5 - circulation grays
TRANSCRIPT
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Circulation
Cardiovascular System = Heart, Blood and Vessels
Lymphatic System = Lymph nodes, Organs and Vessels
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The Lymphatic Vessels
Function:to collect excess tissue fluid collecting atarteriole end of capillary beds, and return leaked blood
proteins to blood (maintain osmotic pressure needed to
take up water into bloodstream) Lymph is moved through vessels
Pulse of nearby arteries
Contraction of surrounding skeletal muscle
Regular movement of body (wiggling legs) Muscle in Tunica Media
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Lymphatic SystemThe Players:
Lymph- clear fluid from loose CT at capillaries Contains small molecules of blood plasma, water, various
ions, nutrient molecules, respiratory gases
Lymphatic capillaries (near blood capillaries)
Lymph collecting vessels (small, 3 tunicas, #valves)
Lymph nodes (sit along collecting vessels)-clean
lymph of pathogens, they are NOT glands Lymphatic trunks(convergence large collecting
vessels)
Lymphatic ductsempty into veins of neck
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Lymphatic Ducts
Thoracic Duct Receives lymph from large trunks in abdomen and
thorax
Receives lymph from ducts of thoracic lymph nodes
Along vertebral bodies
Contain valves to ensure 1-way flow of lymph to lymph
nodes
Drains into left Brachiocephalic Vein (or subclavian or
int. jugular veins)
pg 154
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Functions of Heart and Cardiovascular
System
Cardiovascular System
Bulk flow of blood
Exchange with tissue
Heart Right side receives oxygen-poor blood from body
tissues and pumps the blood to the lungs
Left side receives the oxygenated blood from thelungs and pumps the blood throughout the body
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Location of Heart in Chest
Oblique Position
Apex = Left of Midline (5th ICS), Anterior to rest of heart
Base (posterior surface) sits on vertebral column
Superior Right = 3rd Costal Cartilage, 1 right midsternum
Superior Left = 2nd Costal Cartilage, 1 left midsternum
Inferior Right = 6th Costal Cartilage, 1 right midsternum
Inferior Left = 5th Intercostal Space at Midclavicular line
Pg 178
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Cardiac
Conduction
Intrinsic system initiating andcoordinating contraction of heartmuscle
Sinoatrial node (where SVC enters RA)
Atrioventricular node (in atrioventricularseptum)
AV Bundle (in IV septum then splits)
Purkinje fibers (throughout LV)
Cardiac Plexus (external innervation)
Vagus (parasympathetic)
Sympathetic trunkpg 201
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Blood Flow to Supply the Heart Muscle
Heart wall too thick for diffusion of nutrients Rt and Lft Coronary Arteries
Branch from Ascending Aorta
Have multiple branches along heart
Sit in Coronary Sulcus
Coronary Heart Disease
Cardiac Veins
Coronary Sinus (largest) Many branches feed into sinus
Sits in Coronary Sulcus
pg 193
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Pericardium
Pericardium (3 layers)
1) Outer-fibrous pericardium
Serous pericardium
2) parietal
3) visceral (epicardium)
Pericardial Cavity between layers of serous pericardium
serous fluid
lubricate heart while beating
pg177
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External Features of Heart
Interventricular sulcus
Coronal/Coronary sulcus
Auricles of atria
Apex
Base
Coronary vessels
Ligamentum Arteriosum
Pg 181
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The Great Vessels and major branches
Aorta (from Left Ventricle)
Ascending
Coronary arteries
Aortic Arch
Brachiocephalic trunk
Left Common Carotid
Left Subclavian
Descending (Thoracic/Abdominal)
Many small branches to organs
Pulmonary Trunk (from Rt Ventricle)- -2 Pulmonary Arteries into lungs
Inferior/Superior Vena Cava
- Coronary sinus
Pg 203
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Layers of Heart
Epicardium (most superficial)
Visceral serosa
Myocardium (middle layer) Cardiac muscle
Contracts
Endocardium (inner layer = lining)
Endothelium on CT
Lines the heart
Creates the valvesPg 190
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Fibrous Skeleton of Heart
Insertion for cardiac muscle
Anchors valve cusps
Prevents valves from opening too much Block electrical impulses from atria to
ventricles
Contains AV node
Pg 192
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Heart Chambers
2 receiving chambers: Right atria
Left atria
2 pumping chambers:
Right ventricle
Left ventricle
Atria are superior to ventricles Arrangement is not linearits twisted!
