Blood Vessels Flashcards
1
Q
3 Classes of blood vessels
A
- Arteries: Carry blood away from heart (become progressively smaller as they branch - finally result in capillaries)
- Capillaries
- Veins: return blood to the heart & become progressively larger as they merge and are closer to heart
2
Q
Blood Vessel Tunics ( 3 layers)
-vasa vasorum
A
- Tunica Externa (adventitia): CT that helps anchor blood vessel to organ
Vasa Vasorum: Small network of arteries that supply blood to tunica externa
2.Tunica media: comprised of circularly arranged smooth muscle
-sympathetic input = vasoconstriction
-parasympathetic input = vasodilation - Tunica Intima (interna): composed of an endothelium (simple squamous lining inside of arteries and veins) and a subendothelial layer of areola CT
3
Q
Blood Vessel tunics - differences between artery and vein
A
- Vein has thin media layer, but very thick externa
- also has extensions of endothelial lining called valves that prevent the backflow of blood to lower parts of the body
- Arteries: need to maintain high pressure - have v. narrow lumen (space for blood to travel) and very thick media.
- When no blood in vein, it collapses (due to thin media)
4
Q
Types of arteries (3)
A
- Elastic arteries
- Muscular arteries
- Arterioles
5
Q
Elastic Arteries
A
- Largest of arteries
- most near the heart
- Elastic fibers present in all three tunics allows these arteries to stretch under the increased pressure generated by bloodflow from the heart
- branch into muscular arteries
-e.g. aorta, pulmonary, brachiocephalic, common carotids, subclavians
6
Q
Muscular Arteries
A
- Medium diameter arteries
- Possess elastic fibers in 2 concentric rings between the three tunics;
1. Internal elastic lamina (separates tunica intima & tunica media)
2. External elastic lamina (separates tunica media & tunica externa) - Have a proportionately thicker tunica media
7
Q
Arterioles
A
- smallest arteries
- less than 6 cell layers of smooth muscle in tunica media
- sympathetic innervation causes vasoconstriction (elevation of blood pressure)
- parasympathetic innervation causes vasodilation (lowering of blood pressure)
8
Q
Capillaries
A
- Smallest of all blood vessels
- Diameter only slightly larger than an erythrocyte
- wall = only tunica intima
- only type of blood vessel where metabolic exchange can occur between blood and cells outside of the bloodstream
9
Q
Capillary Beds
- metarteriole
- thoroughfare channel
- postcapillary venule
- true capillaries
A
- Formed from capillaries (10-100)
- Fed by a metarteriole (vessel branch of arteriole) - proximal end surrounded by smooth muscles, while distal end (called thoroughfare channel) lacks smooth muscles
- Thoroughfare channel connects to a postcapillary venule (start of vein system)
- Branches from metarteriole that begin w/ ring of smooth muscles of their walls = true capillaries
10
Q
Types of Capillaries (3)
A
- Continuous: most common type - endothelial cells form a continuous and complete lining, aided by presence of tight junctions
- Fenestrated: endothelial cells possess small holes to allow fluid exchange between blood and interstitial fluid (i.e. glomerulus)
- allows small molecules such as nutrients to release
- Sinusoid: have big gaps between endothelial cells that promotes transport of large molecules & cells to & from blood
- In liver and some lymphatic tissues & spleen
11
Q
Veins - what they do, function
-pressure compared to arteries
A
- blood vessels that drain capillaries & return blood back to heart
- Pressure in veins much lower than in arteries
- at rest, holds about 60% of body’s blood
- function as blood reservoirs
12
Q
Veins -size
- small, medium & large
- valves
- skeletal muscles’ role
A
- larger than venules
- smaller & medium sized travels w/ muscular arteries
- large veins travel w/ elastic arteries
- possess valves b/c blood pressure in veins too low to overcome force of gravity
- formed from tunica intima (prevent blood from pooling in limbs)
- skeletal muscles assist - as they contract, also pump blood towards heart (SKELETAL MUSCLE PUMP)
13
Q
Venules - what they are
- where located
- Diapedesis
A
- smallest veins
- smallest ones located at distal end of capillary bed & called postcapillary venules
- Diapedesis (migration of leukocytes from bloodstream to body) occurs through walls of postcapillary venules
- merge to form veins
14
Q
Blood Pressure -what it is
- Systolic vs diastolic
- how expressed
A
- Is the force per unit area that blood places on the inside wall of a blood vessel
- systolic pressure > dialostic pressure due to force of ventricle contraction
- expressed as ratio: numerator = systolic, denominator = diastolic
- average adult = 120/80 mmHg
- pressure produced in ventricles of heart
- pressure decreases as go further through network
15
Q
Factors that affect blood pressure (5)
A
- Increased blood volume
- increased cardiac output
- vasoconstriction
- some medicines & drugs (can either increase or decrease)
- overweight or less healthy tend to have increased blood pressure
16
Q
General arterial flow out of the heart
- What ascending aorta branches into (2)
- What aortic arch branches into (3)
A
-oxygenated blood pumped out of left ventricle into ascending aorta - gives off to two branches;
1. Left coronary artery
2. Right coronary artery
