Exam 3 Flashcards
What are the characteristics of muscle tissue
Excitability, contractibility, extensibility, and elasticity
What are the primary functions of muscle
Provide motion, maintain posture, and generate heat
What happens to skeletal muscle when damaged
It is repaired or replaced by connective tissue new skeletal muscle fibers are not formed
What happens to skeletal muscle if the nerve supply to the muscle is destroyed
The muscle atrophies
What is a fascicle
A bundle of muscle fibers
What is the endomysium
A connective sheath that covers each muscle fiber
What is the perimysium
Connective sheath that covers a fascicle
What is the epimysium
Connective sheath that covers the entire muscle
What is the fascia
Binds muscles to each other and keeps them in position and separates them
What is the deep fascia
Surrounds a group of muscles and goes in btw the ind muscles
What is superficial fascia
Loosely connected to muscle and is usually next to the skin
What is the belly of the muscle
The thickest part of the muscle
What is a digastric muscle
If the muscle is divided by an intermediate tendon so that it actually has 2 bellies
What are the skeletal muscle attachments comprised of
Tendons and aponeuroses are formed from continuations of the epimysium, perimysium, and endomysium
What is aponeuroses
Attached to bones or muscles by broad sheets of fibrous tissue
What is the origin of a skeletal muscle
The more stable attachment site that does not move much when the muscle contracts
What is the insertion site for skeletal muscles
Site that undergoes the most movement when a muscle contracts
What is a agonist skeletal muscle
The prime mover that directly produces a desired movement
What is an antagonist skeletal muscle
Directly opposes the action of an agonist
What is the synergist skeletal muscle
Contracts at same time as agonist to assist its action such as the deep and superficial digital flexor muscles
What are fixator skeletal muscles
Stabilizes joints to allow other movements such as digital flexors + extensors allowing flexion of digits w/o flexing wrist
What is a synergistic action
Muscles working together to produce smooth and controlled movement indirectly aiding the action of the prime mover
What is rotation
The movement of a part around its long axis
What is circumduction
The movement of an extremity that describes the surface of a cone
What is supination
Movement of the forearm so the palmar side is rotated upward or forward
What is pronation
The movement of the palmar side of the paw or foot downward or backward
What are the characteristics that goes into the name of a skeletal muscle
Action, shape, location, direction of fibers, number of heads, and attachment sites
What is the function of the masseter muscle and where is it located
It enables mastication and is located on the side of the cheeks
What muscles are responsible for raising the head and neck
The splenius and trapezius
Where is the trapezius located
It is on the dorsal aspect of the neck
Where is the splenius muscle located
It is the most cranial muscle in the middle of the neck taking up the top 3rd of the neck
What is the function and location of the brachiocephalicus muscle
It extends the head and neck and is located on the ventral aspect of the neck
What is the function of the sternocephalicus and where is it located
It flexes the head and neck and it is ventral of the brachiocephalicus
What are the functions of the abdominal skeletal muscles
Support abdominal organs, help flex the back, participate in defecation, urination, parturition, vomiting, and regurgitation increasing intraabdominal pressure, and contributes to respiration as a fail safe
What are the layers of the abdominal skeletal muscles
External abdominal oblique muscle, internal abdominal oblique muscles, rectus abdominis, and transversus abdominis
What is the linea alba
The left and right parts of the abdominal muscles that come together in the center of the abdomen
What is the function of the thoracic limb skeletal muscles
Functions mainly for locomotion
What are the adductor muscles in the thoracic limb
Latissimus dorsi (pull up) and pectoral muscles (bear hug)
What is the abductor muscle in the thoracic limb
Deltoid muscle (shoulder caps)
What are the brachial muscles
Biceps brachii and triceps brachii
What are the carpal and digital muscles
Extensor carpi radialis and deep digital flexor
Where is the latissimus dorsi muscle located
Runs along the craniodorsal part of the abdomen
Where is the deep pectoral muscle located
It is on the cranioventral aspect of the abdomen near the thoracic limb
Where is the ulnar carpal flexor and extensor muscle
On the caudal side of the thoracic limb
Where is the extensor muscles of carpus and digits
On the cranial aspect of the thoracic limb
Where are the triceps muscles located
Proximal to the extensor and ulnar muscles
Where are deltoid muscles located
Cranial to the tricep muscles near the point of the shoulder
What is the function of the pelvic limb skeletal muscles
Locomotion
What are the extensor muscles in the hip joint
Gluteal muscles and hamstring muscle group
What are the muscles in the hamstring muscle group
