The Heart Flashcards
(35 cards)
What are the 4 main functions of the CV system?
- Transport o2, nutrients, and metabolites to tissue
- Remove waste
- Distribute and secrete hormones
- Involvement in Homeostatic mechanisms
Equation for resistance?
1/r^4
Equation for flow?
Pressure difference / Resistance
How is flow created and what is this called?
Pressure difference between two points = Driving pressure
How is flow created in the heart?
Ventricular contractions causes a pressure difference between chambers, this pressure is passed into the blood causing it to flow along the blood vessels down a pressure gradient
Equation for velocity of flow?
Flow rate/Cross sectional area
What are the key landmarks in the Thoracic Cavity?(6)
Thyroid gland
Lung
Trachea
First rib
Diaphragm
Apex of the Heart
What is the heart surrounded by? And what is its structure?
A fibrous sac called the Pericardium
What are the 2 roles of the Pericardium?
- Protects the heart by providing lubrication to allow constant movement
- Anchors the heart against the diaphragm and spine
What are the valves of the heart?(5)
Pulmonary valves
Aortic Valves
Coronary arteries
Tricuspid valve
Mitral valve
What are the key landmarks in the heart?(9)
Vena cava
Inferior vena cava
Right atrium
Right ventricle
Pulmonary arteries
Pulmonary veins
Left atrium
Left ventricle
Aorta
Compare the properties of cardiac muscle and skeletal muscle? (Muscle fibres, Action, Sarcoplasmic reticulum, Nuclei, Source of Ca2+, Metabolism and energy)
Both have striated fibres
Cardiac is involuntary using the ANS
Cardiac has a less and smaller SR
Cardiac has a single nucleus per cell and centrally located compared to multiple and peripherally
Cardiac has SR and Ca2+ entry Skeletal only has SR
Cardiac is highly oxidative compared to oxidative and glycolytic
What is the excitation-contraction process in cardiac muscles?
- Sodium enters the intracellular fluid
- Calcium also enters via the L type Ca2+ channel
- This triggers more Ca2+ to enter from the Sarcoplasmic reticulum through Ryanodine receptor channels
- Thin filament are activatied
- Cross bridge cycling, force generation, and filament sliding theory
- Ca2+ ATPase pump - ADP > ATP
- Potassium leaves and enters T-tubule lumen
Where is smooth muscle located?
In organs
Structure/Properties of smooth muscle?
No sarcomere, the actin an myosin filaments are arranged in a lattice around a cell
They attach to cells via specialised areas - dense oldies
Mechanically connected to neighbouring bodies by dense bands
What is the anatomy of arteries?
Adventitia
Elastin
Endothelium
Smooth muscle
Pre capillary sphincters
Function of arterioles?
Altering levels of resistance to blood flow in order to distribute the available amount of blood to where it is needed
Capillary adaptations?
Large SA
Thin = quick diffusion
Spread across the whole body
Veins compared to arteries?
Larger
Valves
Less elastic
Thinner
Less smooth muscle
Definition for Cardiac Output?
Volume of blood pumped out of the heart every minute
Equation for Cardiac Output?
Heart rate x Stroke volume
Typical values for Q, HR, SV? (Untrained rest, Untrained , Trained and Elite - during exercise)
Q - 5.6, 20, 23, 30
HR - 70, 192, 190, 178
SV - 80, 105, 120, 170
How is HR decreased?
Decrease = Parasympathetic nerve endings - vagus nerves secrete acetylcholine
= SA node stimulation
= Membrane becomes more hyperpolarised
= depolarising drift is slower
= slower rhythm
= HR decreases
How is HR Increased?
Increase = Sympathetic fibres - Cardiac nerves release norepinephrine, alongside circulating epinephrine
= SA node stimulated
= membrane to become more polarised
= depolarising drift is faster
= faster rhythm
= Increase HR
