Circulation Flashcards
What do arteries do?
Carry blood away from the heart and branch into smaller arteries
What do veins do?
Carry blood to the heart and merge into larger veins
What joins arteries to veins
Capillaries
What are the layers of walls and arteries called?
Tunics
What are the layers of walls and arteries
Tunica Intima: Most inner layer; simple squamous epithelium and areolar CT
Tunica Media: Circularly arranged smooth muscle that can cause vasoconstriction
Tunica Externa: CT that aids in anchoring blood vessel
What are the small arteries found in the tunica externa?
Vasa Vasorum (to accomodate a blood supply to large blood vessels)
Elastic Arteries
Largest; contains elastic fibers in all three tunics and branch into the muscular arteries
Muscular Arteries
Medium size; two concentric rings of elastic fibers; inner ring is the internal elastic lamina which separates the tunica intima from the tunica media; outer ring is the external elastic lamina which separates the tunica media from tunica externa
Arteioles
Smallest; contain smooth muscle in their tunica media when contracted leads to an increase in BP and when relaxed it would lead to a drop
Blood flow is unidirectional except
Venous system of brain
Capillaries
-smallest of blood vessels
-only tunica intima (diameter the size of a erythrocyte)
-only blood vessel where metabolic exchange can occur between blood and tissues
-form capillary beds
Continuous Capillary
Most common, complete lining
Fenestrated Capillary
Contains pores that allow for fluid exchange.
Sinusoid Capillary
Has large gaps and incomplete basement membrane. Transports large molecules and cells to and from the blood.
Veins
Drain capillaries and return blood to the heart
-same layers as artereies but thinner esp tunica media
-60% of blood volume at rest known as blood resevoir
What is a metarteriole?
Feeds each bed; supplies true capillaries, each contains a ring of smooth muscle, that branch off the metarteriole to supply the tissue
What is the throughfare channel?
Connects last true capillary to a postcapillary venule which becomes the venous system.
What are the two major groups that veins are divided into?
Venules-smallest of veins (postcapillary are the smallest and is where diapedesis occurs)
Small/medium/large veins- Small and medium travel with muscular arteries while large travels with elastic arteries
What is the skeletal muscle pump?
squeezes veins when the muscle contracts and forces the blood in the vein to travel toward the heart
What is the respiratory pump?
The respiratory pump
functions in the abdominopelvic
cavity where the veins are
compressed when the
diaphragm contracts decreasing
the volume in the cavity and
increasing the pressure
■ When the diaphragm relaxes,
the volume in the thoracic cavity
decreases and the pressure
increases squeezing the veins.
■ Since the veins have one-way
valves, the blood is forced towards the heart
How does a pulse exist?
When the systolic and diastolic are not equal
-only in arteries, there is no more pulse in the capillaries
-BP is greatest in the aorta and almost zero in superior and inferior vena cava
What is systemic circulation?
All the vessels that extend to the body regions
What are two branches of the ascending aorta?
Right and left coronary arteries
What are the branches of the aortic arch?
1) Brachiocephalic trunk which bifurcates into the
right common carotid and the right subclavian
arteries
2) The middle branch is the left common carotid
artery
3) Final branch is left subclavian artery
What does the aortic arch become?
descending thoracic aorta until it crosses through the diaphragm when it then
becomes the descending abdominal aorta
What are the arteries that branch off of the descending thoracic aorta?
Bronchial arteries
What does the descending abdominal aorta branch into at the 4th lumbar vertebrae?
Left and right common iliac arteries
What do the common iliac arteries branch into?
Right and left internal/external iliac arteries
What forms the superior vena cava?
Fusion over the right and left brachiocephalic veins.
What does the superior/inferior vena cava drain into?
The right atrium
What forms the inferior vena cava?
The fusion of the left and right common iliac veins
What supplies most of the blood to the head and neck?
Right and left common carotid arteries
What do the right and left common carotid arteries branch into?
Left and right internal and external carotid arteries
What do the internal carotid arteries supply?
The brain
What do the external carotid arteries supply
Other structures in the skull
What drains blood from the head and neck?
Left and right internal/external jugular veins
What do the left and right internal/external jugular veins drain into?
Left and right subclavian veins
What do the right and left subclavian veins become?
right and left brachiocephalic veins
What forms the superior vena cava?
Right and left brachiocephalic veins
What forms 2/3’s of the cerebral arterial circle (circle of wilis)
internal carotid arteries
What forms the remaining 1/3 of the cerebral arterial circle (circle of wilis)
basilar artery
What forms the basilar artery?
