BPK 205 ALL

how is pressure lost from friction

friction within the blood, friction between blood and vessel walls

Flow

directly proportional to the pressure gradient and inversely proportional to resistance (Cardiac output)

what is blood flow through the circulatory system driven by

the pressure gradient which is generated by cardiac contraction

venous return (VR)

the flow of blood into the right atrium from the peripheral vessels

where is blood flow velocity slowest

capillaries, total cross-sectional area is large

precapillary schincters

open and close in response to local metabolic conditions

metarterioles

divert blood flow if sphincters are closed, also allow larger materials (WBC) to bypass narrow capillaries

capillaries

site of gas exchange, are leaky, density related to metabolic activity of cells, single layer of flattened epithelial cells

bulk fluid flow

3L/day of fluid through capillaries, excess picked up by lymphatic vessels

active hyperemia

increased blood flow accompanies increased metabolic activity

reactive hyperemia

increased tissue blood flow following period of low perfusion

orthostatic hypotension

decreased blood pressure that occurs upon standing up

Atherosclerosis

inflammatory condition in which fatty deposits called plaques develop in arteries

what are the pressure resevoir

arteries, are elastic and can stretch and recoil to maintain pressure

systemic pressure

highest in aorta; declines throughout pathway; 0 mm Hg in right atrium

pulse pressure

systolic pressure minus diastolic pressure (avg. 40mm Hg) force heart creates each contraction

Mean Artieral Pressure (MAP)

diastolic pressure + 1/3 (pulse pressure) = avg. 60mm Hg (driving pressure)

HR x SV =

CO

EDV - ESV =

SV

CO x R =

MAP (~93) min 60

how to quickly decrease BP

compensation by cardiovascular system (vasodilation, decrease CO)

how to slowly decrease BP

compensation by kidneys (excretion of fluid in urine decreases blood volume)

arteriole resistance by changing radius

local factors (myogenic or paracrine response, sympathetic NS regulation

local factors: myogenic autoregulation

reflexive constriction helps maintain constant blood flow despite changes in perfusion pressure

local factors: paracrines

active hyperemia will cause vasodilation (O2,CO2, H+), reactive hyperemia compensation after reduced blood flow

SNS effect: norepinephrine

a1-adrenergic receptors, increase constricts, decrease dilates, diverging mechanism

what type of control does SNS effect on arteriole resistance

tonic control on most arterioles

SNS effect: epinephrine

released from adrenal medulla, fight or flight, b2-adrenergic receptors, converging mechanism

Baroreceptors

pressure sensors in carotid and aortic arch, stretch-activated, tonically active, increased pressure opens more channels=more AP

Baroreceptor reflex

The primary reflex pathway for homeostatic control of blood pressure (decrease sympathetic output, increase parasympathetic output)

plasma proteins

albumins, globulins, fibrinogen

cellular elements of blood

erythrocytes (RBC), leukocytes (WBC), platelets (thrombocytes)

5 WBC

lymphocytes, monocytes, neutrophils, eosinophils, basophils

fibrinolysis

Plasmin dissolves fibrin in platelet plug + breaks down clot as damaged vessel is repaired

Prostacyclin

restricts platelet plugs to site of injury

anticoagulants

limit extent of blood clotting within a vessel

blood

7% of body weight, connective tissue, watery extracellular matrix (plasma 1/4 body ECF)

centrifugation

Separates components by density using high speed spinning

buffy layer

platelets and white cells between plasma and RBCs ~1%

hematocrit

% of total blood volume that is occupied by RBC ~42%

hematopoeisis

synthesis of blood cells occurs in the red bone marrow of long flat bones, 25% become RBC, 75% become WBC

cytokines

proteins release from 1 cell that affect the activity of another

Erythropoietin (EPO)

low RBC, produced in kidney cells

Thrombopoietin (TPO)

low platelets, produced in liver

hypoxia

low O2 levels in arterial blood, sensed by kidney stimulates EPO

hemoglobin

four protein globin chain, centered around a porphyrin heme group ring, iron atom in center

enemia

low RBC count, decreased hemoglobin content=reduced O2 carrying capacity

hemolytic anemia

accelerated RBC loss, genetic (sickle cell), acquired (malaria)

aplastic anemia

decreased RBC production, from drugs or radiation, dietary insufficiencies

hemorrhage

loss of blood from the vessels

hemostasis

keeping blood inside the blood vessels

4 steps to hemostasis in response to damage

vasoconstriction, platelet plug formation, coagulation, dissolution of clot

the coagulation cascade

The series of steps beginning with the intrinsic (collagen) or extrinsic (tissue factor) pathways of coagulation and proceeding through the formation of a fibrin clot