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Right Heart Chambers: Pulmonary Pump
Right Atrium (forms most of base of heart) Receives O2-poor blood from body via IVC, SVC, Coronary sinus
Ventral wall (w/Pectinate muscles) and dorsal wall (no pectinate muscles)
separated by crista terminalis
Fossa Ovalis- on interatrial septum, remnant of Foramen Ovale
Right Ventricle
Receives O2-poor blood from right atrium through tricuspid valve
Trabeculae Carnae- muscle ridgesalong ventral surface
Chordae Tendinae-fibrous cords running between AV valve cusps and papillary
muscles
Papillary Muscles (3)-cone-shaped muscles within ventricles to which chordae
tendinae are anchored
Moderator Band(septomarginal trabecula)-muscular band connecting anterior
papillary muscle to interventricular septum
Pumps blood to lungs via Pulmonary Semilunar Valvein pulmonary trunk
pg 186, 188
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Left Heart Chambers: Systemic Pump
Left Atrium Receives O2-rich blood from 4 Pulmonary Veins
Pectinate Muscles line only auricle
Left Ventricle (forms apex of heart) Receives blood from Left Atrium via bicuspid valve
Same structures as Rt Ventricle: Trabeculae carnae,
Papillary muscles (2), Chordae tendinae No Moderator band
Pumps blood into aorta via Aortic Semilunar Valveto
body
pg 189, 190
l b* b**
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Heart Valves: Lub*-Dub**
*Tricuspid Valve: Right AV valve
3 Cusps (flaps) made of endocardium and CT Cusps anchored in Rt. Ventricle by Chordae Tendinae
Chordae Tendinae prevent inversion of cusps into atrium
Flow of blood pushes cusps open
When ventricle is in diastole (relaxed), cusps hang limp in ventricle Ventricular contraction increases pressure and forces cusps
closed
*Bicuspid (Mitral) Valve: Left AV valve
2 cusps anchored in Left Ventricle by chordae tendinae Functions same as Rt. AV valve
They close together
pg 188
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Semilunar Valves (the dub)
Semilunar valves: prevents backflow in
large arteries
Pulmonary Semilunar Valve
Right Ventricle and Pulmonary Trunk
Aortic Semilunar Valve
Left Ventricle and Aorta
Made of 3 Cusps
As blood rushes past the cusps are flattened
As it settles theyre pushed down (valve closed)
pg 191
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Flow of Blood O2-poor blood (S+I VC, Coronary Sinus) enters Rt Atrium
Travels through Tricuspid Valve into Rt Ventricle Pumped out through Pulmonary Semilunar Valve into
Pulmonary trunk (branches into Pulmonary Arteries) and to
lungs
After circulating through lungs, O2-rich blood returns to the
heart through 4 Pulmonary veins
The O2-rich blood enters the Left Atrium
Travels through Bicuspid/Mitral Valve into Left Ventricle Pumped out through Aortic Semilunar Valve into Aorta to
be distributed to rest of body by descending aorta and
branches of aortic arch
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Cardiovascular Flow of Blood
HeartArteries(conducting-distributing)
ArteriolesCapillaries of tissues
At Capillaries O2
is delivered and CO2
picked
up
CapillariesVenulesVeinsHeart
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Circuits
Pulmonary Circuit
Vessels carrying blood to and from lungs
Pulmonary arteries and veins
Systemic Circuit
Vessels carrying blood to and from the rest of the
body
All other vessels
pg 185
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Blood Vessels
Powered by the heart!