Union of the right and left vertebral arteries
What do the vertebral arteries branch off into?
Right and left subclavian arteries
What do the vertebral arteries travel through?
Transverse foramina in the cervical vertebrae
What drains most cranial blood?
Dural venous sinuses?
-superior sagittal sinuses
-inferior sagittal sinus
-straight sinus
-occipital sinus
-r/l transverse sinuses
-r/l sigmoid sinuses
What do the sigmoid sinuses drain into?
Internal jugular veins
What supplies blood to the thoracic and abdominal walls?
Arteries that branch off of the thoracic and abdominal descending aorta
What returns blood from the thoracic and abdominal walls?
-right side drains into azygous vein
-inferior left side drains into the hemiazygous vein
-superior left side drains into the accessory hemiazygos vein
■ The hemiazygos and the accessory hemiazygos veins drain into the azygos vein
What does the azygous vein drain into?
Superior vena cava
What are the branches of the celiac trunk? (Blood supply to the gastrointestinal tract)
Left gastric artery, splenic artery, and common hepatic artery
What does the common hepatic artery give off?
hepatic artery proper, left and right hepatic arteries, right gastric artery, and gastroduodenal artery
What supplies blood to the gastrointestinal tract?
Celiac trunk and superior/inferior mesinteric arteries
What are the two pairs of arteries that branch off the descending abdominal aorta?
Right and left renal arteries and right and left gonaldal arteries
What drains the kidneys and gonadal organs?
Right and left renal veins (join the inferior vena cava)
Right and left gonadal veins (right gonadal vein drains in the inferior vena cava but left drains in the left renal vein)
What is the system that drains the gastrointestinal organs and delivers blood to the liver
Hepatic portal system
What makes up the hepatic portal veins?
inferior/superior mesenteric vein and splenic vein
What veins drain the liver?
RIght and left hepatic veins (join the inferior vena cava)
What supplies blood to the upper appendage?
Right and left subclavian arteries
What do the right and left subclavian arteries become at the level of the first rib?
Axillary artery
What does the axillary artery become at the inferior border of teres major?
Brachial artery
What does the brachial artery bifurcate into at the cubital fossa?
Radial and ulnar arteries
What do the radial and ulnar arteries become?
Superficial and deep palmar arches
What arises from the superficial and deep palmar arches?
Digital arteries
What drains the upper appendage?
Superficial and deep venous system
What is the superficial venous system that drains the upper appendage?
Dorsal venous network that drains into the basilic and cephalic vein. These two veins are joined by the median cubital vein in the cubital fossa
What is the deep venous system that drains the upper appendage?
Superficial and deep palmar arches that drain into the radial and ulnar veins. At the cubital fossa they become the brachial veins.
What forms the axillary vein
Brachial and basilic vein
What forms the subclavian vein?
Axillary and cephalic vein
What supplies blood to the lower appendage?
Right and left external iliac arteries
What does the external iliac artery become as it passes the inguinal ligament
Femoral artery
What does the femoral artery become in the popliteal fossa?
Popliteal artery (supplies the knee)
What does the popliteal artery bifurcate into?
Anterior and posterior tibial arteries (supplies anterior and posterior compartment of the leg)
What branches off of the posterior tibial artery?
Fibular artery (supplies lateral compartment of leg)
What branches off of the anterior tibial artery?
Dorsalis pedis artery (arcuate branches off of then becomes digital arteries to supply foot)
What is the superficial system that drains the lower appendage?
Great sapphenous vein that joins the femoral vein (medial side)
Small sapphenous vein that joins the popliteal (lateral)
Plantar venous arch that joins the posterior tibial vein
Dorsal venous arch that joins the great and small sapphenous veins
What is the deep system that drains the lower appendgage?
Posterior/anterior tibial veins
Fibular veins that merge with the posterior tibial veins
What forms the popliteal vein?
Fibular and posterior tibial veins
What does the popliteal vein become when it shifts to the anterior compartment of the thigh?
Femoral vein
What does the femoral vein become when it passes the inguinal ligament?
External iliac vein
What do the internal/external iliac veins from when they join?
Common iliac vein (join inferior vena cava)
What are the arteries that carry deoxygenated blood to the lungs?
Pulmonary trunk and left/right pulmonary arteries
(form capillaries that are associated with the alveoli)
What accomplishes blood return from the lungs?
Pulmonary veins