Aortic arch gives three branches;
1. Brachiocephalic trunk - bifurates into right common carotid & right subclavian arteries
2. Left common carotid
3. Left subclavian artery
17
Q
General arterial flow out of the heart
- Descending thoracic aorta
- when name changes
- When bifurcates (goes into 2)
A
- Descending thoracic aorta follows aortic arch & gives off several branches to thoracic wall (pretty much touches vertebral body)
- Called descending abdominal aorta when passes inferior & posterior to diaphragm
- at fourth lumbar vertebra, aorta bifurcates into left & right common iliac veins
- further divide into internal and external iliac arteries
18
Q
General venous return to heart
-Inferior & superior vena cava
A
- Inferior vena cava returns blood to right atrium from lower limbs, pelvis & perineum & abdominal structures
- superior vena cava formed from fusion of right & left brachiocephalic veins - drains into right atrium
19
Q
Blood flow through head and neck
-Major arteries
A
- Left & right common carotid arteries supply most of blood
- at superior border of thyroid cartilage, they divide into internal and external carotid arteries
20
Q
Blood flow through head and neck
-Major veins
A
- Venous blood return through internal jugular vein or external jugular vein
- both drain into subclavian vein & then into brachiocephalic vein
21
Q
Blood flow through cranium
A
- Most venous blood drains through dural venous sinuses
- these large veins formed between two layers of dura mater
- no valves in dural venous sinus system so blood can flow in more than just one direction
- these large veins formed between two layers of dura mater
22
Q
Blood flow through gastrointestinal tract
A
- 3 unpaired arteries emerge from anterior wall of descending abdominal aorta
- are responsible for supplying the organs of the gastrointestinal tract
- celiac trunk
- superior mesenteric artery
- inferior mesenteric artery
- are responsible for supplying the organs of the gastrointestinal tract
23
Q
Venous return from abdomin
- hepatic portal vein - where it goes
- what it is formed by (3)
A
- hepatic portal system is a network of veins that drains blood from gastrointestinal organs and shunts the blood to the liver
- Hepatic portal vein delivers nutrient rich blood to liver
- formed by merging of:
1. Inferior mesenteric vein (drains distal part of colon)
2. Splenic vein: drains spleen, pancreas & stomach
3. Superior mesenteric vein (drains small intestines, proximal part of colon, pancrease & stomach)
24
Q
Arterial flow through upper limb
-From subclavian to fingers
A
- Left and right subclavian arteries supply blood to upper limbs
- As subclavian artery passes over lateral border of first rib, called axillary artery
- supplies shoulder and thoracic region
- as passes inferior border of teres major muscle, name changes to brachial artery
- in cubital fossa, brachial artery bifurates into ulnar and radial arteries
- these arteries anastomose & form superficial & deep palmar arches in palm of hand
- digital arteries emerge from arches
25
Q
Superficial venous drainage of upper limb
A
- On dorsum of hand, dorsal venous network drains into basilic and cephalic veins
- in cubital fossa, these 2 veins connected by median cubital vein - common vein used for venipuncture
26
Q
Arterial flow through lower limb
A
- RIght and left external iliac artery supplies blood to lower limb
- as passes inferior to inguinal ligament, name changes to femoral artery - gives off a branch called deep femoral artery
- deep femoral artery supplies hip joint via medial and lateral circumflex arteries
- Popliteal artery (region behind knee)
- Have anterior tibial artery, posterior tibial artery and fibular artery
27
Q
Superficial venous drainage of lower limb
A
- On dorsum of foot, dorsal venous arch drains into great saphenous vein medially and small saphenous vein laterally
- great saphenous vein drains into femoral vein & small saphenous vein drains into popliteal vein
28
Q
Pulmonary circulation
A
- responsible for carrying deoxygenated blood from right side of heart to lungs & returning newly oxygenated to left side of heart
- In this circulation, arteries carry deoxygenated blood and veins carry oxygenated blood opposite of systemic circulation
- deoxygenated blood exits righ ventricle into the pulmonary trunk, bifurcates into right and left pulmonary arteries that go to lungs
- Arteries branch into arterioles, then capillaries and finally return to left atrium as pulmonary veins
29
Q
Fetal and Newborn Circulation
- features of fetus
- 3 things unique to fetal circulation
A
- Lungs don’t work in fetus - get O2 from umbilical vein
- is a hole b/w left and right atrium for blood to bypass lungs = foramen ovale (prevents developing lungs from overloading with blood)
- Ductus arteriosus, formen ovale & ductus venosus are unique to fetal circulation
- become ligaments once not needed
30
Q
Fetal and Newborn circulation;
What structures turn into after birth:
- Ductus arteriosus
- ductus venosus
- foramen ovale
- umbilical arteries
- umbilical vein
A
- Ductus arteriosus -ligamentum arteriosum
- ductus venosus-ligamentum venosum
- foramen ovale - fossa ovalis
- umbilical arteries -Medial umbilical ligaments
- umbilical vein - round ligament of liver (ligamentum teres)
