HSF etest2

components of cardiovascular system

heart, blood vessels, blood

functions of cardiovascular system

transporting oxygen and nutrients, protection, regulation

function of heart

pump blood, route blood between pulmonary and systemic circulation, one way flow, regulate blood supply

protection of the heart

protected by ribcage, protective membranes, fluids

location of heart

in mediastinum and thoracic cavity, medial to lungs, superior to diaphragm

shape of heart

blunt cone, rounded end is apex which is inferiorly and anteriorly pointed, broader end is base, which is posteriorly and slightly superior

fibrous pericardium

tough outer layer that protects the heart and anchors it to surrounding structures. prevents over distension

serous pericardium

the inner layer of the pericardium that consists of two layers (parietal and visceral) and secretes serous fluid for lubrication. simple squamous epithelium. they are continuous and have a pericardial cavity filled with pericardial fluid

anterior side of heart

large blood vessels and depressions

posterior side of heart

small blood vessels and atrial wall

coronary sulcus

grooves on the heart’s surface that separate atrium and ventricle

anterior and posterior interventricular sulci

grooves that separates right and left ventricles

pericardial fat

fatty tissue between visceral and parietal pericardium

epicardial fat

between outer layer of myocardium and visceral layer of pericardium

atria

superior chambers of the heart that collects blood. thin walls.

ventricles

inferior chambers of the heart that discharge blood. thick walls.

epicardium

serous membrane, simple squamous epithelium over areolar tissue, smooth outer surface of heart. visceral pericardium

myocardium

middle layer, thickest, composed of cardiac muscle cells that allow the heart to contract

endocardium

smooth inner surface of heart chambers, simple squamous epithelium over areolar tissue, covers valve surface and continuous with endothelium

interventricular septum

muscular wall separating the left and right ventricles of the heart.

interatrial septum

muscular wall that separates the left and right atria of the heart. contains the fossa ovalis- a depression

which ventricle wall is thicker?

pectinate muscles

muscular ridges located in the walls of the atria, helping to increase the contractile strength of the atrial walls.

trabeculae carnae

muscular ridges found in the ventricular walls of the heart, contributing to the strength and function of the ventricles. create turbulence in blood

right atrium

thin walled, mostly on posterior side. receives deoxygenated blood returning from superior and inferior vena cavae and coronary sinus

right ventricle

pumping chamber, mostly on anterior side, thicker walled than atria. receives deoxygenated blood from right atrium, opens to pulmonary trunk, contains trabeculae carnae.

left atrium

thin walled chamber that receives oxygenated blood returning from lungs through four pulmonary veins

left ventricle

pumping chamber, thickest walled chamber, receives oxygenated blood from left atrium, opens to aorta, contains trabeculae carnae

vessels into right atrium

superior and inferior vena cavae (systemic), coronary sinus (coronary)

vessels into left atrium

four pulmonary veins (pulmonary)

vessels out of right ventricle

pulmonary trunk (pulmonary)

vessels out of left ventricle

aorta (systemic)

atrioventricular valves

valves located between the atria and ventricles, including the tricuspid (right) and bicuspid (left) valves, that allow blood flow from the atria to the ventricles while preventing backflow. cusps attached to papillary muscles by chordae tendineae. when valve is open, blood flows from atrium to ventricle, when closed blood exits ventricle

semilunar valves

valves located at the exit of the ventricles, specifically the pulmonary valve (right) and aortic valve (left), that prevent backflow into the ventricles after contraction.

