Muscle 2-respiratory and everything in between Flashcards
isometric contraction
no shortening, muscle tension increased but does not exceed load
isotonic contraction
muscle shortens because muscle tension exceeds load
Motor unit
Consists of the motor neuron and all muscle fibres (four to several hundred) it supplies
Muscle twitch
Simplest contraction resulting from a muscle fiver’s response to a single action potential from motor neuron`
Latent period
events of excitation-contraction coupling
Period of contraction
cross bridge formation, tension increases
Period of relaxation
Ca2+ re entry into SR, tension declines to zero
Concentric contractions
muscle shortens and does work EX: bicep contracts to pick up a book
Eccentric contractions
muscle lengthens and generates force EX: when laying a book down causes biceps to lengthen while generating a force
Three mechanisms that ATP is regenerated by
- direct phosphorylation of ADP by creatine phosphate (CP)
- Anaerobic pathway: glycolysis and lactate formation
- Aerobic respiration
Creatine Phosphate
is a unique molecule located in muscle fibres that donates a phosphate to ADP to instantly form ATP
Slow oxidative characteristics
- Speed of contraction is low,
- Myosin ATPase activity is slow,
- Primary pathway for ATP is aerobic,
- Myoglobin content is high,
- Fiber diametre is small
- Many Mitochondria
- Many capillaries
- Color is red
Fast oxidative characteristics
-Speed of contraction is fast
-myosin ATPase activity is fast
-Primary pathway for ATP is aerobic
-Myoglobin content is high
-Glycogen stores is intermediate
-Fiber diametre is large
-Many mitochondria
-many capillaries
Color is red to pink
Fast glycolysis characteristics
- speed of contraction is fast
- Myosin ATPase activity is fast
- Primary pathway for ATP synthesis anaerobic glycolysis
- Myoglobin content is low
- Glycogen content is high
- fiber diametre is intermediate
- few mitochondria
- few capillaries
- color is white
Describe primary differences between skeletal and cardiac muscles
- Structure
- Gap junctions
- Contracts as unit
- T tubules
- Sarcoplasmic reticulum
Skeletal muscle characteristics
- structure is long striated, cylindrical, multinucleate
- no gap junctions
- no contraction as a unit
- T tubules are abundant
- sarcoplasmic reticulum is elaborate
Cardiac muscle
- structure is long striated, branched, one or two nuclei per cell
- there is a gap junction between cells
- There is a contraction as a unit
- T tubules are wider and there are less of them
- sarcoplasmic reticulum is less elaborate
Bohr effect
downright shift of the O2 dissociation curve. as a consequence of decreased Ph increased body temp and O2 this downright shift of association curve will increase oxygen to working muscles which can be described as an increase in arteriole venus oxidation difference
Hamburger effect
also called chloride shift, is a process which occurs in the cardiovascular system and refers to the exchange of bicarbonate (HCO3) and chloride (CI) across red blood cell membranes
Four factors that muscle contraction is affected by
- Number of muscle fibers stimulated (recruitment)
- Relative size of fibers
- Frequency of stimulation
- degree of muscle stretch
Force velocity relationship
linear but negative relation between force and velocity, there is an inverted U relationship between resistance and power, peak power output corresponds to force and velocity
VO2 max
the maximum rate that oxygen can be taken up from the ambient air and transported to and used by cells for cellular respiration during physical activity
Functions of the blood
- Transport
- Regulation
- Protection
Transport
Delivering O2
Regulation
maintaining body temperature
Protection
Preventing blood loss
Erythrocytes
RBC’s, small diameter(7.5 um) cells that contribute to gas transport; have a biconcave disc shape; filled with hemoglobin for gas transport
Leukocytes
WBC’s
Blood plasma
about 90% water,
Causes of hypoxia
- decreased RBC numbers due t hemorrhage or increased destruction
- Insufficient hemoglobin per RBC(ex: iron deficiency)
- Reduced availability of O2(ex: high altitudes or lung problems)
Spectrin
is a protein that will flexibility to RBC’s
Right atrium
receives blood returning from systemic circuit
Left atrium
Receives blood returning from pulmonary circuit
Right ventricle
pumps blood through pulmonary circuit
Left ventricle
Pumps blood through systemic circuit
Atrioventricular valves
located between atria and ventricles
Semilunar valves
located between ventricles and major arteries
Tricuspid valve
(right AV valve): lies between right atria and ventricle
Mitral valve
(left AV valve, bicuspid valve): lies between left atria and ventricle
Pulmonary semilunar valve
located between
right ventricle and pulmonary trunk
Aortic semilunar valve
