week 4 Lesson 1- Cardiac Flashcards
What is the structure of the pericardium
Fibrous and tough outer layer of the heart
Double layer
Inside the layer there is fluid which prevents friction on organs when the heart beats
What is the function of the inferior Vena cava
Blood from the lower body to the heart DEOXYGENATED TO RA
What is the function of the superior Vena cava
Collects blood from upper body E.g. head to the heart DEOXYGENATED TO RA
Where does the blood go in the heart from the pulmonary veins
To the LA
what is the function of pulmonary veins
Oxygenated blood from the lungs pumped to LA , blood to move around the body
Once the blood leaves the LV where does it go
Through the AORTA then around the body
Which contains higher pressure, arteries or veins and why
Arteries. Take blood away from the heart to pump it around the body
Which side is thicker in the heart
Left
What is the function of the papillary muscles
Pull down on tendons which hold/ close valves open/closed
Where is the semi lunar valve located
Before pulmonary artery after the Right side
How many parts are in the tri and bicuspid valves
Tri-3
Bi-2
What is different from AV valves and semi lunar valves
Semi lunar valves don’t have any attachments which AV valves do- tendons with capillary muscles attached
Name all the valves and their type of valves
AV VALVES- bicuspid and tricuspid valve
SEMI LUNAR- pulmonary valve and aortic valve
What is the function of valves
To prevent the back flow of blood
Name the order of the right side of the heart
Superior vena cava
RA
tricuspid valve
RV
Pulmonary valve
Pulmonary artery
Lungs
Name the order of the left side of the heart
pulmonary veins
LA
bicuspid valve
LV
aortic valve
Aorta
Body
How does blood enter coronary arteries
Via coronary osteom (seen in aorta)
From the aorta coronary ostium, what is the blood like, how does this relate to its function
High pressure
Oxygenated
Blood can circulate around coronary arteries
At rest, how much o2 unbind from bloodu in cardiac muscle
75%
In exercise, oxygen demand can only be met by increased bloody flow and not increased extraction
How can we increase blood flow
Via vasodialation- lumen dialatea to allow more blood to flow
What increase when vasoconstriction accurs
Pressure increases
Blood flow decreases - pressure stips blood flow
Why is vasodialation good
Why is constriction sometimes bad
Allows more blood to flow so more oxygen to bind to working muscles
- reduce blood flow
How is the heart muscle different to other types of muscles
It has branching
What does branching of heart muscle allow
Interconnections between each other and the branches called INTERCOLATED DISC
What are found in the intercolated discs
Gap junctions
Desomosones
Define gap junction
Membrane bound proteins from adjacent cells line up to form a channel which allow diffusion of small ions and molecules
What does cardiac muscle have more of
Mitochondria- don’t undergo anaerobic respiration
Define desomosones. What does this allow
Act like rivets, act like a unit and stick themselves together, they don’t pull apart. Allowing contraction as one unit, all together instead of squeezing individually
What is located between muscle fibres of the cardiac muscle. What does this allow
Connective tissue skeleton
Allows to rapture itself and move things across
What is a refractory period is
Can’t be another AP generated
What is periods of relaxtation called
Diastole
What are periods of contraction called
Systole
What structure allows the spreading of electrical activity through the heart
Gap junctions
How does the structure of the cells in the heart allow spreading events to accur
Specialised myocites have unstable membrane potentials. Intrinsic control (internal) so can depolarise.
What initiates the start of the cardiac stable and why
Sinoatrial node as it’s the most u stable
What occurs after sinoatrial node starts the cycle
Atrioventricular node, bundle of his (AV bundle) this bundle branches and purkinjie fibres. (Transmits the depolarisation down)
Describe how the cardiac cycle occurs
P wave= atrial depolarisation/systole of the SA node spreads across atria causing contraction. Impulse prevented from moving into ventricles by CT skeleton/ gap junctions
QRS= ventricular depolarisation/ systole and atrial depolarisation/systole
Depolarisation of AV node spreads down to bundles of HIS, bundle branches spreading to purkinjie fibres in ventricular apex
What is the name of the structure which receives the depolarisation last in the cardiac cycle
Purkinjie fibres
what do chemoreceptors monitor
CO2 , O2, ph change (acidicity)
What do baroreceptors detect
Pressure changes ^
Where are baroreceptors found
Aortic arch
Carotid sinus
What do baroreceptors respond to
Stretch of blood vessels
What do chemoreceptors help to do
Match cardiac output to rate of ventilation
Once baroreceptors have been stretched, what occurs
Increase impulses sent to cardiovascular centre of the medulla oblongata
-CV centre has cardioscceleratory centre (accelerator) and a cardioinhibitory centre (brake)
-sympathetic outputs from cardioaccelaratory centre travels down cardiac nerve to SPEED UP
-parasympathetic outputs from cardioinhibitory centre travel down vagal nerve to SLOW DOWN
At rest what is the normal heart rate and how
60-70bpm as it’s continuously slowed (vagal tone) from 100bpm
What hormones modify the cardiac cycle
Adrenaline
Noradrenaline
Does neural control and hormonal control last longer
Neural control is quick and short lasting
Longer hours are influences from hormones to co-ordinate heart
Define stroke volume
Volume of blood leaving the heart per beat (70ml at rest)
What is cardiac output
Vol of blood leaving heart per minute
SV x HR
Name the different nodes in the heart
SA NODE
AV NODE
Describe the P wave
Atrial systole
Depolarisation of SA node spreads across atria causing contraction.
Impulse prevented from moving into ventricles by CONNECTIVE TISSUE SKELETON/ lack of gap junctions
Describe the QRS wave
Ventricular systole and atrial diastole
Depolarisation of AV node spreads to bundle of his, bundle branches and purkinjie fibres in the ventricle apex
What if the T wave
Ventricular repolarisation
Name neural control receptors and their function
Chemoreceptors- co2, o2, ph change
Baroreceptors- pressure change
What normally initiates ventricular contraction
Purkinjie fibres
How is the heart myogenic
It can beat on its own