Biceps femoris, semimembranosus muscle, and semitendinosus muscle
Where is the biceps femoris
On the lateral caudal aspect of the proximal femur
Where is the semitendinosus muscle
Medial to the biceps femoris
Where is the semimembranosus muscle
Medial to the proximal end of the semitendinosus muscle
What are the extensor muscles of the stifle joint
The quadriceps femoris
What are the different parts of the quadriceps femoris
Rectus femoris, vastus intermedius, vastus lateralis, and vastus medialis
Where is the rectus femoris located
On the medial superficial aspect of the femur
Where is the vastus intermedius
Sits under the rectus femoris
Where is the vastus lateralis
On the lateral aspect of the rectus femoris
Where is the vastus medialis
On the medial aspect of the rectus femoris
What are the muscles in the tarsus and digits
The gastrocnemius muscle including the achilles tendon
Where is the gastrocnemius muscle
On the caudal aspect of the tibia and fibiula
What is the function of the skeletal muscles used in respiration
Increase and decrease size of thoracic cavity
What are the inspiratory muscles
Diaphragm and external intercostal muscles
What are the expiratory muscles
Internal intercostal muscles and abdominal muscles
What are the 3 respiration fail safes
The external intercostal muscles, internal intercostal muscles, and abdominal muscles
What are the red muscle fibers
Produce tonic contractions that are sustained over long periods of time but have little force and are aerobic such as slow twitch fibers
What are white fibers
Contract phasically w/ the strength of contraction building to a peak then relaxing and are anaerobic such as fast twitch fibers
What is a sarcolemma
The cell/fiber membrane of a muscle fiber that have invaginates w/in cell making T-tubules
What is the sarcoplasm
The cytoplasm of a muscle fiber
What does each fiber contain
Longitudinal myofibrils packed together like pencils
What is the sarcoplasmic reticulum
The endoplasmic reticulum in muscle fibers that store Ca there are a lot of these on myofibrils
What are myofibrils composed of
Actin and myosin
What is a sarcomere
Contractile units of muscle cells that are laid end to end w/in one myofibrils
What are Z discs
Shared end caps of sarcomeres
What are A bands
Actin + myosin filaments
What are H bands
Myosin filaments only
What are I bands
Actin filaments only
What is the Z line
Aligned z discs that are aligned w/ actin filaments
What is a motor unit
Nerve cell + axon + muscle fiber
What type of muscles are capable of precise motor action
The ones w/ many motor units/fiber
What sized muscles have fewer motor units
Large muscles
What kind of muscles have huge numbers of muscle fibers per motor unit
Large powerful moving muscles
What is the neuromuscular junction
The site where ends of motor nerve fibers connect to muscle fibers that contain the synaptic vesicles at the end of the nerve fiber containing acetylcholine
What is the physiologic process of muscle contraction
The nerve impulse comes down the motor nerve fiber once the impulse reaches the end bulb of the nerve fiber acetylcholine is released into the synaptic space and binds to receptors on the sarcolemma surface, the impulse travels along the sarcolemma and thru the T tubules to interior of the cell, and the impulse reaches the sarcoplasmic reticulum resulting in another chain of physiologic events
What physiologic process occurs after the sarcoplasmic reticulum recieves an impulse
Ca ions released into sarcoplasm, Ca diffuses into myofibrils and starts contraction, and energy is supplied by ATP
What is the physiologic process of muscle relaxation
Sarcoplasmic reticulum begins pumping Ca back in again by pulling Ca out of the myofibrils using ATP as energy, contraction stops, and the muscle returns to its original length
How are actin and myosin arranged when the muscle fibers are relaxed
They slightly overlapped
What happens w/ actin and myosin when the muscle contracts
Cross bridges ratchet back and forth, actin filaments pulled toward center of myosin filaments, and the sarcomere is shortened
What is the all or nothing principle
When stimulated ind muscle fiber contracts completely or not at all, the nervous system controls the number of muscle fibers stimulated, and increased strength results from recruiting more fibers
What is a twitch contraction
A single muscle fiber contraction that has a latent phase, contracting phase, and relaxation phase
What is the chemistry of muscle contraction
ATP provides energy by hydrolysis from myosin filament produced by mitochondria, creatine phosphate converts ADP back to ATP, catabolism of glucose and oxygen help to produce ATP and CP, glucose is stored in muscle as glycogen, and oxygen is stored as myoglobin w/in the muscle fiber
What is aerobic metabolism
Adequate oxygen supply for energy needs of muscle fiber and max energy extracted from each glucose molecule
What is anaerobic metabolism
Need for oxygen exceeds available supply forming lactic acid as a biproduct of incomplete glucose breakdown
What is muscle tone
Muscle rarely relaxes completely the fibers exhibit a persistent state of partially sustained contractions
