25/26. Blood Vessels Flashcards
Characteristics of arteries
Carry blood away from heart
Depicted in red
Basics of veins
Carry blood towards the heart
Often depicted in blue
Generally multiple veins paired with single artery
3 layers common to arteries and veins and space within
Tunica intima
Tunica media
Tunica externa (adventitia)
Space within called lumen
Tunica intima
Deepest, simple squamous epithelium (endothelium)
Tunica media
Contains smooth muscle to control blood flow
Thicker in arteries than veins
Tunica externa
Outer layer
Connective tissue anchors vessels to other structures
Vasoconstriction
Contraction of smooth muscle in tunica media
Decreases blood flow through lumen
Vasodilation
Relax smooth muscle in tunica media
Increases blood flow through lumen
Types of arteries
Elastic arteries, muscular arteries, and arterioles
Characteristics of elastic arteries
Largest, closest to heart
Elastic fibers allow expansion when blood is pumped
E.g., aorta, pulmonary, brachiocephalic, common carotid, subclaviam, and common iliac arteries
Branch into musclar arteries
Characteristics of muscular arteries
Medium-sized arteries distribute blood to organs & tissues
Less elastic tissue and relatively thicker tunica media
Control flow of blood with smooth muscle
Branch into arterioles
Characteristics of arterioles
Smallest arteries
Smallest arterioles only have endothelium and single layer of smooth muscle
Branch into capillaries
Characteristics of Capillaries
Smallest blood vessels
Only one RBC can pass through a capillary at a time
Form a “bed” or branching of vessels for exchange of gases & nutrients
Composed of tunica intima (endothelium & basement membrane)
Types of veins
Venules and veins
Characteristics of venules
Smallest of veins
Run with arterioles
Have thin layer of smooth muscle, little ability to vasoconstrict
Merge to form larger venules, then veins
Characteristics of veins
Small & medium veins run with muscular arteries
Large veins run with elastic arteries
Low pressure in veins, need valves for one-way flow
Skeletal muscle pump
Skeletal muscle contraction and relaxation help move venous blood
Muscles squeeze veins, push blood towards heart
Inactivity results in greater risk of clot formation
Respiratory pump
IVC ascends in abdomen and thorax
Does not have skeletal muscle pump, assist from diaphragm
Inhalation - diaphragm flattens and increases abdominal pressure, lowers thoracic pressure, and blood in IVC is pushed towards heart
Arteries leaving the heart
Right and left common carotid arteries, right and left subclavian arteries, brachiocephalic trunk, ascending aorta, aortic arch, and thoracic aorta
Parts of the Common carotid artery
Splits into internal and external carotid arteries
Internal carotid passes through skull to supply brain
External carotid supplies superficial structures of head and neck
Branches of external carotid artery and where they supply
Superior thyroid a. - supply thyroid gland
Lingual a. - supply tongue
Facial a. - supply face
Occipital a. - supply back of head
Maxillary a. - supply muscles of mastication and teeth
Superficial temporal a. - supply scalp
Characteristics of vertebral arteries
Branches from subclavian arteries
Travel superiorly in transverse foramina in cervical vertebrae
Enter cranium through foramen magnum
Left and right arteries join to form basilar artery
Blood supply to the brain consists of
Internal carotid arteries and vertebral arteries
Characteristics of internal carotid arteries
Branch into anterior and middle cerebral arteries
Anterior cerebral arteries connect via anterior communicating arteries
Characteristics of vertebral arteries supplying the brain
Form basilar artery
Basilar artery gives off left and right posterior cerebral arteries
Posterior cerebral arteries connect to internal carotid arteries through posterior communicating arteries
What is the circle of Willis
Circle of arteries supplying the brain
Formed by posterior cerebral, posterior communicating, internal carotid, anterior cerebral, and anterior communicating arteries
Arteries that supply blood to upper extremities
Subclavian artery travels over first rib and under clavicle and becomes axillary artery
Axillary artery supplies shoulder and lateral thorax and becomes brachial artery as it passes Teres major muscle
Brachial artery supplies blood to arm and splits into radial and ulnar arteries after passing elbow
Radial and ulnar arteries supply forearm and wrist before splitting into superficial and deep palmar arches which supply the hand
Blood supply to thorax
Aorta arches back and to the left becoming the descending or thoracic aorta
Thoracic aorta gives off posterior intercostal arteries
Internal thoracic arteries are on either side of sternum, branch from subclavian arteries, and give off anterior intercostal arteries, which anastomose with posterior intercostal arteries
