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Chapter 13 Blood Vessels and Circulation (13-1 Types of blood vessels…
Chapter 13 Blood Vessels and Circulation
13-1 Types of blood vessels
Tunica Media
the middle layer, contains smooth muscle tissue in a framework of collagen and elastic fibers
Tunica Externa
forms a sheath of connective tissue around the vessel
Tunica intima
innermost layer of a blood vessel
Vasoconstriction
these muscles in the vessel wall contract and the artery constricts
Vasodilation
relaxation increases the diameter of the artery and its central opening
Elastic arteries
large extremely resilient vessels with diameters of up to 2.5 cm
Muscular arteries
medium-sized, distribute blood to skeletal muscles and internal organs
Capillaries
only blood vessels whose walls permit exchange between the blood and the surrounding interstitial fluid
Consists of a single layer of endothelial cells inside a basement membrane
Capillary bed
capillaries do not function as individual units but as part of an interconnected network
Precapillary Sphnicter
gaurds the opening of each capillary, a band of smooth muscle
Depends on pressure and resistance
Veins
collect blood from all tissues and organs and return it to the heart
In the limbs, medium-sized veins contain valves
Folds of endothelium that function like the valves in the heart, preventing the backflow of blood
13-2 Blood pressure
Peripheral Resistance- R is opposition to blood flow usually due to friction
Vascular resistance, viscosity, and turbulence TPR rises
Blood viscosity high R and higher blood pressure
Total blood vessel length
Blood vessel Radius
MOST significant factor in determining Blood Pressure
Indirect Relationship
Pressure
Hydrostatic pressure comes from the heart
Circulatory pressure- 100 mm Hg base of aorta
Cardiovascular pressures within the systemic circuit
Blood pressure= the pressure exerted by blood on the wall of blood vessel
Pulse= the pressure wave that travels through arteries following left ventricular systole
Tachycardia= >100 bpm
Bradycardia= <60 bpm
Pulse pressure= difference between systolic & diastolic pressures
100 mm Hg (aorta)
35 mm Hg (arterial side capillary)
18 mm Hg (venule side of capillary)
2 mm Hg Vena Cava
13-3 Cardiovascular regulation
Autoregulation
Precapillary sphincters alter peripheral resistance (local changes)
vasodilators
Vasoconstrictors
Neural regulation
baroreceptors
detect changes in BP in aorta and carotid arteries
Chemoreceptors
detect changes in key blood chemical cocentrations
Hormones/endocrine regulations
Antidiuretic hormone
increases re absorption of water by the kidneys and causes vasoconstriction of arterioles during diuresis and during hemorrhage
Epinephrine and norepinephrine
increases CO and causes vasoconstriction of arterioles
Angiotensin II (Liver)
has four different targets that cause vasoconstriction of arterioles and causes the secretion of aldosterone, ADH & stimulates cardiac output
Aldosterone (Adrenal gland bc of Angiotensin II)
increases NA+ and water reabsorption in the kidneys
EPO
stimulates red blood cell production
Decrease BP
Atrial natiuretic peptide (ANP)
causes vasodilation of arterioles and promotes the loss of salt and water in urine
Histamine
causes vasodilation of arterioles (plays a role in inflammation)
13-4 Physiological stress
Exercise
at rest 5.8 liters per minute
Extensive vasodilation
peripheral resistance drops
capillary flow increases
Venous return increases
Skeletal muscle contractions
increased respiration rate (respiratory pump)
Cardiac output increases
Frank Starling principle (Ventricle reflex)
Brainbridge reflex (Atrial reflex)
Hemorrhage
Short term
Blood donation 500 ml 10%
Vasomotor enough to restore pressure & flow
Venous reserve (venocnstriction)
slow moving blood (liver, bone marrow, and skin)
restore 15-20% loss
sympathetic stimulation (major loss of blood)
E, NE, ADH, Renin
Long Term (Fluid retention)
ADH, aldosterone & increase thrist
EPO
Shock
Acute circulatory crisis
hypotension
pale, cool, and moist skin
confusion & disorientation (no blood to brain)
rapid and weak pulse
no urine
drop in blood pH
13-5 pulmonary and systemic circuits
Distribution of arteries and veins on left and right are identical
Vessels may undergo several name changes
Tissues and organs are serviced by several arteries and veins
13-6 Pulmonary Circuit
the vessels that carry blood from the right ventricle to the lungs, and the vessels that return the blood to the left atrium
pulmonary trunk
right and left pulmonary arteries (deoxygenated blood)
capillaries in lungs
Right and left pulmonary veins (oxygenated blood)
13-7 Systemic Circuit
the vessels that carry blood from the heart to body cells and back to the heart
Arterial system
the aorta is divided into the following regions
ascending aorta
aortic arch
thoracic aorta
abdominal aorta
terminates at the brim of the pelvis and branches into each leg = common iliac arteries
Principal Branches of the Aorta
Branches of the ascending aorta
Right and left coronary arteries
Branches of the aortic arch
Brachiocephalic (right side of the head and right arm)
right common carotid artery (right side of head)
External carotid artery (scalp)
Internal carotid artery (brain)
Vertebral (Cervical vertebrae/skull)
Basilar artery (brain)
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Right subclavian artery (right arm)
Axillary (Armpit)
Brachial (upper arm)
Radial (lateral forearm)
Ulnar (Medial forearm)
Palmar arches (Palm)
Digital (fingers)
Left common carotid artery (left side of head)
External carotid artery
Internal Carotid Artery
Left subclavian artery (left arm)
branches follow same pattern as right subclavian artery
Brnaches of abdominal aorta
Celiac trunk
Inferior phrenics
Superior Mesentric
Suprarenals
renal arteries
Inferior mesenteric
Branches of Common iliac arteries
External iliac artery (lower extremities)
Femoral artery
Venous system
Jugular veins (head)
Median Cubital vein
2 brachiocephalic veins
Superior Vena Cava
Coronary sinus
Cardiac veins
Hepatic vein
Hepatic portal vein
Great saphenous vein
Inferior Vena cava
Azygous system
Azygous vein and hemiazygous
13-8 Fetal circulation
Umbilical arteries
Umbilical vein
liver
Ductus venosus
Foramen Ovale
Ductus Arteriosus
becomes ligamentum arteriosum
13-9 Aging
Blood
decreased hematocrit
Constriction or blockage
pooling of blood (valves not working)
Heart
reduced cardiac output
changes in nodal or conducting cells
Blood vessels
Inelastic walls
Calcium deposits