pressure in vena cava= 0 mm Hg

pressure in aorta= 85 mm Hg 

arteries>arterioles>capillaries>venules>veins

Systemic circuit has greater pressure than pulmonary

Radius of vessels (in arterioles and small arteries can be regulated)

Length of vessel

Viscosity of fluid

Flow = DP r4

           8 h L

poiseuille's law= resistance 

therefore plug it into the flow equation 

expanding pressure due to increased volume in arteries

max pressure

due to ejection of blood into aorta 

elastic recoil in arteries 

Minimum pressure

-not zero due to elastic recoil

carbon dioxide

potassium

hydrogen ions

increased blood flow in response to a previous reduction in blood flow

increased resistance; decreased blood flow

the effect of: oxygen, potassium ions in HIGH concentration, and endothelin-1

stretching out of smooth muscle in vessel walls; decreased resistance and therefore increased blood flow

effect of:

carbon dioxide

potassium ions

acids (hydrogen ions)

adenosine

nitric oxide 

Flow = changeP/R; CO = MAP / TPR; MAP = CO x TPR

ØMean arterial pressure depends on TPR

Sympathetic activity and hormones are used to regulate this

Sympathetic nerves(vasoconstriction)

epinephrine( Alpha: vasoconstriction beta:vasodialation)

vasopressin(vasoconstriction) 

*site of exchange

*1mm long and 5-10 um diameter

*most cells found within 1 mm of a capillary

*one cell layers to produce a small diffusion barrier

*blood velocity though capillaries is slow(enhances exchange)

*cappilaries have the greatest total cross section areaal 

*most common

*found in small gaps between endotherlial cells

* allows small water soluble molecules to move through 

*found in large gaps between endothelial cells and forming pores or fenestrations

*allow protiens and in some cases blood cells to move through

drive movement of fluid into and out of capillaries

*capillary hydrostatic pressure(pressure inside cappilary)FILTRATION PRESSURE

*intersitital hydrostatic pressure (pressure of fluid outside capillary)Absorbtion pressure

*capillary osmotic pressure(due to presence of nonpermeating solutes in cappilary)Absorbtion pressure

*interstital fluid osmotic pressure (due to presence of nonpermeating solutes outside of capillary)FILTRATION PRESSURE

filtration or absorbtion

used to distribute extracellular fluid

arteriole end: filtration is favored

venule end: absorbtion is favored

three liters per day 

*lymphatic system picks up excess filtrate and returns it into circulation

-expand with little changes in pressure

-function as blood reservoir (vessel compliance)

-60% of blood volume in systemic veins at rest

-one way valves in peripheral veins 

inspiration- decreased pressure in thoracic cavity and increased pressure in abdominal cavity

This pressure moves blood to thoracic cavity and increases centeral venous pressure and increases venous return

increased blood volume=increased venous pressure

-smooth muscle tension in walls of veins (innervated by sympathetic nervous system)

-alpha adrenergic receptor

-üNorepinephrine stimulates contraction of smooth muscle causing venous constriction

-increases venous return

-decreases venous compliance 

-heart rate*stroke volume* total peripheral resistance 

-regulated neurally and hormonally

-baroreceptors located in the aortic arch and the carotid sinuses- strategically places to detect any decrease or increase in MAP

-short term regulation: primary meural control (heart and blood vessels involved)

-long term: inloves kidneys and hormones control to regulate blood volume 

plasma: 55%

erythrocytes: 45%

leukocytes and platelets< 1% of blood volume 

fractional contribution of erythrocytes in blood

Females: 37-47

males: 42-52

-90%water

- 6-8% protiens

-high concentrations of sodium and chloride 

-low concentrations of hydrogen ions, hydrogen carbonate and potassium and calcium 

wastes: urea, bilirubin, and creatinine

-hormones

-O2 and CO2

plasma protiens

(synthesized in the liver except some globulins are synthesized by lymphocytes)

Albumins(60%)

-oncotic pressure- carriers

Globulins (36%)

-carriers, clotting factors, enzymes, precursor protiens (angiotensinogen)- part on immune system 

Fibrinogen- blood clotting

Erythrocytes

transport oxygen and carbon dioxide

5 billion per ml of blood

biconcave shape to create larger surface area and favor diffusion

8mm diameter and 2mm thick

no nucleus or organelles (no mitochondria only anaerobic glycolysis)

