ch 21 Jarvis peripheral vascular & lymphatic sys Flashcards
contain elastic fibers, which allow their walls to stretch with systole and recoil with diastole
Arteries
which control the amount of blood delivered to the tissues
-control the rate of blood flow.
muscle fibers (vascular smooth muscle [VSM])
is palpated in front of the ear
temporal artery
is palpated in the groove between the sternomastoid muscle and the trachea
carotid artery
major artery supplying the arm is the
-which runs in the biceps-triceps furrow of the upper arm and surfaces at the antecubital fossa in the elbow medial to the biceps tendon
brachial artery
below the elbow the brachial artery bifurcates into the
ulnar (difficult to feel) and radial arteries
ulnar and radial arteries run distally and form two arches supplying the hand
called the superficial and deep palmar arches.
, which passes under the inguinal ligament
femoral artery
travels down behind the medial malleolus and forms the plantar arteries in the foot.
back of the leg the posterior tibial artery
is a deficient supply of oxygenated arterial blood to a tissue caused by obstruction of a blood vessel.
Ischemia
affects noncoronary arteries and usually refers to arteries supplying the limbs. It usually is caused by atherosclerosis, and less commonly by embolism, hypercoagulable states, or arterial dissection.
Peripheral artery disease (PAD)
absorb CO2 and waste products from the periphery and carry them back to the heart
veins
Each arm has two sets of veins: .
superficial and deep
are in the subcutaneous tissue and are responsible for most of the venous return.
superficial veins
The legs have three types of veins
Veins in the Leg.
run alongside the deep arteries and conduct most of the venous return from the leg
- femoral
- popliteal
- As long as these veins remain intact, the superficial veins can be excised without harming the circulation.
- deep veins (Veins in the Leg.)
superficial veins are the great and small saphenous veins. The great saphenous vein, inside the leg, starts at the medial side of the dorsum of the foot.
- Blood flows from the superficial veins into the deep leg veins.
- superficial veins are the great and small saphenous (Veins in the Leg.)
are connecting veins that join the two sets. They also have one-way valves that route blood from the superficial into the deep veins and prevent reflux to the superficial veins.
- Perforators(Veins in the Leg.)
are a low-pressure system
-do not have a pump to generate their blood flow, they need a mechanism to keep blood moving
veins
(1) the contracting skeletal muscles that milk the blood proximally, back toward the heart;
(2) the pressure gradient caused by breathing, in which inspiration makes the thoracic pressure decrease and the abdominal pressure increase;
(3) the intraluminal valves, which ensure unidirectional flow. Each valve is a paired semilunar pocket that opens toward the heart and closes tightly when filled to prevent backflow of blood.
3 mechanism to keep blood moving
. When walking, the calf muscles alternately contract (systole) and relax (diastole). In the contraction phase the gastrocnemius and soleus muscles squeeze the veins and direct the blood flow proximally. Because of the valves, venous blood flows just one way—toward the heart.
calf pump or peripheral heart (in legs)
is lower, walls of the veins are thinner than those of the arteries.
venous pressure
Veins have a larger diameter and are more distensible; they can expand and hold more blood when blood volume increases. This is a compensatory mechanism to reduce stress (preload) on the heart. Because of this ability to stretch, veins are called
capacitance vessels.
depends on contracting skeletal muscles, competent valves in the veins, and a patent lumen
Efficient venous return