Muscles + Cardiovascular System Flashcards
In skeletal muscle, What does epimysium surround?
Muscles
What are extrinsic muscles?
Muscles that are attached to bone/cartilage
In skeletal muscle, What is a fascicle?
A group of muscle fibres
What are the 3 muscle types?
Skeletal, cardiac and smooth
In skeletal muscle, What is the endomysium made of?
Connective tissue
In skeletal muscle, What does the endomysium surround?
Muscle fibres
What are intrinsic muscles?
Muscles that aren’t attached to bone or cartilage, instead attached to something else (ie other muscles)
In skeletal muscle, What surrounds a fascicle?
Perimysium
In skeletal muscle, what is a muscle fibre surrounded by?
Endomysium
In skeletal muscle, What do you call a group of muscle fibres?
Fascicle
In skeletal muscle, What is perimysium?
Connective tissue carrying nerves and blood
What are the 3 types of skeletal muscle? (What are their sizes?)
Red (narrow), intermediate and white (wide)
What are the bands within skeletal muscle?
M band
H band
A band
(Remember: My Hands are Amazing)
Z band
I band
In skeletal muscle, What does perimysium surround?
Fascicles
In skeletal muscle, What do many fascicles make up?
Muscle
What does calcium bind to in skeletal muscles?
Troponin
In skeletal muscle, What surrounds a muscle?
Epimysium
What are the thick filaments in skeletal muscle called?
Myosin
What are the thin filaments in skeletal muscle called?
Actin
What are the cells like that make up skeletal muscle fibres?
Multinucleated peripheral cells
What is atrophy?
The wasting of muscles, when destruction>replacement
What is hypertrophy?
The growth of muscles, destruction
What are the 3 types of atrophy? Give brief descriptions of the types
Disuse- due to prolonged bedrest/sedentary lifestyle, loss of protein occurs
Muscle- occurs naturally with age (affects temp regulation)
Denervation- when neurones are severed meaning muscles stop working
What happens to the muscle during hypertrophy?
The muscle fibres increase in diameter
Metabolic changes occur: more enzyme activity for glycolysis, More mitochondria, more stored glycogen, more blood flow
What increases in number when you stretch your muscles?
Sarcomeres
What decreases in number when you immobilise a muscle
Sarcomeres
What does having more sarcomeres mean?
Long muscles
What does have few sarcomeres mean?
Reduced muscle length
What system do NPs act to counter?
Renin-angiotensin-aldosterone system
What does Ca2+ binding in skeletal muscle cause and how?
Ca2+ binds to troponin which causes tropomyosin to move, allowing the myosin filaments to attach to the actin filaments creating cross bridges and causing a contraction
What is the role of ATP in muscle contraction?
ATP binds to myosin head
Hydrolysed to give ADP+Pi
This causes myosin head to form a cross bridge with the actin filament
Power stroke triggered, ADP and Pi are released during the power stroke
Myosin head remains attached to actin filament though
Only released when a new molecule of ATP binds to myosin
It is the hydrolyses of this ATP that would result in another power stroke
When would troponin be released?
If muscle is ischaemic
What could you do to assess the level of ischaemia within a body?
Troponin assay
Where do you find Creatine Kinase (CK)?
In metabolically active tissues
What can CK be used to indicate?
Myocardial infarctions (and size of) General skeletal muscle/brain tissue damage
What two types of muscle types are striated?
skeletal and cardiac
How many nuclei do cardiac muscle cells have? Where are they located?
Single (mostly)
In the centre
How many nuclei do skeletal muscle fibres have? Where are they located?
Multinucleated
Peripheral
How many nuclei do smooth muscle fibres have? Where are they located?
Single
Central
What are the defining features of cardiac muscle?
Intercalated discs (which effectively replace the intercalated discs)
Branching
No myofibrils (things that make up muscle fibre)
Diad
What part of the troponin does Ca2+ bind to?
TnC subunit
What does hyperplasia mean in terms of muscles?
There is a multiplication in the number of cells
What are released when there is atrial/ventricular distension?
Natriuretic peptides
When are natriuretic peptides released?
When there is atrial/ventricular distension
What do Natriuretic peptides do?
Reduce arterial BP by reducing blood volume and systemic vascular resistance
Done by the kidneys allowing the loss of more water and Na+
What does the tunica intima consist off?
Endothelium
Subendothelial
Lamina propria
In what cells are ANPs made, stored and released by?
Atrial myocytes
Where is BNP synthesised?
Brain and ventricles
What are the 2 main types of BNP?
BNP (32 aa’s long) and NT-pro-BNP (76 aa’s long)
NT=n terminal
What are purkinje fibres?
