Red blood Cells Flashcards
Tell me the pathway of circulation around the body
The heart Arterial system Capillary bed - Venous system Lymphatic Venous system
What are the three layers of blood vessels
The tunica Intima = endothelium + connective tissue
The tunica media = muscle and connective tissue
The tunica externa = thick layer of connective tissue
Tell me more about the tunica intima
lined with simple squamous epithelium = endothelium
continuous throughout the entire vascular system
endothelium releases endothelins (locally acting hormones) that can constrict smooth muscle within the walls of the vessels to increase blood pressure
What is deep in the endothelium
basement membrane or basal lamina, binds endothelium to connective tissue
In larger arteries what is there as well as the basement membrane
thick, distinct layer of elastic fibres known as internal elastic membrane at the boundary of the tunica media, provides structure whilst allowing vessel to stretch
Tell me about the Tunica media
Composed of concentric layers of helically arraigned smooth muscle cells
Contains varying amounts of elastic fibres which support the muscle cells
Thickest layer in arteries , much thicker in A than v
What are vasodilation and vasoconstriction
Vasodilation = the relaxation of the circular muscles causing the opposite
Vasoconstriction = contraction of the circular muscles = decrease in the diameter of the vessel lumen
Tell me about the tunica externa
A sheath of longitudinally orientated connective tissue composed of primarily collagen type 1 fibres
This is the thickest in veins
Tell me about elastic large arteries
mainly elastic
conducting arteries
expand during systole, while elastic recoil during diastole helps drive blood onwards
Tell me about muscular arteries
- relatively thick layer of circular smooth muscle in their tunica media
- control distribution of blood to regions and organs
- regulate blood flow by contraction or relaxation
- They can accommodate an increase in diameter
- they can contract to prevent haemorrhage
Name me the artier of the upper limb
Subclavian Axillary Brachial Radial Ulnar
What is anastomosis
when one vessel plugs into another, arterial anastomosis ensures blood supply to the hand and fingers
what must you note about the subclavian and the axillary and brachial arteries
The originate from the same artery
What must joints have to prevent compromised flow when contricted
co-lateral flow, in anastomosis
Where is the deep and superficial palmar arches are derived from
both the radial and ulnar arteries
Tell me about the blood vessels if the thorax
The main defending thoracic aorta
The Abdominal Aorta, this splits into the common iliac arteries which supply segmented blood flow to the abdomen
Arteries of the lower limb
In the groin = femoral artery (this was the external iliac but becomes femoral), vein lies medially and nerve laterally
Arterioles
arteries less than 0.5mm thick in diameter
Metarterioles
same diameter as capillaries (7 to 9 um) but have a layer of smooth muscle in their walls
capillaries
tube of endothelium only
What are the methods by which nutrients, hormones, 02 etc are exchanged
active transport passive transport -osmosis -diffusion -filtration -Facilitated Transport
Tell me more about capillaries Basal lamina
splits to enclose pericytes (myoepithelial cells)
What is blood flow through the capillary regaled by
pre-capillary sphincter
veins
70% of blood volume
smallest are venues
Leukocytes can pass through the walls of the venules (diapedesis) and escape into surrounding connective tissue