function of heart valves

prevent backflow of blood. open and close due to changes in blood pressure within the heart chambers

function of chordae tendineae

strings connecting valve cusps to papillary muscles, prevent AV valves from bulging into atria

function of papillary muscles

pillar-like muscles in ventricles that prevent prolapse of AV valves

blood flow of heart

superior and inferior vena cava, right atrium, tricuspid valve, right ventricle, pulmonary semilunar valve, pulmonary trunk, pulmonary arteries, lung (pulmonary circulation), pulmonary veins, left atrium, bicuspid valve, left ventricle, aortic semilunar valve, aorta, body (systemic), heart (coronary)

pulmonary circulation

deoxygenated blood is transported to lungs for oxygenation and then returned to heart. deoxygenated blood enters right atrium and ventricle then exits through pulmonary trunk to pulmonary arteries for oxygenation. oxygenated blood travels in pulmonary veins and enters left atrium

systemic circulation

oxygenated blood is transported to body tissues then returned to heart. oxygenated blood enters left atrium and ventricle. left ventricle contracts and pushes blood out through aorta. deoxygenated blood travels back to heart and re-enters right atrium through vena cava

coronary circulation

part of systemic circulation that supplies only heart

cardiac output

amount of blood ejected out of heart/min. heart rate X stroke volume

action potential

a rapid change in membrane potential. acts as an electrical signal/impulse. spread through the conducting system to all cardiac muscle cells, causing cells to contract and pump blood. heart can generate its own action potentials

cardiac conducting system

internal pacemaker and nerve like pathway through myocardium

auto-rhythmicity

repetitive contractions caused by autorhythmic contractile cells

step 1 of conducting system

action potentials originate in the sinoatrial (SA) node and travel across the atrium wall from the SA node to the AV node

step 2 of conducting system

action potentials pass through the AV node and along the AV bundle which extends from the AV node, through the fibrous skeleton into the interventricular system

step 3 of conducting system

the AV bundle divides into right and left bundle branches and action potentials descent to the apex of each ventricle along the bundle branches

step 4 of conducting system

action potentials are carried by the Purkinje fibers from the bundle branches to the ventricular walls and papillary muscles

composition of blood

55% plasma, 45% formed elements (RBC, WBC, platelets)

erythrocytes

red blood cells that contain haemoglobin and carries oxygen from lungs to tissues and carbon dioxide from tissues to lungs

leukocytes

white blood cells that help in protection. various types include neutrophils, lymphocytes, monocytes, eosinphils and basophils.

arteries

take blood away from heart, contain blood under pressure. deep in muscle, no valves, round lumen, hold shape

capillaries

site of exchange with tissues (interstitial fluid)

veins

take blood to the heart, blood not under pressure, thinner walls than arteries, contain less elastic tissue less smooth muscle. closer to surface of body, contain valves, flat lumen, look collapsed

tunica intima

endothelium, basement membrane, lamina propria, elastic tissue

tunica media

smooth muscle cells and elastin arranged circularly. smooth muscle changes diameter of lumen. elastic tissue allows distension and recoil. vasoconstriction and vasodilation.

tunica externa

connective tissue, transitions from dense to loose CT as it merges with surrounding tissue

continuous capillaries

no gaps between endothelial cells, less permeable to large molecules than other capillary types eg muscle, nervous tissue

fenestrated capillaries

pores in endothelial cells called fenestrae, highly permeable. eg intestinal villi, glomeruli of kidney

sinusoidal capillaries

large diameter, irregular incomplete wall of endothelial cells, less basement membrane eg endocrine glands, liver

capillary exchange

the process by which nutrients, gases, and wastes are exchanged between blood and tissues through capillary walls.

gross anatomy of renal system

2 kidneys, 2 ureters, urinary bladder, urethra

location of kidneys

posterior to parietal peritoneum on posterior abdominal wall. partially protected by lumbar vertebrae and ribs

renal capsule

connective tissue surrounding each kidney

adipose tissue

surrounds the outside of the capsule for protection

renal fascia

thin layer of connective tissue surrounds the adipose tissue, anchor kidneys to abdominal wall

hilum

on the concave (medial) side. renal artery and nerves enter. renal vein, ureter and lymphatics exit. opens into renal sinus

renal sinus

filled with fat and loose CT.

renal pyramids

bases project into cortex. cone shaped. base is boundary between cortex and medulla.

