Cardiovascular System Flashcards
Blood Vessels
- delivery system of dynamic structures that begins and ends at heart
- work with lymphatic system
- Transports nutrients (sugars, fats, proteins), oxygen, water, hormones, immune system, waste
Capillaries
- Smallest blood vessels with thin walls, facilitating the exchange of nutrients and waste
- Directly serve cellular needs, where delivery and pick up of fluid happens.
5 characteristics of capillaries
-Exchange nutrients and waste.
-Leaky to allow transfer in and out.
-Lowest pressure: thin walls offer minimal resistance to blood flow
-More numerous.
-Same amount of fluid should be going in and out.
Arteries
carry blood away from heart; oxygenated
Exception for Arteries and Oxygenated
pulmonary circulation and umbilical vessels of fetus contain deoxygenated blood
Veins
carry blood toward heart; deoxygenated
Exception for Veins and Deoxygenated
pulmonary circulation and umbilical vessels of fetus which bring oxygenated blood
Pressure in Artery vs Vein
High pressure in arteries and low pressure in veins
Muscle in Artery vs Vein
Arteries - more muscle to maintain pressure
Veins - Less muscle because blood must go through muscles to travel to heart
Valves in Artery vs Vein
- arteries do not have valves
- veins have valves to prevent backflow due to low pressure
Blood Color in Artery vs Vein
Artery - Red
Vein - purple
Tunica Intima in Arteries and Veins
thin layer endothelium
in both
Tunic Media in Arteries vs Veins
Arteries - thick muscle layer to allow for constriction to control pressure and amount of blood passing
Veins - thin muscle layer
Tunica Externa in Arteries vs Veins
Arteries - thin layer of collagen
Veins - thick layer of collagen
Lumen
- hole in the middle of both veins and arteries
Vaso Vasorum
smaller arteries and veins within the tunica externa
in both veins and arteries
Endothelium
- includes tight junctions and is lined with epithelial cells to prevent leaking of blood
4 causes of Edema
- Increased hydrostatic pressure
- Decreased osmotic pressure
- Increased capillary permeability
- Blocked lymphatics
Increased Hydrostatic Pressure
- When the pressure inside the blood vessels (capillaries) is too high, fluid is pushed out into the surrounding tissues.
- This can happen with conditions like high blood pressure, where the force of blood against the vessel walls is too strong.
Decreased osmotic pressure
- Proteins in your blood, especially albumin, create osmotic pressure to pull back fluid
- If there’s too little protein in your blood, perhaps due to liver or kidney disease, the fluid isn’t pulled back in as effectively, leading to swelling.
Increased Capillary Permeability
- When the capillaries become
more permeable, fluids and proteins leak out into the surrounding tissues, causing swelling
Blocked lymphatic
- If the lymphatic vessels are blocked or removed, as can happen with cancer treatment when lymph nodes are removed, fluid can’t drain properly, leading to swelling.
Blood Pressure (BP) Definition
- Force per unit area exerted on wall of blood vessel by blood.
BP Measurement
- Expressed in mm Hg; measured as systemic arterial BP in large arteries near heart.
Blood Pressure Function
Pressure gradient provides driving force that keeps blood moving from higher- to lower-pressure areas.
Two types of BP?
Systolic and Diastolic.
Systolic
- when heart contracts
Diastolic
Pressure in the arteries when heart relaxes.
Dos systolic or diastolic contribute more to BP and why?
Diastolic contributes more to mean pressure because heart spends more time relaxing.
Starling Equation
Net fluid movement = K_f * [(P_c - P_i) - σ(π_c - π_i)]
K_f in Starling Equation
filtration coefficient, a measure of capillary permeability.
P_c
the capillary hydrostatic pressure
P_i
is the interstitial hydrostatic pressure.