The Cardiovascular System

1
The Cardiovascular System

• Circulating fluid (blood)
• The Heart
• Blood vessels

2
Physical Characteristics of Blood

• Sticky, opaque fluid
• Color varies from scarlet (O2 rich) to dark red
  (O2 poor)
• More dense than water, slightly alkalinic
  (7.35-7.45)
• Temperature(38C or 100F)
• 8 of body weight, 5-6L(volume)

3
FunctionsDistribution

• Deliver oxygen from lungs nutrients from GI
  tract to cells
• Transport metabolic wastes from cells to
  elimination sites (lungs, kidneys)
• Transport hormones

4
FunctionsRegulation

• Maintenance of body temperature
• Maintenance of pHproteins act as buffers
• Maintenance of adequate fluid volume in
  circulatory system

5
FunctionsProtection

• Prevention of blood loss
• Prevention of infection

6
Blood CompositionBlood Plasma

• 90 water 55 of whole blood volume
• 100 dissolved solutes (nutrients, gases,
  hormones, wastes, cell activity products
• Plasma proteins (1)Albumin accounts for 60 of
  plasmic proteins (2) immunoglobulins, transport
  proteins (35) (3) fibrinogen (4) clotting
  reaction

7
Blood CompositionFormed Elements

• Erythrocytes, leukocytes, platelets
• Two of the three are not true cells
• Most of the formed elements short life spans
• Amitotic (renewed by bone marrow)

8
Formed ElementsErythrocytes

• Biconcave shaped (maintained by spectrin) ideal
  for gas transport
• Anucleate, no organelles
• 97 Hb
• Hemocytoblastgtproerythroblastgtearly
  erythroblastgtlate erythroblast gtnormoblastgt
  reticulocytegterythrocyte
• Blood typingA, B, AB, O

9
Formed ElementsLeukocytes

• Provide immunity
• Less than 1 of total blood volume
• Diapedesis
• Amoebid motion
• Positive chemotaxis
• Leukopenia,leukocytosis
• Granulocytes, agranulocytes

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Granulocytes

• Neutrophils-Most numerous(70)granules contain
  peroxidases and hydrolytic enzymes
  polymorphonuclear 1st line of immune
  attackdefensins
• Eosinophils-(1-4) bilobed red nucleuslack
  bacteriolytic enzymesparasitic infections
  inactivate allergic reactions
• Basophils-(0.5)U or S shaped nucleus release
  histamine/contain heparin

11
Agranulocytes

• Monocytes-(4-8) largest WBC kidney shaped
  nucleimetamorphose into macrophages
• Lymphocytes-(20-30) 2nd most numerous
  leukocytescant cytoplasmlymphatic system
  componentspecific immunity
• T cells-attack foreign cells directly B
  cells-change into plasma cells that secrete
  antibodiesNK cells-immune surveillance

12
Platelets

• Cytoplasmic fragments of megakaryocytes
• Anucleate
• Regulated by thrombopoietin
• Hemostasis

13
The Cardiovascular SystemThe HeartOverview

• Heart chambersAtria,ventricles
• Pulmonary circuit
• Systemic, coronary circuit
• Arteries, veins, capillaries

14
The Heart Size, Location, and Orientation

• Weighs between 250-350 grams
• Located in mediastinum(extends obliquely from 2nd
  rib to 5th intercostal space)
• Base, apex

15
Coverings of the Heart

• Fibrous pericardium-(1) protection(2) anchors to
  surroundings (diaphragm,great vessels) (3)
  prevents blood overfill.
• Serous pericardium-(1) parietal layer lines inner
  fibrous pericardium(2)visceral layer
  (epicardium)(3) Pericardial cavity-in between

16
Layers of the Heart Wall

• Epicardium-often infiltrated with adipose
• Myocardium-layered cardiac muscle
  tissue(contractile), CT, blood vessels, nerves
• Endocardium-glistening white endothelial layer
  resting on CTcontinuous with endothelium

17
Cardiac Muscle Tissue

• Cardiocytes-central nucleus,myofibrils,
  intercalated discs,aerobic respirationhigh
  myoglobin glycogen/lipid reserves
• Circulatory supply more extensive vs.red muscle
  tissue
• Cardiocyte membranes bound together by
  intercalated discs (desmosomal cell junctions)
  functional syncytium.

