5 - Circulation Grays

8/13/2019 5 - Circulation Grays

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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
http://www.histology-world.com/keyfeatures/vessels1.htmhttp://www.histology-world.com/keyfeatures/vessels1.htmhttp://www.histology-world.com/keyfeatures/vessels1.htmhttp://www.histology-world.com/keyfeatures/vessels1.htm


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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
http://www.nmtmedical.com/heartrepair.aspx?id=78http://www.nmtmedical.com/heartrepair.aspx?id=78http://www.nmtmedical.com/heartrepair.aspx?id=78


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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
http://www.wellesley.edu/Biology/Courses/111/mammalian.htmlhttp://www.wellesley.edu/Biology/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

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