Specialised myocardial cells, that conduct/transmit action potentials from AVN to ventricles
What makes purkinje fibres different from normal myocardiac cells? (4)
Bigger
More glycogen
Sparse filaments
Extensive gap junction (allow fast conduction)
What are the 2 types of natriuretic peptides?
Atrial Natriuretic peptides (ANP)
Brain-type Natriuretic peptides (BNP)
What are the defining features of smooth muscle? (3)
Non-striated,
No sarcomeres,
No tubules
Despite being neither striated nor having sarcomeres, what do smooth muscles still have?
Actin-myosin interactions
How do smooth muscle contractions differ from that of skeletal or cardiac muscle contractions?
Slower,
More sustainable
Require less ATP
What does smooth muscle form?
Sheets/bundles/layers
What are two specialised smooth muscle cells?
Myoepithelial cells and myofibroblasts
What do myoepithelial cells do?
Form basket Work around exocrine glands and contract to assist with secretion (ie moving milk, saliva, sweat into ducts).
What do myofibroblasts do?
Present at wound healing sites, produce collagenous matrix and can contact to close wound
How are the myosin and action filaments arranged in a smooth muscle cell?
Diagonally so cell contracts in a twisting way
What are the regeneration capabilities of all 3 muscle types?
Skeletal- little regeneration (mitotic activity of satellite cells)
Cardiac- no regeneration (fibroblast lay down scar tissue)
Smooth- good regeneration (cells retain mitotic activity)
What does the Frank-Starling curve show?
The larger the volume entering the ventricles, the greater the force of contraction
What is the stroke volume?
Volume of blood ejected by the L. Ventricle in a single contraction
What is the ventricular end diastolic volume?
Vol of blood in ventricle just before a contraction
What does the Frank starling curve illustrate about sarcomere length?
That if the sarcomeres are stretched to wide (due to too large a ventricular end diastole volume) then stroke volume decreases because contractions cant occur
What is the name of the valve that separates the right atrium from the right ventricle?
Tricuspid valve
What gets thicker as veins get larger?
The tunica intima
What is the name of the valve that separates the right ventricle from the pulmonary artery?
Pulmonary valve (semilunar)
What is the name of the valve that separates the left atrium from the left ventricle?
Mitral valve
What is the name of the valve that separates the left ventricle from the aorta?
Aortic valve (semilunar)
What are symptoms of left heart failure? (3)
Tachycardia, fatigue, pulmonary congestion
What are the symptoms of right heart failure? (2)
Ascites, dependent oedema
How can someone with left heart failure get pulmonary oedema?
Backing up of blood, increases hydrostatic pressure, fluid moves out of blood into alveoli
What can be measured in blood/urine that might result from dead muscle in the leg? (3)
CK levels
Protein levels (proteins only found in muscles may be circulating)
pH levels- if lactate is released
What is the distribution of blood around the heart + lungs, arteries, veins and capillaries? (Give in order of most blood to least blood)
Veins (65%)
Heart+lungs (20%)
Arteries (10%)
Capillaries (5%)
Where is smooth muscle located on metarterioles?
The point at which capillaries branch off (function as sphincters)
What does the tunica media consist of?
Smooth muscles
What is an end artery?
Terminal artery supplying all or most of the blood to a body part, without significant collateral circulation
Name functional end arteries (4)
Coronary
Splenic
Cerebral
Renal
Why are post capillary venules more permeable to water than capillaries?
To encourage fluid reuptake
Name absolute end arteries (1)
Central retina supplying artery
List in order the 10 vessels/organs that the blood travels through
Heart Large arteries Medium arteries Arterioles Metarterioles Capillaries Post capillary venules Venules Medium veins Large veins
What is the path that electrical signals in the heart take?
SAN, AVN, Bundle of His, bundle branches, purkinje fibres
What is capacitance?
The ability of a vessel to hold large amounts of blood without increasing the blood pressure
(Veins are capacitance vessels because they have thin non-elastic walls)
Name the 3 arteries that stem from the arch of aorta
Common carotid
Subclavian
Brachiocephalic trunk (which separates into the other arteries)
What are the layers of the arteries?
Tunica intima (endothelial) Tunica media (smooth muscles cells and elastic tissue) Tunica externa (connective tissue)
What is an aneurysm?
Excessive localised enlargement of an artery (caused by weakness in the arterial wall)
What is the basic structure of veins?
Tunica intima
Tunica media
Tunica externa
What does the tunica externa consist of?
Connective tissue
What are pericytes?
Cells that form branching networks around capillaries and can differentiate into muscle cells or fibroblasts
