Transcript The Heart and Circulation

The Heart and Circulation
Cardiovascular System = Heart, Blood and Vessels
Lymphatic System = Lymph nodes, Organs and Vessels
The Heart
• External Innervation
– Vagus (parasympathetic)
– C + T sympathetic chain ganglion
• 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
pg 502
Location of Heart in Chest
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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
Location of Heart in Thorax
pg 501
External Features of Heart
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pg 504
Interventricular sulcus
Coronal/Coronary sulcus
Auricles of atria
Apex
Base
Coronary vessels
Ligamentum Arteriosum
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 504, 532
• Epicardium (most superficial)
– Visceral pleura
• Myocardium (middle layer)
– Cardiac muscle
– Contracts
Layers of
Heart
• Endocardium (inner)
– Endothelium on CT
– Lines the heart
– Creates the valves
pg 502
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 = rough Pectinate muscle
– Fossa Ovalis- on interatrial septum, remnant of Foramen Ovale
• Right Ventricle
– Receives O2-poor blood from right atrium through tricuspid valve
– Pumps blood to lungs via Pulmonary Semilunar Valve in
pulmonary trunk
– Trabeculae Carnae muscle ridges along ventral surface
– Papillary Muscle-cone-shaped muscle to which chordae tendinae
are anchored
– Moderator Band-muscular band connecting anterior papillary
muscle to interventricular septum
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
– Pumps blood into aorta via Aortic Semilunar Valve to
body
– Same structures as Rt Ventricle: Trabeculae carnae,
Papillary muscles, Chordae tendinae
– No Moderator Band
Chambers of Heart
Heart Valves: Lub*-Dub**
• *Tricuspid Valve: Right AV valve
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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
• **Semilunar valves: prevents backflow in large arteries
– Pulmonary Semilunar Valve: Right Ventricle and Pulmonary Trunk
– Aortic Semilunar Valve: Left Ventricle and Aorta
– 3 cusps: blood rushes past they’re flattened, as it settles they’re pushed down
(valve closed)
Heart Valves
pg 506
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
Cardiovascular Circuits
pg 500
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
Blood Flow to Supply the Heart Muscle
• Heart wall too thick for diffusion
of nutrients
• Rt and Lft Coronary Arteries
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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
Anatomy of Arteries and Veins
• Tunica externa
– Outermost layer
– CT w/elastin and collagen
– Protects, Strengthens,
Anchors
• Tunica media
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Middle layer
Circular Smooth Muscle
Collagen & Elastic Fibers
Vaso-constriction/dilation
• Tunica intima
– Innermost layer
– Endothelium
– Minimize friction
• Lumen
pg 525
Vessels of Cardiovascular System:
Arteries
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Carry blood AWAY from heart
Systemic Circuit: carry O2 blood
Pulmonary Circuit: carry de-O2 blood
Walls thicker than Veins
– Tunica media > Tunica externa
• 3 Types
– Conducting (elastic)
• large, elastin, high pressure
– Distributing (muscular)
• medium size, to organs
– Arterioles
• smallest
Vessels of Cardiovascular System:
Capillaries
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Smallest blood vessels
Single layer of endothelium surrounded by basal lamina
Deliver O2 and nutrients to cells and remove waste
Capillary Beds: networks of caps. Regulating amount of
blood going to cells throughout tissues
• Tendons, Ligaments poorly vascularized
• Epithelium, cartilage has no capillaries
Vessels of Cardiovascular System:
Veins
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Carry blood from capillaries INTO the heart
Systemic Circuit: O2 poor blood
Pulmonary Circuit: O2 –rich blood
Thinner walls than arteries
– Tunica externa > tunica media, Less elastin
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Larger lumen than arteries
Contain valves (made of T. intima)
Normal movement, Muscular contraction push blood through
Venules- smallest veins
Movement through Veins
Pg 529
Cardiovascular Blood Flow
• HeartArteries(conducting-distributing)
ArteriolesCapillaries of tissues
• At Capillaries O2 is delivered and CO2 picked up
• CapillariesVenulesVeinsHeart
• Portal System: Special vascular circulation where blood
goes through 2 capillary beds before returning to the heart
to achieve 2nd function
– (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 548
Hepatic Portal System
Vascular Anastomoses
• Vessels unite and connect
• Arteriole Anastomoses
– Communication between arteries
– Joints, Abdominal Organs, Brain,
Heart
• Venous Anastomoses
– Communication between veins
– More common
– (eg) back of hand
• Vaso Vasorum
– Tiny arteries, veins, capillaries in
tunica externa of vessels to
nourish them (outer half)
Fetal Circulation: 2 main differences
• All major vessels are in place by 3rd month
• Blood flows in same direction as in adults
1) Fetus must transport blood
to and from the placenta
2) Lungs are not functional,
and do not need much
blood
Fetal Circulation: Blood to Placenta
• Fetus must supply placenta w/blood
• Umbilical Vessels: carries blood to/from placenta
– 2 Umbilical Arteries = bring blood that contains waste &
little O2 from fetus to placenta
– 1 Umbilical Vein = brings blood w/O2 and nutrients to
fetus from placenta (some goes to portal vein to process
in liver)
• Ductus Venosus = shunt taking blood returning from
placenta to fetus directly to heart, largely bypassing
liver
– Too much blood for liver to handle
– Results in highly O2 blood going to heart
Fetal Circulation: Bypassing the Lungs
• Fetal Lungs are not functional and do not need large
amounts of blood
• Foramen Ovale (becomes Fossa Ovalis)
– Small hole in inter-atrial septum allows blood to flow
directly from Rt. Atrium to Lft. Atrium
– This largely bypasses the Rt. VentriclePulmonary trunk
that would bring blood to lungs
• Ductus Arteriosus (becomes Ligamentum Arteriosum)
– Shunt directs blood from Pulmonary Trunk to Aortic
arch, largely bypassing lungs
Bypassing the Lungs
Pg 555
Remnants of Fetal Circulation
• Ligamentum teres = Round ligament
– Remnant of the umbilical vein
– Anterior abdominal wall
• Ligamentum venosum
– Remnant of ductus venosum
– On liver’s inferior surface
• Medial Umbilical Ligaments
– Remnant of umbilical arteries
– Anterior abdominal wall below navel
– Also gives branch to urinary bladder
The Lymphatic System
• Function: to collect excess tissue fluid collecting at
arteriole 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
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Pulse of nearby arteries
Contraction of surrounding skeletal muscle
Regular movement of body (wiggling legs)
Muscle in Tunica Media
• Lacteals-lymphatic capillaries w/unique function
– In mucosa of small intestine, receive digested fat from intestine
– Fatty lymph becomes milky = Chyle
– Chyle goes to bloodstream
Lymphatic System…The Players:
• Lymph- clear fluid from loose CT at capillaries
• 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)
– Lumbar, intestinal, bronchomediastinal, subclavian,
jugular
• Lymphatic ducts  empty into veins of neck