FLEXIBLE MEMBRANE

Spectrin - fibrous protien in cytosol

hemoglobin- carries the oxygen

enzymes

-glycolytic enzymes

-carbonic anhydrase (catalyzes reaction from CO2 to H2CO3)

Globin+ 4 heme groups 

globin is 4 chains of peptides

heme is an iron containing group

98.5% of O2 is transported via hemoglobin

(the rest is dissolved in the plasma) 

Erythrocye life cycle

(do not divide)

(no dna rna or organelles)

200 billion are produced every day

life span of only 120 days 

synthesized in the red bone marrow- erythropoiesis

Spleen filters them out of blood for catabolic 

Same stem cells in bone marrow- hematopoietic stem cells

erythrocyte synthesis is stimulated by erythropoietin with is secreted from the kidneys when oxygen levels to the kidneys drop

Decrease in the oxygen carrying capacity of blood

-dietary anemia:

*iron deficiency anemia (cause by lack of iron)

*Pernicious anemia (caused by lack of B12)

Hemorrhagic anemia (caused by bleeding) 

white blood cells

4000 to 10000 per cubic mm

five different types each with a role in immunity: neutrophils, eosinophils, basophils, monocytes, and lymphocytes 

neutrophils, eosinophils, and basophils

contain cytoplasmic granules that are protien carrying vesicles

50-80% of all wbc

one of the most important defense activities 

phagocyte: engulfs and digests microorganisms and sbnormal cells

-circulate in blood for 7-10 hrs then more to tissue where they only live a few days 

1-4% of all leukocytes

phagocyic, BUT their main contribution is by attacking parasitic cells too large to engulf by attaching to them and releasing toxic molecules that are stored in their cytoplasmic granule

**response is weak and may cause an allergic reaction due to the release of the toxins around other tissues

nonphagocytic

less that 1% of leukocytes

release toxins to damage invaders

BUT also release histamine, heparin, and other chemicals that contribute significantly to allergic reation 

2-8% of leukocytes

phagocytic

circulate for a few hours, then go into tissue where they become much larger and become known as macrophages (big eaters) 

20-40% of leukocytes

99% of all cells found in interstitial fluid 

B cells Tcells and Null cells 

mechanisms that stop bleeding

Thrombus- formation of a blood clot

when a blood vessel is damaged intrensic mechanisms trigger a vascular spasm

the sympathetic nervous system is activated as well

AKA thrombocyte

Forms around site of vessel damage

decreases blood loss

necessary for production of a blood clot

conversion of blood into gel that traps erythrocytes to plug damaged vessel 

Called a thrombus

*occurs around platelet plug

DOMINANT HEMOSTATIC DEFENSE MECHANISM

*coagulation cascade leads to fibrin clot

colorless cell fragments- no nucleus BUT there are organelles and granules 

100,000-500,000/ ml of blood

Important in blood clotting

Granules containing ADP, serotonin, epinephrine and chemicals for blood coagulation to be secreted into plasma

Clotting steps

(First steps) 

♥Blood vessel damage

♥exposure to subendothelium

♥vWf binds to collagen fibers

(vWf, von Willebrand factor, is key protien in platelet plug formation)

♥platelets bind to vWf 

platelet adhesion & sticky &  secretions(seritonin & epintphrin)

Clotting steps

(second steps) 

Aggregated platelets release secretory products

ADP- increases stickiness and create positive feedback loop that increases rate of platelet plug formation 

Serotonin and epinephrin- cause vasoconstriction

Chemicals to facilitate blood coagulation are also released

ADP stimulates the production of thromboxane A2 which forms another positive feedback loop, causes vasoconstriction, and stimulates more ADP secretion

♥Fibrinogen

♥Fibrin(Loose)

♥Fibrin(mesh)

(Fibrin clot=Blood clot)

In blood as inactive form and is activated during coagulation cascade

Genetic disorder

deficiency of gene for clotting factor. Most commonly due to deficiency in clotting factor VIII 

requires another cascade initiated by exposure of collagen

♥plasminogen

(plasminogen activators)

♥plasmin

♥plasmin dissolves clot by enzymatically breaking down fibrin

Convert plasminogen to plasmin

EXAMPLE: Tissue Plasminogen Activator (TPA)

-secreted by endothelial cells during clot formation

-activated by fibrin 

In low doses it prevents the formation of thromboxane A2 which decreases platelet aggregation and plug formation.