Blood supply to the abdomen
Thoracic aorta passes the diaphragm to become the abdominal aorta (has 3 unpaired central branches)
Paired renal arteries supply the kidneys
Gonadal arteries supply gonads
Abdominal artery splits into left and right common iliac arteries
Branches of abdominal aorta
- Celiac trunk- supplies stomach, liver, spleen, gallbladder, pancreas, and duodenum
- Superior mesenteric artery- supplies jejunum, ileum, appendix, ascending colon and transverse colon
- Inferior mesenteric artery- supplies descending colon, sigmoid colon, and rectum
Iliac arteries
Common iliac arteries enter pelvis and divide into internal and external iliac arteries
Internal iliacs supply pelvic organs, gluteal region, and external genitalia
External iliacs leave pelvis to become femoral arteries in the thigh
Arteries in lower extremity
Supplies the muscles of the thigh
Passes through back of knee (popliteal fossa) to become the popliteal artery
In the leg, popliteal artery branches into anterior tibial artery, posterior tibial artery, and fibular artery
Where to arteries of the leg supply
Anterior tibial artery: supply anterior compartment of leg and dorsum of foot
Posterior tibial artery: supply posterior compartment of leg and plantar foot
Fibular artery: supply lateral compartment of leg
Veins approaching the heart
Right and left internal jugular veins, right and left subclavian veins, right and left brachiocephalic veins, and superior and inferior vena cava
External jugular vein
Superficial to sternocleidomastoid
Carries blood from neck and scalp
Joins with internal jugular vein at base of neck
Internal jugular vein
Begins at jugular foramen (base of skull)
Carries blood from brain (dural sinuses), orbit, and face
Deep to sternocleidomastoid
Deep veins of upper extremity
Run with arteries with the same name
Radial and ulnar veins drain blood from hand and forearm and join near elbow as brachial vein
Brachial vein drains blood from arm and becomes axillary vein in the axilla
Axillary vein receives blood from shoulder, lateral thoracic wall, and upper extremity and becomes subclavian vein under clavicle
Subclavian vein joins with internal jugular vein to become the brachiocephalic vein
Superficial veins do upper extremity and how they connect
Also called cutaneous veins
Basilic vein runs along medial side of arm and forearm, joins axillary vein
Cephalic vein runs along lateral side of arm and forearm, joins subclavian vein
Median cubital vein connects Cephalic and basilic veins in the cubital fossa (common place for venipuncture)
Veins of the thorax- azgos system
Posterior intercostal veins drain blood from intercostal spaces
Left and right sides include different veins
Azygos vein returns blood to superior vena cava
Veins of right and left sides of thorax
Right side includes azygos vein that collects blood from posterior intercostals
Left side:
Lower left region has hemiazygos vein that collects blood from posterior intercostals
Upper left region has accessory hemiazygos vein that collects blood from posterior intercostals
Both return blood to azygos vein
Portal vs caval drainage
Drainage of venous blood in the abdomen proceeds directly into the inferior vena cava (caval system) or the hepatic portal vein (portal system)
Caval system: Receives blood from liver, kidneys, gonads, pelvic organs, external genitalia, and lower extremities
Portal system: receives blood from the intestines to be filtered in the liver
Characteristics of Caval system (IVC)
IVC receives blood from renal veins (draining from kidneys) and gonadal veins(draining from gonads)
IVC splits into the right and left common iliac veins
Iliac veins
Each common iliac vein splits into an internal and external iliac vein
Internal iliac receives blood from pelvic organs, external genitalia, and gluteal region
External iliac receives blood from lower extremity, becomes the femoral vein in thigh
Deep veins of lower extremity
Posterior tibial vein drains blood from the foot and posterior compartment of leg
Anterior tibial vein drains from anterior compartment of leg
Fibular vein drains blood from lateral compartment of leg
All 3 veins join to form popliteal vein behind knee
Popliteal vein moves around the medial side of the thigh to become the femoral vein that drains the thigh
Superficial veins of lower extremity
Great saphenous vein travels along medial leg and thigh collecting superficial blood of lower extremity and empties into femoral vein in upper thigh
Small saphenous vein travels along posterior leg collecting superficial blood from leg and empties into popliteal vein
Portal system
Hepatic portal vein receives blood from the digestive tract and accessory organs to be filtered by liver
Nutrients and harmful blood agents are removed
Filtered blood in liver sent to IVC
Superior mesenteric, inferior mesenteric, and splenic veins empty into hepatic portal vein