What is muscle fatigue
During strenuous exercise and or lengthy contractions when conditions for contractility deteriorate depleting of energy stores, accumulation of wastes, and insufficient nutrition of the muscle
How do muscles produce heat
Muscle activity generates heat, mechanisms such as panting or sweating eliminate excess heat, and spasmodic muscle contractions that increase heat production such as shivering
What 3 things cause muscle fatigue
Decrease O, glucose, and creatine
At what rate do groups of cardiac cells contract
At the rate of the most rapid cell in the group
Where is the sinoatrial node located and function
Located in the wall of the right atrium it generates impulse to start each heartbeat
Why are there nerves in the cardiac muscle
To regulate the rhythm of the SA node using the sympathetic and parasympathetic systems
What are multi unit smooth muscle cells
Small discrete groups of cells that operate together for fine functions
What are the 2 types of smooth muscle cells
Visceral and multi unit
What is the organization of actin and myosin in smooth muscle cells
They are arranged as small contractile units that crisscross the cell
What are at the end of each end of smooth muscle cells
Dense bodies
What are the characteristics of visceral smooth muscle cells
Contraction is peristalsis, contracts w/o external stimulation reacting to strectching, and is affected by the sympathetic and parasympathetic
What does contraction of multunit smooth muscle cells require
Contraction requires impulses from autonomic nervous system
What are the 3 different types of blood vessels
Arteries, veins, and capillaries
What is the function of the cardiovascular system
To supply blood and drain the blood from all tissues providing O2 and nutrients along w/ removing CO2 and certain metabolites
What are arteries
Open pipes blood can be pushed in either direction through and is dependent on the pressure produced by the heart contraction
What are veins
Vessels that contain less smooth muscle in the wall, contains valves, and as undirectional flow of blood
What is base of the heart
The rounded cranial end
What is the apex of the heart
The more pointed caudal end
Where is the heart located
In mediastinum w/ the apex shifted to the left sitting more ventral
What is the mediastinum
The space btw the 2 lungs
What is the pericardium
The fibrous sac containing the heart parts include the pericardial sac and the serous pericardium
What fills the pericardial space
Pericardial fluid
What is the function of the pericardium
To prevent external friction, inflammation from surrounding structures, stabilize the heart position, and help maintain cardiac shape
What secretes the pericaridal fluid
The serous surfaces
What is pericardial effusion
Increase in the volume of fluid in the pericardium
What can cause pericardial effusion
Pericarditis, bacterial infection, FIP, cardiomyopathy, or cardiac neoplasia
How do you know if you are actually removing blood from the pericardium
It will not clot
What are symptoms that indicate pericardial effusion
Pale gums, normal hematocrit, weak pulse, and difficult to ascult heart sounds
What is the fastest way to diagnose pericardial effusion
Ultrasound
What are the 3 layers of the heart wall from deep to surficial
Endocardium, myocardium, and epicardium
What does the endocardium cover
The papillary muscles
What are the auricles
Blind pouches that come off the atria
What is the interventricular groove
Formed by interatrial septum and interventricular septum and contains coronary blood vessels and fat
What are the atria of the heart
The 2 chambers at the base of the heart separated by the interatrial septum that blood and push out to the ventricles by contracting their walls
What are the ventricles of the heart
2 chambers that sit below the atria, pumps blood out of the heart to the rest of the body, and are separated by the interventricular septum
What is the blood flow thru the cardiovascular system
Vena cava, right atrium, right ventricle, pulmonary arteries, lungs, pulmonary veins, left atrium, left ventricle, aorta, out to body, and repeat
What are the 4 one way valves
Pulmonary valve (semilunar), right atrioventricular (tricuspid valve), aortic (semilunar) valve, and left atrioventricular (mitral) valve
What is the function of the chordae tendonae
They prevent valves from opening backwards by attaching to the papillary muscle in the endocardium
What is the function of the 4 valves
To prevent backflow into the ventricles or the atrias after blood is pushed out
Where is the skeleton of the heart located
Btw the atria and ventricles comprised of 4 dense fibrous CT rings
What are the 4 primary functions of the skeleton of the heart
Separates the atria and ventricles, anchors heart valves, point of attachment for myocardium, and electrical insulation btw atria and ventricles
Why does the heart have a separate blood supply
The blood that circulates through the heart chambers does not provide a sufficient supply for the heart muscle
What does the blood supply to the heart consist of
The coronary arteries and veins