In high doses it inhibits the formation of prostacyclin which actually increase the probablitiy of clot formation 

IN LOW DOSES asprin reduces the incidence of heart attacks and the severity of damage after heart attack 

*cellular respiration

*refers to the use of oxygen within the mitochondria to generate ATP by oxidative phosphorylation and the production of CO2 waste

exchange of oxygen and carbon dioxide between the atmosphere and body tissues

*involves respirator and circulator systems 

♥ pulmonary ventilation- movement of air into and out of lungs through inspiration and expiration 

♥exchange of O2 and CO2 between lung air spaces and blood via diffusion 

♥transport of O2 and CO2 between lungs and body tissues via the blood

♥exchange of O2 and CO2 between blood and tissues via diffusion 

♥contributes to the acid base balance in blood

♥enables vocalization

♥participates in defence against foreign particles in airways

♥provides route for water and heat loss

♥enhances venous return through respiratory pump

♥activates cetain plasma protiens through pulmonary circulation 

*passages in head and neck

*nasal/ oral cavity which leads to pharynx(muscular tube) then to the larynx

*all passageways leading from the pharynx to the lungs

divided into two zones: conducting zone and the respiratory zone

upper part of the respiratory tract

Trachea>bronchi>secondaty bronchi>tertiary bronchi>bronchiole>terminal bronchioles

*larynx 

*trachea- c-shaped bands of cartilage hold open

*trachea then divides into left and right bronchi in the thoracic cavity

*bronchi divide into seondary bronchi in each lung(three in right two in left)

*secondary into tertiary bronchi then bronchioles then teminal bronchioles-smallest compnent of conducting zone

Being an air passageway is the promary function of the conduction zone

♥150ml of air is held in this zone and is considered "dead space" due to the fact that it does not participate in gas exchange with blood

♥Tempurature of air is increased through this space and humidified to keep resitory tract moist

♥Respiratory bronchioles

♥Alveolar ducts(where bronchioles terminate)

♥Aveoli (where gas exchange occurs)

*single layer of epithelial cell ,type I alveolar cells, over basement membrane  

♥aveolar sacs(clusters of aveoli)

primary function is to exchange gases between air and blood

This is done via diffusion 

terminal bronchioles turn into respiratory bronchioles. 

ALveolar clusters are known as alveolar sacs are found at the end of alveolar ducts

wall of alveolus cross section

Type I cells- make up structure of wall

Type II cells- secrete surfactant 

Alveolar macrophages which engulf foreign particles enhaled into lungs 

D) shows close assosiation between capilary walls and aveolar walls

plural sac attached to the lungs is known as the visceral pleura

plural sac attached to chest wall is known as the parietal plura

Pressure gradient drives flow

air moves from high to low pressure 

inspiration-pressure in lungs is less than atmosphere

expiration-pressure in lungs is greater than atmosphere

Atmospheric pressure= Patm (760 mmHG at sea level)

Intra-alveolar pressure= Palv

Pressure of air in alveoli

Intrapleural pressure= PIP

Pressure inside pleural sac

Transpulmonary pressure=Palv - PIP

Distending pressure across lung wall 

pleural sac is broken and neg intrapleural pressure is lost; lung recoils and collapses while the chest recoils and explands

*Spontaneous pneumothorax occurs if disease damages wall 

*Tramatic Pneumothorax occurs if trauma pierces sac

Force fore flow is the pressure gradient

Atmospheric pressure is constant during breathing cycle; therefore, changes in alveolar pressure creates changes in pressure gradients

Boyle's Law

[image]

Any given quantity of gas in an airtight container Pressure is inversly related to volume 

*Pressure changes in lungs occur due to volume changes

During inspiration the expantion of the lungs causes intra-aveolar pressure to decrease

The intake of air raises the pressure to equal that of the atmosphere

During expiration the collapsing of the lungs causes the pressure to be greater than that of the atmophere and therefore, causes the air to travel back down the pressure gradient and out of the lungs 

inspiration- external intercostal muscles and diaphragm contract; chest walls and lungs expand

