biceps brachii

• triceps brachii

Brachiocephalicus = 

• attached to cervical vertibrae + skull cranially & humerus caudally

• extensor of shoulder

Biceps brachii =

• cranial side of the limb

• extends from scapula to radius 

• flexor of elbow

Brachialis =

• distal to the bicep muscle of the forearm

• flexor of elbow

Triceps brachii =

• caudal side of the limb

• extensors of the elbow

Semitendinosus

• superficial

• in hindquarters

• extensor of hip

• flexor of stifle

Biceps femoris =

• makes up the hamstrings

• extensor of hip

Grastrocnemius =

• caudal surface of femur

• extensor of hock

• flexor of stifle

Supraspinatus =

• in the shoulder

• extensor of shoulder

Infraspinatus =

• lateral collateral ligament of the shoulder joint

• flexor of shoulder

Deltoideus

• superficial shoulder muscle

• flexor of shoulder 

Middle Gluteal =

• glutes

• extensor of hip

Quadraceps = 

• on the front of the femur

• extensor of stifle

Iliacus =

• pelvic region

• flexor of hip 

Strong adductor of shoulder =

pectoral

Abductor of hip =

superficial gluteal

Abductor of shoulder =

infraspinatus

Parallel Fibers =

• entire length of muscle

• fast/extension movement

• speed

• greatest potential for shortening, but weak

Both Parallel and Pennate Fibers =

fundamental muscle contraction

Pennate Fibers =

• muscles axis of force transmission

• large forces/heavy moving

• force

• increased power but less potential for shortening

What is aponeuroses?

• a flattened, connective tissue, that helps connect muscle to bones

• pearly white fibrous tissue similar to tendon

Origin = 

more stable attachment site

Insertion = 

more mobile end

Brachiocephalicus — Advance thoracic limb when foot is off ground:

• Origin = C1

• insertion = humerus 

Brachiocephalicus — flex neck to the side if foot is bearing weight:

• origin = humerus

• insertion = C1

1) Action potential arrival

a nerve impulse arrives at the axon terminal of the motor neuron at the neuromuscular junction

2) Acetylcholine release

the action potential triggers the opening of voltage-gated calcium channels, allowing calcium ions to enter the axon terminal, thus releasing Ach

3) Ach Binding

ach binds to nicotinic receptors on the muscle fibers sarcolemma, causing ion channels to open, allowing sodium ions to enter and potassium to leave

How many Na in and K out?

3 Na+ in

2 K+ out

4) Action Potential Muscle Fiber

the depolarization spreads along the sarcolemma, leading to the generation of an action potential in the muscle fiber

5) T-tubule

the action potential travels along the sarcolemma and down into the t-tubules, which penetrate the muscle cell

6) Calcium Release

the action potential in the t-tubules triggers voltage sensitive receptors on the sarcoplasmic reticulum, causing calcium ions to be released from the SR into cystol

7) Muscle Contraction

the released calcium binds to troponin, causing conformational change in tropomyosin, exposing the active sites on actin filaments, allowing cross bridge formation with myosin heads - resulting in contraction 

Myosin =

1500 thick myofilaments

Actin =

3000 thin myofilaments

1) Calcium binds to

C troponin

2) Conformational

change of troponin

3) Tropomyosin shifts

uncovering myosin binding sites

4) Cross bridge formation

as myosin heads attach to actin

5) power stroke occurs

as myosin heads pivot and pull actin filaments towards the center of the sarcomere, resulting in muscle contraction

6) ATP binding

to myosin head (allowing it to reattach to a new position) causing myosin to detach from actin

7) ATP is

hydrolyzed into ADP and P, which re-energize myosin head

8) Repeat

cycle for muscle contractions 

Smooth 1

stimulus causes calcium ions to enter smooth muscle cell

Smooth 2

calcium then binds to protein calmodulin, forming a calcium calmodulin complex

Smooth 3

the calcium-calmodulin complex activates enzyme myosin light chain kinase

Smooth 4

activated MLCK phosphorolates the MLC in the myosin head, which enables myosin to interact with actin

Smooth 5

phosphorolated myosin forms cross bridges with actin filaments, allowing the sliding of actin and myosin to pass each other

Smooth 6

sliding of actin and myosin shortens the smooth musclecell, causing contraction

Smooth 7

relaxation

Describe the roles of the autonomic nervous system in causing contraction

• ANS regulates smooth muscle contractions based on the body’s needs with the sympathetic nervous system and the parasympathetic NS

• ANS can trigger different contractions in blood vessels or digestive tract

Describe the roles of the autonomic nervous system in causing relaxation

• ANS ensures smooth muscle relaxation is balanced with contraction

• ANS can relax various tissues for blood flow regulation and gastrointestinal motility

Draw and label the preglanglionic and postglanglionic fibers of the parasympathetic and sympathetic nervous system. Label the neurotransmitter released and the receptor which binds said neurotransmitter.

do on paper

Ion channels associated with generating an action potential at the plasma membrane of the axon:

• Na+/K+ pump

• Voltage gated Na+ channels

• Action Potential

• Hyperpolarization

• Return to resting potential

Na+/K+ pump

maintain the resting membrane potential of -70mv

Voltage gated Na+ channels

these open, allowing Na+ influx and rapidly increasing membrane potential

Action Potential

voltage gated Na+ channels inactivate and K+ channels open — allowing K+ efflux, returning the membrane potential to negative

Hyperpolarization

K+ channels remain open longer than needed, causing overshoot of negative charge

Return of Resting Potential

K+ channels close, and the Na+/K+ pump restores the original ion concentration

Once this action potentials reaches the nerve terminus (end plate) describe the series of events leading to release of a neurotransmitter.

The release of neurotransmitters involves the arrival of an action potential, opening of voltage gated Ca2+ channels, influx of Ca+ ions, fusion of synaptic vesicles with the membrane + endocytosis of neurontransmitters into the synaptic cleft, leading to communication with the postsynaptic neuron.

How to remove neurotransmitter:

• enzyme degrades it

• cell membrane absorbs it

• neurotransmitter diffuses away 

Draw the diagrams drawn in class

on paper

Draw the nervous system flowchart

on paper