Fibrinolysis

tissue is repaired and clot dissolves due to actions of enzyme plasmin

A+ blood type

A flag, + Rh

A- blood type

A flag, no Rh

universal acceptor

AB (Rh+)

universal donor

O (Rh-)

hemolytic disease of the newborn

anti-Rh antibodies will cross the placenta and damage fetal RBC

air flow

nasal cavity, pharynx, larynx, trachea, primary bronchi, smaller bronchi, bronchioles, alveoli

functions of respiratory system

gas exchange, regulation of pH, conditioning inspired air, protection, vocalization

inspiration

air moves into lungs

expiration

air moves out of lungs

ventilation

air in and out

pleural membranes

fluid filled balloon that wraps around lungs so ribs and lungs move together

cardiac notch

A concave space on the left lung in which the heart lies

muscles used for quiet breathing

external intercostals, diaphram

muscles used for forceful breathing

sternocleidomastoids, scalenes

muscles used for forceful exhalation

internal intercostals, abdominal muscles

visceral pleural membrane

surrounds the lungs

parietal pleural membrane

surrounds intrapleural fluid and attaches to chest wall

pleural sac

protects lungs, lubricated membranes to slide, sticks lungs to thoracic wall, keeps lungs inflated

main role of airways

filter out foreign substances, warm air, add water vapor

watery saline layer of respiratory tract

allows cilia to push mucus toward pharynx (cystic fibrosis missing this layer)

bronchodilation

decreased resistance, paracrine response to CO2, SNS response nore/epinephrine bind to B2-receptor, Gs pathway

bronchoconstriction

increased resistance, paracrine response to histamine, PNS response ACh binds to (M3) muscarinic receptors, Gq pathway

alveoli

site of gas exchange, make up most of lung tissure, one layer epitheliaal cells,

type 1 alveolar cells

gas exchange, 95% alveolar space, squamous

type 2 alveolar cells

make and secrete surfactant

Surfactant

fluid that lines all the alveoli making them easier to expand and prevent from collapsing, decreases SA and tension

transpulmonary pressure

force inflating the lungs (Palv - Pip = 4mm Hg)

Functional Residual Capacity (FRC)

volume of air remaining in the lungs after a normal tidal volume expiration (ERV + RV)

pneumothorax

air in the pleural cavity caused by a puncture of the lung or chest wall

compliance

ability of the lung to stretch, decreased in restrictive pulmonary disease (fibrosis-espestos)

elastance

ability of the lung to spring back after being stretched, decreased in emphysema, loss of elastin

boyle's Law

P1V1 = P2V2

what does air sucked in do

lung volume increases, pressure in lungs decrease, inspiratory muscles contract

what does blowing air out do

lung volume decreases, pressure inside lungs increase, inspiratory muscles relax

spirometry

to measure changes in lung volumes during ventilation

tidal volume (Vt)

normal in and out ~500ml

Inspiratory reserve volume (IRV)

can pull in but usually dont

Expiratory Reserve Volume (ERV)

can push out but usually dont

Residual Volume (RV)

cant push out-lungs are inflated

inspiratory capacity

Vt + IRV, total capacity

Vital Capacity (VC)

TV + IRV + ERV, normal working range

Total Lung Capacity (TLC)

Vt + IRV + ERV + RV, everything

Dalton's law

Total pressure exerted by a mixture of gases is the sum of pressures exerted by all individual gases

what is rate of diffusion directly proportional to

SA, membrane permeability (D), conc. gradient

what is rate of diffusion inversely proportional to

diffusion distance (membrane thickness, interstitial fluid)

Hemoglobin

Found in RBC, reversibly binds to 4 O2, increases blood O2 carrying capacity, HbO2=oxyhemoglobin