located between left ventricle and aorta
Coronary blood supply
functional blood supply to the heart muscle itself; shortest circulation in the body
Cardiac muscle
one central nucleus (at most 2); contains large mitochondria (25-35% of cell volume) that afford resistance to fatigue; in comparison, mitochondria represent 2% of skeletal muscle
Intercalated discs
are connecting junctions between cardiac cells that contain
Similarities between cardiac and skeletal muscle
contraction is preceded by depolarizing action potential; depolarization wave travels down T tubules; causes sarcoplasmic reticulum (SR) to contract
Systemic circuit
Goes throughout the body, long high pressure circulation, receives oxygenated blood from left ventricle, blood gets pumped to tissues, then pumps deoxygenated blood into the right atrium
Pulmonary circultion
short low pressure that only pumps to the lungs to get rid of CO2, receives deoxygenated blood from right ventricle, pumps oxygenated blood into left atrium
Receiving chambers of the heart
right atrium and left atrium
pumping chambers of the heart
right ventricle and left ventricle
Atria
three veins empty into right atrium: superior vena cava, inferior vena cava, coronary sinus
Sinoatrial node
SA node, pacemaker in right atrial wall, about 75x/minute (sinus rhythm)
Atrioventricular node
AV node, delays impulses approximately 0.1 second- because fibers are smaller in diameter, have fewer gap junctions; inherent rate of 50x/minute in absence of SA node input
AV bundle
only electrical connection between atria and ventricles-right and left bundle
Right and left bundle branches: carry impulses toward apex of heart
Systole
period of heart contraction
Diastole
heart relaxation
End diastolic volume
volume of blood in each ventricle at the end of ventricular diastole
End systolic volume
volume of blood remaining in each ventricle after systole
Cardiac cycle
blood flow through heart during one complete heartbeat
Why do we care about VO2 max?
Because it’s a good indicator of your cardiovascular health, the higher the Vo2 max the higher the ATP and longevity
Cardiac output equation
Heart rate (HR) x stroke volume
Cardiac output
amount of blood pumped out of each ventricle in 1 minute
Three factors of heart rate
autonomic nervous system, chemicals, other factors
Branches of autonomic nervous system
parasympathetic and sympathetic
Parasympathetic
conserves energy as it slows the heart rate
Sympathetic
regulates the bodys unconscious actions
How can we improve Venus return
By doing physical activity
Stroke Volume influencers
preload, contractility, Afterload
Preload
degree to which cardiac muscle cells are stretched just before they contract, most important part of pre load is venous return
Venous return
amount of blood returning to the heart
Contractility
Contractile strength at given muscle length
After load
back pressure exerted by arterial blood
More factors of heart rate
age, gender, exercise, body temp
Blood vessels
delivery system of dynamic structures that begins and ends at heart
Arteries
carry blood away from heart;
Capillaries
direct contact with tissue cells; directly serve cellular needs
Veins
carry blood toward heart
Positive inotropic agents
increase contractility
Negative inotropic agents
acidosis (excess H+) increased extracellular K+, calcium channel blockers
The three layer walls of vessels
- Tunica Intima
- Tunica media
- Tunica externa
Three groups of arteries
- elastic arteries
- muscular arteries
- arterioles
elastic arteries
Thick-walled with large low-resistance lumen
Arterioles
smallest of all arteries
Microscopic vessels
diameters so small only single RBS can pass through at a time
blood flow
volume of blood flowing through vessel, organ, or entire circulation in given period
blood pressure
force per unit area exerted on wall of blood vessel by blood
resistance
opposition to flow
Three important sources of resistance
Blood viscosity
Total blood vessel length
Blood vessel diameter
Arterial blood pressure is determined by two factors
elasticity of arteries close to heart
volume of blood forced into them
Systolic pressure
pressure exerted in aorta during ventricular contraction
Diastolic pressure
Lowest level of aortic pressure
Pulse pressure
Difference between systolic and diastolic pressure
Mean arterial pressure (MAP)
pressure that propels blood to tissues
Factors aiding venous return
muscular pump
respiratory pump
sympathetic venoconstricition
Inspiration
gasses flow into lungs
Expiration
gasses exit lungs
spirometer
original, cumbersome clinical tool used to measure patient’s respiratory volumes
anatomical dead space
does not contribute to gas exchange
alveolar dead space
space occupied by non functional alveoli
total dead space
sum of anatomical and alveolar dead space