Where does the coronary artery descend from
The aorta
Where do the coronary veins drain the blood
Into the right atrium
What is the fail safe node in case something happens to the SA node
The atrioventricular node (AV)
What is the conduction flow of the heart
SA node produces electrical stimulus, transferred to the right atrium, across the internodal bundle to the AV node and the left atrium, then the AV node sends the electrical current to the right and left AV bundle branches sending the signal to the interventricular septum, and then to the lateral walls of the right and left ventricles
What is systole
Myocardium contracting
What is diastole
Myocardium relaxing and repolarizing
What do the heart sounds represent
Heart valves snapping shut
When does the lub sound occur
After atrial systole when the tricuspid and mitral valves shut
When does the dub sound occur
After ventricular systole when the pulmonary and aortic valves snap shut
When are abnormal heart sounds heard
When the 2 AV valves or 2 semilunar valves are not closing simultaneously
What 2 things commonly cause heart murmurs
Valvular insufficiency and valvular stenosis
What is valvular insufficiency
When one or more valves dont close all the way
What is valvular stenosis
Narrowing at one or more valves
What is the cardiac output
Volume of blood that is ejected out of the left ventricle over a unit of time
What are the variables of cardiac output
Stroke volume (SV) or systolic discharge and heart rate
What is the cardiac output calculation
CO = SV * HR
What is the stroke volume
Represents strength of the heartbeat by measuring how much blood its kicking out w/ each stroke
What are the 2 factors of stroke volume
Preload the volume of blood received from the atrium and the afterload the physical resistance the heart is beating against such as blood pressure
What is contractility
The strength of cardiac muscle cells that can also affect stroke volume
What is the only artery that carries deoxygenated blood
The pulmonary artery takes deoxygenated blood from the heart to the lungs
What is the largest elastic artery
The aorta
What are capillaries
Microscopic blood vessels from branching arterioles, occur in groups called capillary beds or networks to slow down and stager the blood flow for O and CO2 exchange, and are walls are one endothelial cell thick comprised of simple squamous epithelium
What are the only veins that carry oxygenated blood
The pulmonary veins that carry oxygenated blood from the lungs and to the heart
What do capillaries join together to form
Venules which join together to form veins
What are the 2 things that work together to pump blood
One way valves and skeletal muscles
What do all systemic veins drain into
Vena cava
What is the pulse
Rate of alternating stretching and recoiling of elastic fibers in an artery as blood passes through w/ each heartbeat
Where are pulses easies to palpate
Superficial arteries lying against firm surfaces
What is blood pressure
Measurement of the amount of pressure that flowing blood exerts on arterial walls is dependent upon interactions w/ HR, SV, diameter/elasticity of artery, and TBV
What is systolic blood pressure
Ejection of blood from left ventricle
What is diastolic blood pressure
Pressure remaining in artery while ventricle is filling
What is the mean arterial pressure
Average pressure during one cardiac cycle
What are the 2 methods of measuring blood pressure
Oscillometric method and doppler ultrasound
What is the oscillometric method
Cuff placed over artery and measures magnitude and frequency of pulsations
What is the doppler ultrasound
Transducer attached to sphygmomanometer and accurately measures systolic blood pressure only
What is the poor man’s dinomap
That the femoral artery can be palpated at a systolic pressure of at least 60 mmHg and the dorsal metatarsal pulse can be palpated at a systolic of at least 90 mmHg
What does lack of a femoral pulse mean
Profound hypotension
What are indirect tests to monitor cardiovascular system
Electrocardiography, echocardiography, auscultation of the thorax, arterial blood pressure evaluation, and thoracic rads
What is an electrocardiography
Based on electrical activity of the heart, detects electrical impulses on surface of animals body, and produces an electrocardiogram
What is a P wave
Time it takes depolarization to travel from SA node thru atria
What is the QRS complex
Time of ventricular depolarization
What is the T wave
Ventricular relaxation
What is an echocardiograph
Cardiac ultrasound procedure that detects the sound waves that bounce off parts of the heart as it beats and is used to evaluate the size, shape, and movement of the heart and its parts
What are the 2 methods of doing an echo
2 dimensional and doppler
What is the 2 dimensional echo
Produces 2 dimensional cross section image of the heart to see it working in real time
What does the coloration mean on a doppler echo
The color depends on if the blood is traveling towards or away from us
What is the doppler echo
Measures blood flow through the heart and adds color to the image this is useful for the evaluation of valvular stenosis and insufficiency
