21-Blood Vessels and Hemodynamics Flashcards
Layers of all blood vessels - 3
Tunica interna - Endothelium, elastic lamina for diffusion
Tunica Media - Smooth muscle, vasoconstriction, elastic lamina
Tunica Externa - contains nerves and blood vessels (vaso vasorum), anchors to surrounding tissue
Main blood vessel types - 5
Arteries - take blood away from heart Arterioles - arteries to capillaries, controls blood pressure Capillaries - nutrient and gas exchange Venules - capillary to vein Veins - take blood to the heart
6 Elastic arteries
Aorta Pulmonary Trunk Brachiocephalic Subclavian Common Carotid Common iliac
Arteriole functions - 4
Regulate blood flow into capillary
Regulate resistance, therefore BP, using sphincter. Vasomotion.
Metarteriole tapers to capillary
Vasoconstriction, vasodilation changes BP
More capillaries needed where, amount typically in use at a time
More needed for high metabolic demands (brain, liver, kidney)
25%
3 capillary types based on leakiness
Continuous - CNS, lungs, skin, muscle - no proteins cross
Fenestrated - small holes, kidneys, sm. intestines, endocrine glands
Sinusoids - large holes, proteins and RBCs can cross - red marrow, liver, spleen
Types of Venules - 2
Postcapillary - allows white blood cell migration, nutrient exchange
Muscular - Reservoir for large amount of blood storage
Osmosis - 3 things needed
3 types of pressure
Water movement, through a membrane, from lower to higher solute concentration
Osmotic pressure - due to different solute concentrations, solute Pulls the water
Hydrostatic pressure - Like BP, Pushes the water
Filtration pressure - Osmotic plus Hydrostatic summed
Capillary Exchange occurs 3 ways
Diffusion - with concentration gradient
Transcytosis - endocytosis and exocytosis
Bulk Flow - Pressure driven flow, liquids and solutes
Bulk Flow parts and process - 7
Blood contains Albumin protein, does not pass membrane
On arteriole side, BP pushes liquids and ions and nutrients to ISF due to Hydrostatic. Can also be some osmotic pushing same way. Filtration.
On veinous side, BP lower, osmotic pressure pushes liquids and “wastes” ISF to blood. Reabsorption.
Left over fluids go into lymph. If lymph cannot handle all, Edema.
Systemic Edema - why
Reduced Albumin protein in blood, so Hydrostatic pressure pushes fluids out of blood, but Osmotic pressure does not pull enough back into blood. Lymph is overwhelmed.
Blood flow - 2 factors, 3 reasons for one, SVR
Pressure difference
Resistance - lumen size, blood viscosity, vessel length
Systemic Vascular Resistance - arterioles more than other vessels
Venous return - 3 factors
Left Ventricle - pressure pushes blood around
Skeletal muscle pumps - legs major factor
Respiratory pump - lungs
Varicose veins - 3
Incompetent valves
Physical activity best way to hold off
Great Saphenous Vein likely - little muscle to pump, longest vein in body
Circulation Time, and define circulation
Circulation is drop of blood starting at right Atrium, traveling to foot, and back to right Atrium.
One minute.
Control of blood pressure and blood flow 1 + 5
Cardiovascular Center in Medulla
Baroreceptors, Chemoreceptors, proprioceptors
Cardiac accelerator nerves (sympathetic)
Vagus Nerve (X) parasympathetic
Baroreceptor reflexes - 2
Carotid sinus reflex - glossopharyngeal nerve (IX), for brain pressure
Aortic sinus reflex - systemic pressure, Vagus (X) nerve
Chemoreceptors
Excess CO2 - hypercapnia, stimulates CV center
Also input to Respiratory center
Hormonal control of blood pressure
Epi and NorEpi increase heart rate and force of contraction
Autoregulation of blood pressure - 2 + 2
Physical - warmth causes vasodilation, cold causes vasoconstriction
Vasodilation and Vasoconstriction chemicals
Low O2 causes systemic dilation, pulmonary constriction
Pulse rate - normal, low, high rates, names
Normal 60-100 beats per minute
Tachycardia above 100 beats per minute
Bradycardia below 50 beats per minute
Shock types - 4+3
Hypovolemic - blood loss, external trauma
Cardiogenic - heart attack - infarction
Vascular - decrease in SVR, anaphylactic (allergy), neurogenic (head/CV trauma), Septic (bacterial toxins)
Obstructive - block, embolism
Largest artery - 4 parts
Ascending Aorta - L&R coronary arteries
Arch of the Aorta - Brachiocephalic trunk (R common carotid, R subclavian), L common carotid, L subclavian. R&L vertebral off subclavian
Thoracic Aorta - Descending, to diaphragm
Abdominal Aorta - to R&L common iliac arteries. Branches Celiac trunk, Superior Mesenteric, Inferior Mesenteric.
Vertebral arteries - branches from, passes through, forms
Branches off of R&L subclavian arteries
passes through vertebral transverse foramen, through foramen magnum
Unite to form basilar artery
Subclavian becomes - 6, posterior versus anterior
Subclavian -> axial -> brachial -> radial, ulnar -> superficial & deep palmar arch.
radial feeds posterior
ulnar feeds anterior
Arteries used for bypass surgery
Posterior intercostal arteries
Abdominal aortic branches off of, and what they feed - 7
Celiac trunk - foregut Superior mesenteric artery - midgut Inferior mesenteric artery - hindgut Suprarenal arteries (3) - adrenal Renal artery - kidneys Gonadal (testicular or ovarian) - gonads Median sacral artery - sacrum, coccyx
Continuation of common iliac - 8
Common iliac -> external iliac & internal iliac
external iliac -> femoral & deep femoral
femoral -> popliteal -> anterior & posterior tibial
posterior tibial -> fibular (lateral leg)
Exceptions to rule veins follow arteries - 2
Internal Jugular veins drain brain - dural sinuses
Great saphenous veins - medial leg, longest veins, not well supported by muscle, likely to varicose.
Renal veins - longer, drains into it - 3
Left is longer, crosses over abdominal aorta
Left renal drains left suprarenal vein, left testicular/ovarian vein, left inferior phrenic vein
Hepatic portal circulation -
Splenic & superior mesenteric vein drain into hepatic portal vein into liver for nutrients
Hepatic artery feeds along side for O2
L&R hepatic veins leave liver, feed into inferior vena cava
Fetal circulation - not functioning, mixing with maternal
Lungs, kidneys, GI tract not functioning
Maternal and fetal blood do not mix. Placenta passes nutrients/wastes between.
Fetal circulation - systemic
From internal iliac artery to placenta via umbilical artery
Placenta via umbilical vein with O2, two branches -> liver, ductus venosus to inferior vena cava, intermingles O2 and not.
Fetal circulation heart - 2
Blood into right atrium crosses to left atrium via foramen ovale
Any pumped out right ventricle is passed pulmonary trunk to aorta via ductus arteriosus
Changes in infant after umbilical cord tied off - 5
Umbilical artery -> medial umbilical ligament
Umbilical vein -> ligamentum teres (round ligament)
Ductus venosus -> ligamentum venosum
Foramen ovale -> fossa ovalis
Ductus arteriosus -> ligamentum arteriosum
