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Chapter 13, Chapter 13 (13.5 Pulmonary and Systemic Circuits…

- - - - based on local tissue concentrations (O2, CO2, pH
        
        vasoconstrictors
        
        vasodilators
  - - - vasomotor inhibited (dilate)
      - cardioinhibitory center stimulated
        
        parasympathetic
      - cardioaccelteratory center inhibited
        
        sympathetic
    - - vasomotor stimulated (constrict)
      - cardioinhibitory center inhibited
        
        parasympathetic
      - cardioaccelatory center stimulated
    - - input to centers: (CV), vasomotor, and medulla oblongata
        
        nerve impulses are sent to the centers from three areas
        
        baroreceptors (or pressoreceptors) that detect changes in BP in aorta and crotid arteries
        
        chemoreceptors that detect changes in key blood chemical concentrations (H+, CO2, and O2)
        
        higher brain centers
  - - - hormones that increase BP
        
        entidiuretic hormone
        
        increases reabsoption of water by the kidneys (DCT), and causes vasoconstriction of arterioles during diuresis and during hemorrhage
        
        epinephrine and norepinephrine
        
        increases CO (rate and force of contraction) and causes vasoconstriction of arterioles
        
        angiotensin II (liver)
        
        (renin released from kidneys) has four different targets that cause vasoconstriction of arterioles and causes the secretion of aldosterone
        
        aldosterone
        
        increases Na+ and water reabsoption in the kidneys
        
        EPO
        
        stimulates red blood call production
      - Hormones that decrease BP
        
        Antrial natriuretic peptide (ANP)
        
        causes vasodilation of arterioles and promotes the loss of salt and water in urine
        
        Histamine
        
        causes vasodilation of arterioles (plays a key role in inflammation)
- - - - exchange of nutrients
    - - liver
      - ductus venosus
        
        inferior vena cava
    - - rise from internal iliac arteries
- - - - aneurysm, stroke, myocardial infarction, or massive blood loss
- - - - total peripheral resistance
        
        for blood to flow circulatory pressure has to be ^ TPR
        
        resistance is the opposition to blood flow primarily due to friction. this friction depends on three things:
        
        blood viscosity (^ viscosity : ^R : ^BP
        
        normally constant
        
        direct relationship
        
        Total blood vessel length (^ blood vessel length : ^R : ^BP)
        
        normally constant
        
        direct relationship
        
        Blood Vessel radius (^ radius : v R : v BP)
        
        most significant factor in determining blood pressure
        
        indirect relationship
        
        vascular resistance, viscosity, and turblence
    - - circulatory pressure 100 mm Hg base of aorta (pressure gradient)
        
        needed to force blood through arterioles and capillaries
        
        arterial pressure (blood pressure)
        
        capillary pressure
        
        venous pressure
      - liquids cannot be compressed (hydrostatic pressure)
        
        liquid will flow from high to low
  - - - lessens as the distance from the heart increases
        
        100 mm Hg Aorta vs. 2 mm Hg vena cava
    - - instrument used is called a sphygmomanometer
      - brachial artery is typically used
    - - strongest in arteries closest to heart
      - commonly measured in redial artery at wrist
      - normal pulse = 70-80 bpm
        
        bradycardia < 60bpm
        
        tachycardia > 100bpm
    - - in clinical use, we most commonly refer to arterial blood pressure because the blood pressure in the veins is essentially insignificant
      - the arterial blood pressure rises to its maximum during systole (contraction) and falls to its lowest during diastole (relaxation)
      - in normal adults at rest, the BP = 120 mm Hg / 80 mm Hg
    - - capillary pressure pushes on the capillary walls
        
        permeably to ions, nutrients, organic wastes, dissolved gasses, and water
        
        capillary hydrostatic pressure vs. blood osmotic pressure
        
        100 mm Hg (aorta)
        
        35 mm Hg (arterial side capillary)
        
        arterial difference = 65 mm Hg
        
        18 mm Hg (venule side of capillary)
        
        2 mm Hg (vena cava)
        
        pressure of veins = 16 mm Hg
        
        CHP ^ BOP (arterial side) fluid moves into tissues
        
        BOP ^ CHP (venule side) fluid moves into vessel
        
        CHP = BOP no net fluid movement
      - Capillary exchange has four parts
        
        communication between plasma and interstitial fluid
        
        speeding distribution throughout tissues
        
        assisting the movement of insoluble lipids and tissue proteins
        
        flushing bacterial toxins and chemical stimuli to the lymphatic system
- - - - the aorta is divided into:
        
        ascending aorta
        
        right coronary artery (myocardium)
        
        left coronary artery (myocardium)
        
        aortic arch
        
        brachiocephalic
        
        axillary (armpit)
        
        brachial (upper arm)
        
        radial (lateral arm)
        
        right subclavian a. (right arm)
        
        ulnar (medial forearm)
        
        right common carotid a. (right side of head)
        
        internal carotid a. (brain)
        
        external carotid a. (scalp)
        
        vertebral (cervical vertebrae / skull)
        
        basilar a. (brain)
        
        1 more item...
        
        palmar arches (palm)
        
        digital (fingers)
        
        left common carotid artery (left side of head)
        
        external carotid a.
        
        internal carotid a.
        