18
Fibrous Heart Skeleton

• Collagen elastic fibers
• Encircle bases of pulmonary trunk/aorta and heart
  valves
• Functions(1) stabilizes cardiocyte/valve
  positionings (2) reinforcement of blood vessels
  nerves(3) elasticity

19
Anatomical Orientation and Superficial Heart
Anatomy

• Borders Superior, Right, Inferior, Left
• Sternocostal surface-rt.atrium ventricle
• Diaphragmatic surface-post./inf.wall of left
  ventricle
• Auricles
• Coronary sulci
• Interventricular sulci(ant.,post.)

20
Internal Anatomy/Organization of the Heart

• Right atria-superior/inferior vena cavae,coronary
  sinuspectinate muscles,
• interatrial septum, fossa ovalis
• Tricuspid valve
• Right ventricle-chordae tendineae, papillary
  muscles,trabeculae carneae, pulmonary semilunar
  valve, pulmonary trunk

21
Internal Anatomy/Organization of the Heart(contd)

• Left Atrium-Lt./Rt. Pulmonary veins
• Bicuspid valve
• Left ventricle-Aortic semilunar valve,aortic
  sinuses, ascending aorta
• Vestigial structuresLigamentum
  arteriosum(pulm.trunk, aortic arch),fossa ovalis

22
Coronary CirculationArterial Supply

• Left coronary arteryanterior interventricular
  art.(supplies intervent. septum ant.walls of
  rt./lt. ventr.) and circumflex art.(lt. atrium
  post.walls of lt. vent.)
• Right coronary artery marginal art. (supplies
  myocardium of lateral part (rt.side) and
  post.intervent.art.(post.ventr.walls)
• Anastomoses-fusing collateral routes

23
Coronary CirculationVenous Supply

• Coronary sinus-receives blood from great, middle,
  and small cardiac veins

24
Cardiac Cycle

• Systole-chamber contraction (atrial 0.1s,
  ventricular 0.3s)
• Diastole-chamber relaxation(0.4 s)
• (1)Period of ventricular filling(mid-to-late
  diastole) (2) Ventricular systole (isovolumetric
  contraction, ventricular ejection
  phases)(3)Isovolumetric relaxation (early
  diastole)

25
Cardiac CycleHeart Sounds

• 1st (lubb) sound- beginning ventricular systole
  
• 2nd (dupp)sound-beginning ventricular diastole
• 3rd/4th sounds associated with ventricular blood
  flow atrial contractions

26
Cardiac CycleCoordination of Cardiac Contractions

• Nodal cells-establish contraction rates(SA, AV
  nodes)
• Conducting fibers-distribute contractile stimuli
  to myocardium(AV bundle, Purkinge fibers)
• Bradycardia, Tachycardia

27
The Cardiovascular SystemBlood Vessels

• Blood vessels-closed delivery system that begins
  and ends at the heart
• Heartgtarteriesgtarteriolesgtcapillary bedgt
  venulesgtveinsgtheart

28
Structure of Blood Vessel Walls

• All blood vessels (except capillaries), are
  composed of three tunics surrounding a central
  blood-containing lumen.
• Tunica intima (interna)-endothelium (continuum of
  endocardium)
• Tunica media-Circular smooth muscle elastin
  regulated by vasomotor nerve fibers of ANS
  vasoconstriction/vasodilationthickest layer

29
Structure of Blood Vessel Walls (contd)

• Tunica externa (adventitia)-loose collagen fibers
  that protect/reinforce blood vesselinfiltrated
  with nerve fibers, lymphatic vessels, elastin
  fibers vasa vasorum.

30
Arterial System

• Elastic (conducting) arteries located near
  heart-aorta major branchesdiameters range from
  2.5cm to 1 cm contain elastin.
• Muscular(distributing) arteries-deliver to target
  organs and account for named arteries in human
  body middle tunic has more smooth muscleactive
  in vasoconstriction.

