MSK System Physiology 1 Flashcards
What are the 3 types of cartilage?
Hyaline
Elastic
Fibrous
What are the 3 types of muscle?
Skeletal
Cardiac
Smooth
What distinguishes hyaluronic acid form other glycosaminoglycans?
It has no sulphate bonds and is not protein-linked
Which glycosaminoglycan is the most abundant?
Chondroitin sulphate
What is the contractile unit of muscle?
The sarcomere
What is the name of the organelle in the muscle cell that is high in calcium?
Sarcoplasmic reticulum
What is the neurotransmitter of the neuromuscular junction?
Acetylcholine
What substance fluxes through open gated channels when the action potential reaches the terminal bouton?
Calcium
The depolarization of the post synaptic membrane is known as what?
The End Plate Potential (epp)
Why will the epp always reach threshold every time?
Because it is suprathreshold
What stops the action of acetylcholine in the synaptic cleft?
Acetyl choline esterase. AChE breaks down Ach into choline and acetate.
Adrenergic synapses use what neurotransmitter?
Norepinephrine
What are the 2 contractile proteins of muscle?
Actin and myosin
Which of the contractile proteins is found in the thin filament?
Actin
Which of the contractile proteins is found in the thick filament?
Myosin
What are the 2 regulatory proteins that are also found on the thin filament?
Troponin and tropomyosin
Which is the regulatory protein that has an inhibitory action on the formation of actin-myosin complex?
Tropomyosin
What substance causes the troponin-tropomyosin complex to fall away from the active site of the actin molecule?
Calcium
To which of the regulatory proteins does calcium bind?
Troponin
What substance is bound to the myosin head?
atp
What two things do we need to get the muscle to relax?
(1) Removal of calcium
(2) Formation of atop on myosin head
Lifting and setting down contraction with muscle shortening and lengthening is known as what type of contraction?
Isotonic
Contraction with no external muscle shortening is what type of muscle contraction?
Isometric
The force-velocity curve describes what type of muscle contraction?
Isotonic (velocity gives sense of movement)
The length-tension curve describes what type of muscle contraction?
Isometric
Posture, heat generation, nerve nutrition of muscle and general circulation are all functions of what?
Muscle tone
What is it called when a series of action potentials reach a muscle such that it cannot relax and so force within a muscle is built to a maximum?
Summation of twitches
Accumulation of calcium in the cytoplasm is the mechanism for what?
Summation of twitches
What are the 3 muscle fiber types?
Fast oxidative glycolytic
Slow oxidative
Fast glycolytic
Marathon runners have more of what muscle fibers?
Slow oxidative
Sprinters have more of what type of muscle fibers?
Fast glycolytic
Where do you find smooth muscle in the body?
Hollow organs, blood vessels, lymphatics, in the skin to do piloerection and in the eye
What are the 2 different types of smooth muscle?
(1) Multi unit
(2) Visceral-contracts as a single unit
Piloerection and the ciliary muscles of the eyes are examples of what type of smooth muscle?
Multi unit
Gap junctions are found in which type of smooth muscle?
Viscera
What is the cytoplasmic binding protein found in smooth muscle?
Calmodulin
What are 2 possible sources of calcium for smooth muscle contraction?
(1) Mitochondrion
(2) Intracellular vesicles
How does relaxation of smooth muscle differ from relaxation of skeletal muscle?
It requires a light chain phosphatase enzyme to remove phosphate from myosin. In skeletal muscle relaxation is based on the reuptake of calcium and atp formation on the myosin head.
What are the 2 types of action potentials in smooth muscle?
(1) Spike potential
(2) Plateau potential
The gut, blood vessels experience what type of smooth muscle action potential?
Spike
The uterus and bladder experience what type of smooth muscle action potential?
Plateau potential
Smooth muscle contraction is regulated in what 2 ways?
(1) Neurally i.e. via neurotransmitters
(2) Hormonally via blood borne agents (epi) and local tissue factors (O2, CO2, H+)
What happens to smooth muscle when it is stretched?
It will often lead to a spike potential and contraction
What happens to heart rate during an exercise bout?
It increases
What does the increase in heart rate during an exercise bout do to stroke volume?
Increases it
What happens to renal and splanchnic blood flow during an exercise bout?
They decrease
After the anaerobic threshold is reached during an exercise bout what causes an increase in ventilation?
Increased lactic acid. Carotid bodies are responsible for this detection.
What is the only metabolic hormone to be decreased in an exercise bout?
Insulin. Insulin encourages glucose reuptake of the cells.
What happens in skeletal muscle during an exercise bout?
- Increase in blood flow because vascular beds dilate and receive extra blood from renal and splanchnic beds
- Increased metabolism up to 25X
- Increased oxygen extraction
How does maximum heart rate get affected by training?
It remains unchanged
What happens to submax heart rate in a trained heart?
It decreases
What happens to the coronaries in a trained heart?
They increase in size, not in number
How is stroke volume affected in a trained athlete?
It will increase because the heart is more efficient and better able to handle demands
How is oxygen consumption affected in a trained athlete?
It will decrease
What happens to mitochondrion content in a trained athletes skeletal muscle?
They increase
What happens to capillary density in a trained athletes skeletal muscle?
It increases
What happens to protein content of skeletal muscle with resistive training?
It will increase
What happens to lactate production in a trained athlete?
Less is produced for the same workload
Glucose and glycogen are spared due to the increased metabolism of what?
Fatty acids
What type of exercise will increase bone mass?
Weight bearing exercise
What kind of exercise will increase size and strength of ligaments and tendons?
Resistance training
How is insulin affected during rest and an exercise bout in a trained athlete?
Rest: lower insulin levels with higher sensitivity of receptors
Exercise bout: higher insulin levels with lower sensitivity of receptors
What happens to epi, norepi, cortisol, glucagon and GH during an exercise bout in a trained athlete?
They experience a lower rise