Carry blood to and from the heart
3 main types:
Arteries
Carry blood away from heart
arterioles
Capillaries
Veins
Carry blood toward heart
Venules
Tunica externa
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Anatomy of
Arteries and
Veins
Tunica externa
Outermost layer
CT w/elastin and collagen
Vaso Vasorum
Tiny arteries, veins, capillaries on vessels to
nourish them (outer half)
Protects, Strengthens, Anchors
Tunica media
Middle layer
Circular Smooth Muscle
Collagen & Elastic Fibers
Vaso-constriction/dilation
Tunica intima
Innermost layer
Endothelium
Minimize friction
www.histology-world.com/keyfeatures/vessels1.htm
V l f C di l S t
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Vessels of Cardiovascular System:
Arteries
Carry blood AWAY from heart Systemic Circuit: carry O2blood
Pulmonary Circuit: carry de-O2blood
Walls thicker than Veins Tunica media > Tunica externa
3 Types
Conducting (elastic)
large, elastin, high pressure
Distributing (muscular)
medium size, to organs
Arterioles
smallest
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Capillaries
Smallest blood vessels
Lumen is typically only 1 RBC thick
Only 1 endothelial cell layer surrounded by basal lamina(no tunica media or externa)
Deliver O2and nutrients to cells and remove waste Capillary Beds: networks of capillaries
Regulating amount of blood going to cells throughout tissues
Supply tissues and organs that otherwise have poor capillarycirculation
Epithelium, cartilage has no capillaries
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Vessels of Cardiovascular System:
Veins
Carry blood from capillaries INTO the heart
Systemic Circuit: O2 poor blood
Pulmonary Circuit: O2rich blood
Pressure in Veins less than that in arteries
Thinner walls than arteries (tunica externa > tunica media, lesselastin)
Larger lumen than arteries Contain valves (made of T. intima)
Normal movement, Muscular contraction push blood through
Venules- smallest veins
C di l Bl d Fl
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Cardiovascular Blood Flow
Portal System: Special vascular circulation where
blood goes through 2 capillary beds beforereturning to the heart to achieve 2ndfunction
(eg) Hepatic Portal System: aids digestion by picking up
digestive nutrients from stomach + intestines and
delivers to liver for processing/storage
Pick-up occurs at capillaries of stomach and intestine
Via Hepatic Portal Vein goes to capillaries of liver
Via Hepatic Vein blood goes back to heart
pg 338
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Vascular Anastomoses
Vessels unite and connect
Arterial Anastomoses
Communication between arteries
Joints, Abdominal Organs, Brain, Heart
Venous Anastomoses
Communication between veins
More common
(eg) back of hand
pg 770
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Fetal Circulation
All major vessels in place by third month
2 main differences:
1. Fetus must supply blood to placenta
2. Lungs do not need much blood becauserespiratory organ is the placenta
www.medical-illustrator.co.uk
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1. Blood to Placenta
Umbilical vessels
Run in umbilical cord
2 umbilical arteries
Carry blood (little oxygen and waste) to placenta
1 umbilical vein
Returns this blood (with oxygen and nutrients) to fetus and to
portal vein (to liver)
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2. Bypassing the Lungs:
Foramen Ovale
Hole in the inter-atrial septum
Allows blood to flow from RA to LA Bypasses the RV
Would usually bring blood to lungs
Becomes the fossa ovalis postnatally
www.nmtmedical.com/heartrepair.aspx?id=78
pg 186
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2. Bypassing the Lungs:
Ductus Arteriosus
Carries blood from pulmonary trunk to aortic arch
Empties distal to coronary arteries
This enables the heart and brain to receive the most highlyoxygenated blood
Bypasses the lungs
Becomes the ligamentum arteriosum postnatally
www.wellesley.edu/.../Courses/111/mammalian.html
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First Breath!!
Lungs inflate
Ductus arteriosus constricts and closes
Oxygenated blood begins pouring into LA for
first time
Raises the pressure within the LA
This pushes the 2 flaps of foramen ovale together
and closes it