Expiration- external intercostals and diaphragm relax;chest cavity and lungs contract

internal intercostals and abdominals contract for active expiration

Ease with which lungs can be stretched

(change in volume)/(the change in alveolar pressure minus intrapleural pressure)

Larger lung compliance

-easier to inspire

-smaller chane in transpulmonary pressure needed to bring in given volume of air

Elasticity

-more elastic= less compliant

Surface tension, measure of work required to increase surface area, (caused by air/liquid interface) of lungs

-greater tension-less compliant 

Type II cells secrete surfactant-a detergent that decreases surface tension 

-makes inspiration easier by increasing lung compliance and decreasing work of breathing

Autonomic nervous system

Sympathetic stimulation and the release of epinephrine (hormonal control):

-relaxation of smooth muscle causing bronchodialation

Parasympathetic:

-contraction of smooth muscle causing bronchoconstriction

Histamine (bronchoconstriction): released during asthma and allergies. ALSO causes an increase in mucus secretion which builds up in airways

Carbon dioxide- bronchodialation

Oxygen- bronchoconstriction 

In pulmonary  capillary bed oxygen diffuses from alveoli to blood and CO2 diffuses from blood into alveoli

In Systemic Capillary beds oxygen diffuses from blood into cells and CO2 diffuses from cells into blood

-79% Nitrogen

-21% Oxygen

*trace amounts of CO2, helium, argon, ect. 

*if humid, H2O can be a factor

♥They diffuse from high pressure to low pressure(down pressure gradients)

♥In mixtures, they diffuse down partial pressure gradients (high partial pressure to low partial pressure)

♥Presence of oter gases is irrelevant, gas will diffuse down its own partial pressure gradient 

1) the partial pressures of inspired air

2) minute aveolar ventilation(the volume of fresh air reaching the aveoli each minute)

3)Rates at which tissues are consuming O2 and producing CO2*** MOST CRITICAL 

increase ventilation due to increased metabolic demands of the body

♥minimal changes in partial pressures of O2 and CO2

ventilation does not meet demands

O2 decreases and CO2 increases

Ventilation is increased as a response by chemoreceptors

ventilation exceeds demands

Partial pressure of O2 increases and CO2 decreases 

ventilation is decreased as a response by chemoreceptors

transported mostly via hemoglobin

*1.5% or 3ml/200ml is dissolved in the plasma

-completely saturated 1 gram of hemoglobin carries 1.35 mL O2

Normal blood hemoglobin levels 12-17 gm/dL

200mL O2/ liter of blood

Arterial blood is 98.5% saturated with O2

Venous bloos is 75% saturated with O2

Higher temp: decreases the affinity of hemoglobin for oxygen (shift right)

-more O2 unloading and more O2 delivery to tissues

Bohr effect

(Lower pH, more acidic, increases O2 unloading)

Carbon dioxide reacts with hemoglobin to produce carbaminohemoglobim.

It has a lower affinity for oxygen that hemoglobin.

It increases metabolic activity and therefore increases CO2 produced. 

O2 unloading in active tissue is also increased. 

5-6% dissolves in plasma

5-8% transported via hemoglobin

86-90% is converted to bicarbonate by erythrocytes and transported in the plasma

Inspiratory neurons: depolarize during inspiration

expiratory neurons- depolarize during expiration

mixed neurons- have properties of both 

Chemoreceptors

Pulmonary stratch receptors

Irritant receptors

Muscle and joint proprioceptors

Chemically sensitive receptor cells

 Detect blood O2 and CO2 levels

 peripheral chemoreceptors-in carotid body respond to changed in Po2, Pco2, and pH

Central chemoreceptors- in medulla oblongata and respond directly to changes in thehydrogen ion concentration in cerebrospinal fluid surrounding this area

Centeral chemoreceptors respond best to changes in pH

H+ ions can not cross blood brain barrier instead bicarbonate is produced 

Decrease in PO2 activates the peripheral chemoreceptors but not centeral chemoreceptors. 

