Chapter 23: Vessels System (lecture) Flashcards
function of blood vessels
-flow and diffusion
-to maximize flow and minimize resistance
-maximize diffusion
what does the systemic circulation consist of?
consists of the blood vessels that extend to all body regions
what does the pulmonary circulation consist of?
consists of the vessels that take the blood to and from the lungs for the purpose of the gas exchange
3 classes of blood vessels
-arteries
-capillaries
-veins
process of systemic circulation including all 3 classes of blood vessels
-arteries branch into smaller vessels until they feed into the capillaries
-capillaries are where gas and nutrient exchange occurs
-from the capillaries, veins return blood to the heart
features of maximizing flow and minimizing resistance
-larger diameter
-shorter vessels
features of maximizing diffusion
-smaller diameter
both artery and vein walls have three layers called
tunics
what part of a blood vessel should be the thickest to maximize the rate of blood flow?
lumen
what is the space of the vessel through which blood flows called that tunics surround?
lumen
innermost layer of the blood vessel wall
tunica intima
what is tunica intima composed of?
-endothelium layer (a simple squamous epithelium lining of the blood vessel lumen)
-subendothelial layer (made up of a thin layer of areolar connective tissue)
middle layer of the blood vessel wall
tunica media
what is the tunica media composed of?
-smooth muscle cells
-concentric
-vasoconstriction (narrowing of the blood vessel lumen)/vasodilation (widening of the blood vessel lumen)
outermost layer of the blood vessel wall
tunica externa
what is the tunica externa composed of?
-areolar connective tissue that contains elastic and collagen fibers
-vasa vasorum (very large blood vessels require their own blood supply to the tunica external in the form a network of small arteries)
function of arteries
transport blood away from the heart
3 basic types of arteries
-elastic arteries
-muscular arteries
-arterioles
location and size of elastic arteries
-location: near the heart
-size: 1-2.5 cm in diamter (largest arteries)
distinctive feature and function of elastic arteries
-elastic fibers in all tunics
-high pressure
diameter and distinctive feature of muscular arteries
-diameter: 1cm- 3mm, medium-sized
-distinctive feature: thicker tunica media
-most named blood vessels (brachial, coronary, etc.)
description and function of arterioles
-smallest arteries, thin muscle
-controls the flow to capillaries
what are the capillaries?
smallest blood vessels that connect to the arteriole
length, diameter, and flow of capillaries
-1 mm long
-8-10 microns
-erythrocytes must travel in single-file
composition (layers) of capillaries
only tunica media
what are capillary beds?
group of capillaries functioning together
function and flow type of veins
-return blood to heart
-low pressure system
structure of veins
-thin walls
-thin tunica media
-collapse without blood
features of veins
-backflow valves
-blood reservoir
-more anastomoses
what happens in a backflow valve?
-most veins contain numerous valves formed primarily of tunica intima and strengthened by elastic and collagen fibers.
-thus, as blood flows superiorly in the limbs, these one-way valves close to prevent backflow
process of skeletal muscle pump
as the skeletal muscles contract, veins are squeezed to help pump the blood toward the heart
what are varicose veins?
-dilated, tortuous (having many curves or twists) veins
-valves in these veins became nonfunctional, causing blood to pool in one area and the vein to swell and bulge
what are blood reservoirs?
-at rest, the body’s veins hold about 60% of the body’s blood, thus veins function as blood reservoir
what are anastomoses?
-the site where two or more arteries converge to supply the same body region
-provide alternate blood supply routes to body tissues or organs
definition of pulse
rhythmic throbbing of arterial wall
what does a pulse measure?
-heartrate
-coarse blood pressure
-absence of flow to a region
definition of pulse point
-artery compressed against a bone
common pulse points
-brachial artery
-radial artery
-common carotid artery
-femoral artery
-facial artery
-dorsalis pedis artery
-popliteal artery
-posterior tibial artery
-superficial temporal artery
arterial pathways: ascending aorta
-ascending aorta: oxygenated blood is pumped out of the left ventricle of the heart and enters the ascending aorta
-left and right coronary arteries: emerge immediately from the wall of the ascending aorta and supply the heart
arterial pathways: arch of aorta
arch of aorta (aortic arch): ascending aorta curves towards the left side of the body and becomes aortic arch
3 main arterial branches emerge from arch of aorta
-brachiocephalic trunk: bifurcates into 2 branches
-left common carotid artery: supplying the left side of the head and neck
-left subclavian artery: supplying the left upper limb and some thoracic structures
brachiocephalic trunk bifurcates (divide into two branches)
-right common carotid artery: supplying arterial blood to the right side of the head and neck
-right subclavian artery: supplying the right upper limb and some thoracic structures
arterial pathways: head and neck
-common carotid artery: supply most of the blood to the head and neck
-internal carotid artery: supplies structures internal to the skull
-external carotid artery: supplies structures external to the skull
-vertebral artery: emerge from the subclavian arteries
parts of the common carotid artery
-carotid body
-carotid sinus
arterial pathways: upper extremities
-axillary artery
-brachial artery
-radial artery
-ulnar artery
-palmar arch
-digital arteries
where is the brachial artery located?
inferior border of teres major
what happens in the radial artery?
pulse
arterial pathways: abdominal aorta
-unpaired arteries
what are the unpaired arteries of the abdominal aorta?
-celiac trunk
-superior mesenteries artery
-inferior mesenteric artery
location of celiac trunk
under diaphragm
branches of celiac trunk
-left gastric artery
-splenic artery
-common hepatic artery
location of superior mesenteric artery
-to small intestine
-pancreas
-first 2/3 of large intestine
location of inferior mesenteric artery
to 1/3 large intestine
arterial pathways: abdominal aorta paired branches
-renal arteries
-gonadal arteries
types of gonadal arteries
-testicular
-ovarian
arterial pathways: pelvic region
-common iliac artery: descending abdominal aorta bifurcates into left and right common iliac arteries
-internal iliac artery: supply pelvic and perineal structures
-external iliac artery: supply to the lower limb
left and right common iliac arteries divide into what?
internal iliac artery & external iliac artery
arterial pathways: lower limb
-femoral artery
-popliteal artery
-anterior tibial artery
-posterior tibial artery
-dorsalis pedis artery
function of veins
merge to return deoxygenated blood to the heart
superficial veins of upper extremities
-basilic vein: runs adjacent to the medial surface of the upper limb
-cephalic vein: runs alongside the lateral aspect of the upper limb
-median cubital vein: connects the cephalic and basilic veins
location and significance of median cubital vein
-location: connects two
-significance: blood draws, put in IV
superficial veins of lower extremities
-great saphenous vein
-lesser saphenous vein
size, location, significance, and end of great saphenous vein
-size: longest vein
-location: medial thigh & leg
-significance: vessel source for coronary bypass
-end: empties into femoral vein
location and end of lesser saphenous
-location: posterior leg
-end: empties into popliteal vein
venous return from the brain
-dural venous sinuses: drain into internal jugular vein
-internal jugular vein
parts and function of dural venous sinuses
-dura mater
-function: receive excess cerebrospinal fluid (CSF)
parts of the internal jugular vein
-jugular foramen
-sigmoid sinus and inferior petrosal sinus
clinical application of hematoma
-subdural hematoma
-epidural hematoma
definition, cause, and progression of subdural hematoma
-definition: bleeding into space between dura mater and arachnoid mater
-cause: torn venous sinus
-progression: slow but fatal
definition, cause, and progression of epidural hematoma
-definition: artery torn
-cause: bleeding outside meninges
-progression: fast and fatal