renal columns

extensions of cortical tissue into medulla

renal papilla

apex of pyramid. papillae extend into minor calcyes

minor calyces

funnel-shaped chambers that funnel into major calyces

renal pelvis

single large funnel-shaped chamber that is embedded in the renal sinus. it narrows at the hilum to form the ureter

nephron

functional unit of the kidney. composed of 4 regions- renal corpuscle, proximal convoluted tubule, loop of Henle, distal convoluted tubule. blood enters the nephron for filtration. filtrate/urine is produced.

urine flow

nephron, papillary ducts, minor calyces, major calyces, renal pelvis, ureter

number of nephrons

approximately 1.3 million nephrons in each kidney.

juxtamedullary nephrons

renal corpuscle is deep in cortex near medulla. long loop of Henle extending deep into medulla. 15% of nephrons

cortical nephrons

renal corpuscle located near the periphery/cortex. shorter loop of Henle. 85% of nephrons

renal corpuscle

filtration portion of nephron. consists of glomerulus and bowman capsule.

glomerulus

network/ball of capillaries. blood enters through afferent arteriole, filtered blood exits through efferent arteriole.

bowman capsule

enlarged end of nephron, double walled chamber. filters blood/fluid, which enters the proximal convoluted tubule. parietal layer is simple squamous epithelium that becomes cuboidal in PCT. visceral layer is constructed of podocytes that wrap around the glomerular capillaries.

filtration membrane

a barrier between the blood in the glomerulus and the inside of the Bowman capsule, composed of fenestrated epithelial cells, podocytes, and a basement membrane that allows water and small solutes to pass while restricting larger molecules.

proximal convoluted tubule

filtrate drains into PCT from the bowman capsule. simple cuboidal epithelium with microvilli and mitochondria. active reabsorption of Na, K and Cl-

loop of Henle

descending and ascending limb. thick parts of simple cuboidal epithelium. thin parts simple squamous epithelium for osmosis and diffusion

distal convoluted tubule

shorter than PCT. simple cuboidal with few microvilli. many mitochondria and active reabsorption

collecting duct

several DCTs connect to a single collecting duct. large diameter. extends through medulla toward renal papilla to ureter. simple cuboisal epithelium

major renal veins and arteries

abdominal aorta, right and left renal artery, right and left renal vein, inferior vena cava

urine movement

pressure forces urine through nephron. smooth muscle forces urine through ureters. peristalsis moves urine from renal pelvis in the kidneys, ureters, urinary bladder. ureters enter bladder obliquely through trigone. pressure in bladder compresses ureter and prevents backflow.

parasympathetic stimulation increases frequency

sympathetic stimulation decreases frequency

ureters

passageway for urine from renal pelvis to urinary bladder. transitional epithelium.

urinary bladder

hollow muscular container located in pelvic cavity posterior to symphysis pubis.

trigone

triangular area on posterior wall between the entry of the two ureters and the exit of the urethra

urethra

transports urine from the urinary bladder to the outside of the body. transitional epithelium at the top then the rest is stratified columnar.

internal urinary sphincter

junction of urinary bladder and urethra. elastic CT and smooth muscle prevents urine leakage

external urinary sphincter

skeletal muscle surrounds urethra as it extends through pelvic floor. voluntary.

male urethra

extends from inferior part of urinary bladder through to tip of penis

female urethra

shorter, opens into vestibule anterior to vaginal opening

function of renal system

excretion to rid the body of waste products through urine.

regulation of blood volume and blood pressure.

regulation of solute concentration in blood, extracellular pH, RBC synthesis, vitamin D synthesis

production of urine

kidneys- regulate body fluid composition. sort chemicals in blood for removal or for return into blood

nephrons- structural component of kidneys that sorts the blood

urine production- 3 stages: filtration, tubular reabsorption, tubular secretion

filtration (process 1)

movement of fluid derived from blood flowing through glomerulus across filtration membrane

removes toxins quickly from blood