Anatomy of the Heart (complete) Flashcards
What are the functions of the cardiovascular system?
1) Distributes dissolved gases & nutrients
2) Removes metabolic waste
3) Control temp, O2 supply, pH, ionic composition
4) quickly adapts to changes in conditions and metabolic demands
OVERALL: to maintain homeostasis (really important)
What are the three parts of the CV system?
1) Heart
2) Blood
3) Vasculature
Describe the heart as a dual pump
Left side:
higher pressure, serves the systemic circulation
Right:
lower pressure, serves pulm circulation
No direct connection between right and left sides
Why is the right and left heart relationship described as a series?
- Because they’re not directly connected
- Output of left/right sides must be closely matched
Describe pulmonary circulation
- Low pressure
- Single pathway through a single set of capillary beds
Describe systemic circulation
- Higher pressure
- Multiple pathways from heart to systemic beds
Describe what it means when that systemic circulation is arranged in parallel
- Blood only goes to one part of the body and then goes straight back to the heart
- Changes in flow/demand in one organ does not directly affect others
- Blood flow to different organs regulated independently to match metabolic demand
What are the 4 chambers of the heart?
- L/R Atria
- L/R Ventricles
Describe the purpose of the ventricles
- Main pumpers!
- Left: supplies higher pressure systemic circulation — BIGGER & THICKER than right
- Left also does more work — uses more O2
Describe the purpose of the atria
- Small “primer” chambers
- Supply blood to ventricles
- Have thinner walls than ventricles
What are the 4 vessels of the heart?
1) Vena Cavae
2) Pulmonary a.
3) Pulmonary v.
4) Aorta
What are the 4 valves of the heart?
1) Tricuspid
2) Pulmonary
3) Mitral
4) Aortic
Where is the tricuspid valve located?
Between RA and RV
Where is the pulmonic valve located?
Between RV and Pulm a.
Where is the mitral valve located?
Between LA and LV
Where is the aortic valve located?
Between LV and aorta
Describe the heart valves
- One-way
- Pressure operated
- Passive
No contractile fibers in valve
Describe the blood flow pathway through the heart
S/IVC => RA (contraction, ^ pressure) => Tricuspid valve opens => RV (contraction) => pulmonic valve opens => pulmonary circulation (artery then vein) => LA (contraction) => mitral valve opens => LV (contraction) => aortic valve opens => aorta => blood circulation
What are the major types of blood vessels?
- Aorta
- Arteries
- Arterioles
- Capillaries
- Veins/venules
- Vena cavae
Describe the aorta
- Single outlet from left side of heart
- Dampens pulsatile pressure
Diameter: ~25mm
Describe arteries
- Thick walled, resist expansion
- Distributes blood to organs
Diameter: ~0.2 to 6.0mm
Describe arterioles
- Thicker walls than arteries (more smooth muscle)
- Highly innervated, sensitive to hormones, metabolites
- Primary site of regulation of vasculature resistance
Diameter: ~10 to 70 microm
Describe capillaries
- Smallest vessels
- Walls => single cell layer of endo cells
Diameter: <10 microm
Describe venules, veins
- Thin walls => similar diameter to arteries
- Holds most of blood volume
- Low pressure
- Has one-way valves to ensure blood flows in one direction
Describe the vena cavae
- Two branches: superior and inferior
- Large diameter (25-30 mm)
- Very low pressure
Describe the arrangement of microcirculation
- Arterioles to venules (AKA capillaries)
- Capillaries are site for gas, nutrient and waste exchange
- Blood flow determined by pressure gradients
- Blood flow regulated by arterioles and pre-cap sphincters
Describe the function of the lymphatic system
- Returns fluid from interstitial space to blood
- Depends on interstitial pressure
- Lymph vessels are low pressure, have one-way valves
What are the membranes/walls of the heart? From outside to in
- Epicardium
- Myocardium
- Endocardium
What encloses the entire heart?
The pericardium!
A fluid-filled membranous sac
Describe the atrioventricular valves
Tricuspid & mitral
- Between atria and ventricles
- Have chordae tendons
- Attach to papillary muscles in ventricles (stabilize/prevent prolapse of valves)
Describe the semilunar valves
Pulmonic & aortic
- Between ventricles and great arteries
- No chordae tendons
What are pre-capillary sphincters?
Smooth m. bands at junction of arteriole and capillary