        left subclavian artery (left arm)
        
        thoracic aorta
        
        superior phrenics (superior diaphragm)
        
        bronchial arteries (bronchi of the lungs)
        
        esophageal arteries (esophagus)
        
        intercostals (intercostal / chest muscles)
        
        abdominal aorta
        
        inferior phrenics (inferior diaphragm)
        
        celiac trunk (artery)
        
        left gastric a. (left stomach)
        
        splenic artery (spleen)
        
        common hepatic a. (liver)
        
        superior mesenteric (small intestine, cecum, ascending / transverse colon, pancreas)
        
        suprarenals (adrenals)
        
        renal arteries (kidneys)
        
        gonadal arteries (ovarian / testicular)
        
        inferior mesenteric (descending / sigmoid colon, rectum)
        
        common illiac arteries
        
        external iliac a. (lower extremities)
        
        femoral a. (thigh)
        
        popliteal a. (knee region)
        
        posterior tibial a. (lower leg)
        
        1 more item...
        
        anterior tibial a.
        
        1 more item...
    - - coronary sinus (cardiac veins)
        
        cardiac veins (caps of myocardium)
      - hepatic vein (drains hepatic portal system)
        
        hepatic portal vein (drains gastric, mesenteric, and splenic veins)
        
        gastric vein (stomach)
        
        mesenteric veins (intestines)
        
        splenic vein (spleen)
        
        these veins do not drain directly into the inferior vena cava. Instead, the blood drained from these abdominal organs travels to the liver via the portal vein.
      - superior vena cava (formed by the union of the left and right brachiocephalic veins = head and upper limbs)
      - great saphenous vein = the longest vein in the body. extends from the medial ankle to the external iliac vein
      - inferior vena cava (drains veins from abdominal and lower limbs)
      - note that there are 2 brachiocephalic veins. The union of the subclavian and jugular veins on each side forms them
      - median cubital vein (venipuncture site)
      - azygous system - azygous vein (right) and hemiazygous (left)
        
        drain intercostal veins and lumbar veins
      - jugular veins (head)
        
        external jugular vein (face and scalp)
        
        internal jugular vein (brain)
- - - - short-term
        
        blood donation 500 ml 10%
        
        vasomotor enough to restore pressure and flow
        
        venous reserve (vasoconstriction)
        
        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, and increase thirst
        
        EPO
      - shock
        
        Acute circulatory crisis
        
        pale, cool, and moist skin
        
        confusion and disorientation (no blood to brain)
        
        hypotension
        
        rapid and weak pulse
        
        no urine
        
        drop in blood pH
    - - extensive vasodilation
        
        capillary flow icnreases
        
        peripheral resistance drops
      - venous return increases
        
        skeletal muscle contractions
        
        increased respiration rate (respiratory pump)
      - cardiac output increases
        
        Frank Starling principle (ventricle pump)
        
        Bainbridge reflex (atrial reflex)
- - - - permit the exchange of gases, nutrients, and wastes between blood and tissues
      - connect arterioles to venules
      - are composed of only a single layer of endothelium and basement membrane
      - capillary arrangement varies by tissue supplied
        
        higher cellular needs (brain, muscle) = more elaborate network
        
        lower cellular needs = less branching
      - regulation of capillary blood flow
        
        smooth muscles control blood entry into capillary beds
        
        metabolic need controls precapillary sphincter
    - - Diffusion
        
        most common
        
        substances include oxygen, CO2, glucose, and hormones
        
        lipid-soluble substances pass directly through endothelial cell membrane
        
        water-soluble substances must pass through gaps between endothelial cells
      - Vesicular Transport (endo/exocytosis)
      - Bulk Flow
        
        Filtration
        
        net affect is fluid loos at the beginning of capillary bed but most is regained by the end of the capillary bed
        
        fluid not regained enters lymphatic vessels
        
        Colloid Osmotic pressure (osmosis) draws fluid back into capillary
        
        Hydrostatic (blood) pressure pushes small solutes and fluid out of capillary
    - - very small arteries
      - deliver blood to capillaries in tissues
      - play a mjor role in regulating blood flow to capillaries, and therefore regulate blood pressure
        
        vasoconstriction (contraction) = decrease vessel volume = decreased blood flow = increased blood pressure
        
        vasodilation = increases vessel volume = increased blood flow = decreased blood pressure
    - - venules and veins carry blood toward the heart
      - venules composed of a tunica externa and a tunica media
        
        extend from capillaries and marge together to form veins
      - thin walled vessels with 3 tunics
      - carry blood under low pressure
      - contains valves in medium sized veins and in the limbs
      - carry blood that is high in carbon dioxide and low in oxygen, except the pulmonary veins
      - veins are large and therefore serve as a blood reservoir, especially in the skin
    - - carry blood that is high in oxygen and low in carbon dioxide, except the pulmonary arteries
      - branch and give rise to thinner vessels called arterioles
      - carry blood that is under great pressure
      - may unite with branches of other arteries supplying the same region forming anastomoses
      - walls have three distinct layers
        
        tunica interna (intima) surrounds lumen
        
        an internal elastic lamina
        
        a basement membrane
        
        a layer of endothelium (simple squamous epithelium)
        
        tunica media is the thickest layer
        
        smooth muscle cells
        
        elastic fibers
        
        tunica externa is the outermost layer
        
        elastic fibers
        
        collagen fibers
      - strong and thick-walled vessels
    - - 60-70% in systemic veins and venules
      - 10-12% in arteries and arterioles
      - 10-12% in pulmonary vessels
      - 8-11% in heart
      - 4-5% in systemic capillaries