topic 12

Question 1

what are the types of blood vessels?
Carry Donuts Real Easy Ron

Answer 1

Conducting Vessels:
Function: Transport blood from the heart to major regions of the body.
Examples: Aorta, pulmonary arteries.

Distributing Vessels:
Function: Direct blood to specific organs and tissues.
Examples: Brachial artery, femoral artery, radial artery.

Resistance Vessels:
Function: Regulate blood flow and pressure by changing diameter.
Examples: Small arteries, arterioles.

Exchange Vessels:
Function: Facilitate the transfer of gases, nutrients, and wastes between blood and tissues.
Examples: Capillaries, postcapillary venules.

Reservoir Vessels:
Function: Store and return blood to the heart.
Examples: Superior vena cava, inferior vena cava, great saphenous vein.

Question 2

innervation of blood vessels

Answer 2

Sympathetic Nervous System: Predominantly causes vasoconstriction via norepinephrine binding to alpha-1 adrenergic receptors. In specific cases, it can cause vasodilation via beta-2 adrenergic receptors.

Parasympathetic Nervous System: Has a limited direct role in blood vessel regulation. Causes vasodilation in specific regions via acetylcholine binding to M3 muscarinic receptors, leading to nitric oxide release.

Sensory Innervation: Involves baroreceptors and chemoreceptors that monitor blood pressure and chemical environment, facilitating reflex cardiovascular regulation.

Question 3

Anastomosis

Answer 3

1.Arterial : when 2 arteries merge, and provides collateral routes of blood supply like in the coronary circulation(arch, convergence,transverse-2 long linked by one small) eg circle of willis
2.Collateral anastomosis: forms a secondary route for blood flow between two vessels (arteries or veins) when the main pathway is compromised. e.g circl of Willis
3.Venous anastomosis: e.g Palmar Venous Arch (merging of palmar digital veins)
4.ArterioVenous : artery flow directly into vein bypassing capillaries e.g Deep veins collect deoxygenated blood from the skin tissues.

anastomosis: connection b/w 2 blood vessels

Question 4

capillaries : definition & structure

Answer 4

Capillaries are tiny blood vessels with thin walls, consisting of a single layer of endothelial cells supported by a basement membrane. They connect arterioles and venules, forming the site of exchange between the blood and surrounding tissues.

Structure

Endothelial Cells:
Single Layer- Capillary walls are composed of a single layer of endothelial cells, which are thin and flattened to facilitate the exchange of substances.

Pericytes:
Support Cells: Embedded within the basement membrane or adjacent to endothelial cells, pericytes provide structural support to capillaries and are involved in angiogenesis and vascular stability.

Intercellular Junctions:
Loose Junctions: Endothelial cells in capillaries have loose intercellular junctions, allowing for the passage of small molecules and fluids between cells.

Question 5

functions of capillaries

Answer 5

Gas Exchange:
Capillaries facilitate the exchange of oxygen and carbon dioxide between the blood and tissues through passive diffusion.

Nutrient Exchange:
Nutrients such as glucose, amino acids, and fatty acids are exchanged between the blood and tissues through capillaries, supplying cells with essential nutrients for metabolism.

Waste Product Removal:
Metabolic waste products such as carbon dioxide and urea are removed from tissues and transported in the blood to be eliminated through capillaries.

Hormone Transport:
Hormones and other signaling molecules are transported through the bloodstream to target tissues via capillaries, facilitating communication between organs and systems.

Fluid Exchange:
Capillaries are permeable to water, allowing for the exchange of fluids between the blood and interstitial fluid, helping to maintain fluid balance in tissues.

Question 6

types of capillaries

Answer 6

Continuous Capillaries:
Structure: Endothelial cells form a continuous lining with tight junctions, limiting the passage of large molecules.
Location: Found in most tissues, including muscle, skin, and the central nervous system.
Function: Facilitate selective permeability and regulate the exchange of small molecules and fluids.

Fenestrated Capillaries:
Structure: Endothelial cells have fenestrations or pores, allowing for increased permeability.
Location: Found in organs with high rates of filtration and absorption, such as the kidneys, small intestine, and endocrine glands.
Function: Facilitate rapid exchange of fluids and small solutes.

Sinusoidal Capillaries:
Structure: Large, irregularly shaped capillaries with large gaps between endothelial cells and an incomplete basement membrane.
Location: Found in organs such as the liver, spleen, and bone marrow.
Function: Allow for the passage of large molecules, cells, and proteins between the blood and tissues.