And increase in PCO2 decreases the pH by producing more H+ ions and both chemoreceptors detect and respond by increasing ventilation 

Ventilation: rate of air flow (VA)

Perfusion: rate of blood flow (Q)

Local ventilation and perfusion are regulated to match

If ratio is less than one (obstructed airway) then PCO2 increases and PO2 decreases

If ratio is greater than one (obstructed blood vessel) then PO2 increases and PCO2 decreases

pH balance

normal= 7.4 (7.3-7.42)

Respiratory and renal systems regulate blood pH

(small changes in pH have BIG physiological effects such as alter protien activity)

Acidosis: blood pH is less than 7.35; causes CNS depression(coma or death) cause by increase [CO2]

Alkalosis: pH is greater than 7.45 causes CNS over-excitation(muscle seizures and convulsions) cause by decrease in [CO2]

Hemoglobin acts as a buffer

-deoxyhemoglobin has greater H+ affinity

Bicarbonate ions act as buffer and can regulate pH by regulating CO2 levels

Henderson Hasselbalch equation 

                          [HCO3–]

pH = 6.1 + log

                             [CO2]

Bicacarbonate:carbondioxide MUST= 20:1

Respiratory regulates [CO2]

Kidneys regulate [HCO3-]

♥Plasma ionic composition

♥plasma volume

♥plasma osmolarity(solute concentration)

♥plasma pH

♥Secrete erythropoietin

♥secrete renin

♥activate vitamin D3 to calcitriol

♥gluconeogenesis

♥remove metabolic waste and foreign sub from plasma

Structures of the urinary system 

♥two kidneys

♥two ureters

♥the urinary bladder

♥the urethra

renal pyramid containing nephrons (functional units of kidney)

Nephrons are composed of renal tubule that fluid flows through and is modified with interstitial fluid. the fluid is then drained into the nephrons collecting ducts and is then urine.

renal corpuscle is composed of Bowman's capsule and the glomerulus(tuft of capillaries).

BLood into glomerulus through afferent arteriole then into Bowman's Capsule and out via efferent arteriole. 

Proximal tubule>The loop of Henle: the portion of the tubule that makes up the hairpin loop within medulla>distal tubule

Cortical nephrons: majority of nephrons in the kideys; located almost entirely in the renal cortex; only tip of loop of henle dips into medulla

Juxtamedullary nephrons: 15-20% of nephrons; renal corpuscle is located near the medulla and cortex boarder; loop of henle dips deep into the medulla; helps maintain an osmotic gradient

plays huge role in regulating blood volume and pressure

two components

1)specialized cluster of the tubule's epithelial cells(macula densa)

2)granular cells that are in the wall of the afferent arterioles and have granular cytoplasms

peritubular capillaries located around renal tubules

vasa recta located around the loop of henle

Filtration occurs in the renal corpuscle and is the bulk flow of plasma free protiends from the glomerulus to bowmans capsule.

Reabsorbtion takes place along the tubules and is the movement of water or solute from the lumen of the tubules into the peritubular capillaries.

Secretion is the movement of water or solute from the peritubular capillaries into the lumen of the lubules.

quantity filtered 

=glomerular filtration rate × plasma concentration of X

depends on plasma concentration of solute and GFR

Small molecules that are filtered without impedance are freely filterable

Intrensic regulation of Glomular filtration rate

Smooth muscle in wall of afferent arteriole

-contracts in responce to stretch 

the volume of plasma filtered per unit of time

approx. 125ml/min

one day 180 liters filtered

Macula densa cells (specialized cluster of tubules epithelial cells) secrete paracrine in response to an increase in fluid past them

Smooth muscles of arteriole contract in response to this paracrine

Decrease in BP decreases GFR

-directly by decreasing the filtration pressure

-indirectly through extrensic controls

Movement from tubules into peritubular capillaries and returned to blood

-mostly occurs in the proximal tubule

-most is not regulated

Transport: active transport, passive diffusion, water via osmosis

-mostly occurs in proximal convoluted tubule

-some in distal conv. tubule

BARRIER FOR REABSORBTION: epithelial cells of renal tubules and endothelial cells of capillary

Counter current multiplier (19)

Establishes osmotic gradient

-dependent on look of henle

Ascending limb: impermiable to H2O; active transport of sodium, chloride and potassium

Descending limb: permiable to H2O, no transport of ions

Plasma concentration of solute at which "spillover" into the urine occurs

Transport max: reached when solute transported across epithelium by carrier protien saturates the carrier

for a solute that is normally 100% reabsorbed

-if solute filtrate saturates carriers then some solute is excreted in urine

-

Used to estime GFR

By-product of muscle metabolism

-small amount secreted

Clearance a little greater than GFR 140 ml/min