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Arterial System (contd)

• Arterioles-diameter ranges from 0.3mm to 10 µm
  larger arterioles/3 tunics
• Capillaries-smallest of blood vesselssingle
  tunic(intima)

32
Arterial System (contd)Types of Capillaries

• Continuous-abundant in skin and musclescomplete
  lining with tight junctions
• Fenestrated-have porous walls due to incomplete
  endothelium
• Sinusoids-highly modified leaky capillaries
  common in liver, bone marrow, lymphoid and
  endocrine organs
• Capillary Beds-microcirculation

33
Venous System

• Venules-range from 8 to 10 µm in diameterporous
• Veins-65 of total blood supply collect blood
  from all tissuesvein walls less elastic than
  arteriessparse tunica media, thick
  adventitiavalves

34
The Pulmonary Circuit

• Left/Right Pulmonary Arteries
• Pulmonary Arterioles
• Capillaries, alveoli
• Venules
• Pulmonary veins

35
The Systemic CircuitSystemic Arteries

• Ascending aorta
• Aortic arch
• Brachiocephalic trunk (rt. common carotid, rt.
  subclavian)
• Left common carotid
• Left subclavian

36
Subclavian Arteries and Branches

• Thyrocervical trunk-neck, shoulder upper back
• Internal thoracic-pericardium/ant.thoracic wall
• Vertebral artery-brain/spinal cord
• Axillary artery-pectoral region/axilla
• Brachial artery-upper limb
• Radial/ulnar arteries-antebrachium
• Superficial/deep palmar arch-palm
• Digital artery-thumb/fingers

37
The Carotid Arteries and Brain Blood Supply

• External carotid artery-neck, pharynx, esophagus,
  larynx, mandible, face
• Internal carotid artery-brain
• (IC branches)Ophthalmic artery-eyesanterior
  cerebral artery-frontal/parietalmiddle
  cerebral-midbrain, lat.cerebrum
• Vertebralgtbasilargtposterior cerebralgtposterior
  communicating arteriesgtmiddle cerebralgt anterior
  communicatinggtanterior cerebral

38
The Descending AortaThoracic Aorta Branches

• Visceral branches-Bronchial, pericardial,
  mediastinal,esophageal arteries.
• Parietal branches-Intercostal,superior phrenic.

39
The Descending AortaAbdominal Aorta Branches

• Unpaired arteries
• Celiac trunk-liver, stomach, spleen
  Branches-left gastric,splenic, common hepatic
  arteries.
• Superior mesenteric-pancreas, small intestine,
  most of large intestine.
• Inferior mesenteric-terminal colon rectum

40
Abdominal Aorta Branches (contd)

• Paired arteries
• Inferior phrenic
• Suprarenal
• Renal
• Gonadal
• Lumbar

41
Arteries of the Pelvis Lower Limbs

• Right/Left Common Iliacs
• Internal Iliac-urinary bladder, int.,ext. walls
  of pelvis, genitalia
• External Iliac-lower limbs

42
Arteries of Thigh Leg

• Femoral
• Deep femoral
• Popliteal
• Post., Ant. tibial
• Peroneal

43
Arteries of the Foot

• Dorsalis pedis
• Medial, Lateral plantar

44
Systemic CircuitSystemic veins

• Cranial venous return-Superior cerebral veins,
  superior sagittal sinus, great cerebral
  vein,straight/sigmoid sinus,internal jugular.
• Vertebral veins empty into brachiocephalic veins.
• Temporal, facial, maxillary empty into the
  external jugular

45
Systemic Veins

• Brachium venous return-
• Digital veins
• Superficial/deep palmar
• Palmar venous arches
• Cephalic
• Median antebrachial
• Basilic
• Median cubital (cephalic, basilic)
• Axillary (basilic, brachial)

46
Systemic Veins

• SVC formation
• Subclavians
• Brachiocephalics(vertebrals,ext/int jugulars)
• Azygos(hemiazygos)-chief blood collectors of
  thorax

47
Systemic VeinsTributaries of the IVC

• Pelvic limb venous drainage
• Plantar/dorsal venous arch
• Anterior/ posterior tibial
• Peroneal
• Popliteal
• Femoral
• Great/small saphenous
• External iliac

48
Systemic VeinsVeins Draining the Pelvis

• Internal iliac-pelvic organs
• Common iliac
• Veins Draining the Abdomen
• Lumbar
• Gonadal
• Hepatic
• Renal
• Suprarenal
• Phrenic

49
Hepatic Portal System

• Tributaries
• Inferior mesenteric
• Splenic
• Superior Mesenteric
• Hepatic portal vein formed by fusion of
  superior mesenteric and splenic