unit ii: transport cardiovascular system ii
DESCRIPTION
Unit II: Transport Cardiovascular System II. Chapter 18: pp 657-671 Chapter 17: pp 595-619. Cardiac Output (CO). 40. Maximum for trained athletes exercising at peak levels. Amount ejected by ventricle in 1 minute Cardiac reserve : with fitness, with disease. 35. 30. Normal range - PowerPoint PPT PresentationTRANSCRIPT
Unit II: TransportCardiovascular System II
Chapter 18: pp 657-671
Chapter 17: pp 595-619
• Amount ejected by ventricle in 1 minute
• Cardiac reserve: with fitness, with disease
Maximum for trained athletesexercising at peak levels
Normal rangeof cardiacoutput duringheavy exercise
Average resting cardiac output
Some forms ofheart failure
Cardiacoutput
(L/min)
0
5
10
15
20
25
30
35
40
HR: 75 beats/min SV: 80 mL/beat CO: 6000 mL/min=x
Cardiac Output (CO)
Cardiac Output (CO)
Body temperature
ANSHormones
Muscular contractions
Blood volume
Peripheral blood flow
Venous return ↑ = ↑ SV
EDV
Influences the efficiency of contractions
ESV
↑ Filling time = ↑ ESV
↑ afterload = ↓ pumping efficiencyand ↑ESV
Vasodilation
Vasoconstriction
↑ contractility = ↓ ESV
ANS Hormones
STROKE VOLUME (SV) = EDV – ESVHEART RATE (HR)
CARDIAC OUTPUT (CO) = HR x SV
Factors affecting heart rate (HR) Factors affecting stroke volume (SV)
Heart Rate
• Pulse:
– infants have HR of 120 bpm or more
– young adult females avg. 72 - 80 bpm
– young adult males avg. 64 to 72 bpm
– HR rises again in the elderly
• Tachycardia:
– stress, anxiety, drugs, heart disease or body temp.
• Bradycardia:
– in sleep and endurance trained athletes
Bradycardia Tachycardia
Normal range ofresting heart
rates
60 bpm 100 bpm
• Tunica interna: repels blood cells and platelets
– simple squamous endothelium overlying a basement membrane
• Tunica media: smooth muscle, collagen, elastic tissue
• Tunica externa: loose connective tissue
Tunica externa
Tunica media
Tunica intima
Endothelium
Smooth muscle
Vein
The structureof the wall ofa vein
LM x 60
Vein
Artery
Anatomy of Blood Vessels
Arteries
3 Categories by Size:• Conducting (elastic) arteries
– pulmonary, aorta & common carotid
• Distributing (muscular) arteries– Brachial, femoral and splenic
• Resistance (small) arteries
– Arterioles
Capillaries
Arterioles
Distributing/Muscular Arteries
Conducting/Elastic Arteries
Internal elastic layerTunica intimaTunica mediaTunica externa
Tunica intimaTunica mediaTunica externa
Smooth muscle cellsEndothelium
Endothelial cells
Basal lamina
Veins
• thinner tunica media
• 3 Categories by Size:
– Small veins
• venules
– Medium veins
• Radial, ulnar veins
• valves prevent backflow
– Large veins
– Vena cava, pulmonary, jugular
Large Veins
Medium-sized Veins
Venules
Capillaries
Basal lamina
Endothelial cells
Pores
EndotheliumTunica externa
Tunica externaTunica mediaTunica intima
Tunica externaTunica mediaTunica intima
Filtration Predominates
No Net Movement
Reabsorption Predominates
24 L/day 20.4 L/day
ArterioleVenule KEY
CHP (Capillaryhydrostatic pressure)BCOP (Blood colloidosmotic pressure)NFP (Net filtrationpressure)
35 25 25 25 2518mm mmmmmmmmmmHg HgHgHgHgHg
NFP = +10 mm Hg NFP = 0
NFP = –7 mm Hg
Capillary
CHP > BCOP CHP = BCOP BCOP > CHP
Capillaries• Smallest blood vessels
• Only vessels that allow exchange of materials
• Anatomy:
– simple squamous endothelium with basement membrane
– walls: 0.2-0.4 µm thick; lumen: 5-9 µm diameter
Capillary Beds
•Metarterioles
– connect arterioles to capillaries
•Thoroughfare channel
– connect capillaries to venule
•Perfusion
– precapillary sphincter
Gap betweenadjacent cells
Basal laminaEndothelial cell
Nucleus
Types of Capillaries
• Continuous – (4nm)
– endothelial cells have tight junctions
• Fenestrated – (20-100nm)
– organs that require rapid absorption or filtration
– Ex. kidneys, small intestine
• Sinusoids – (30-40nm)
Basal laminaEndothelial cell
Nucleus
Circulatory Routes• Most common route
– heart arteries arterioles capillaries venules veins heart
• Portal system
• hypothalamus – pituitary
• in kidneys
• intestines – liver
• Anastomoses
• Arteriovenous anastomosis
• Ears, fingers, toes, palms
Blood Pressure
• Force that blood exerts against a vessel wall
• Measured at brachial artery of arm
• Systolic pressure and diastolic pressure
• Normal value, young adult: 120/75 mm Hg
Blood Pressure
• Importance of arterial elasticity
– expansion and recoil maintains steady flow of blood throughout cardiac cycle, smoothes out pressure fluctuations and stress on small arteries
• BP rises with age: arteries less distensible
Leastresistance,greatest flowat center
Greatest resistance,slowest flow near surfaces
Internal surface area = 2
Internal surface area = 1
Resistance to flow = 1Flow = 1
Resistance to flow = 2Flow = ½
Blood Pressure
BP determined by:
• cardiac output
• blood volume
• peripheral resistance
– Blood viscosity
– Vessel length
– Vessel radius (vasomotion)
R. Common carotidR. Subclavian
Brachiocephalictrunk
AxillaryAscending aorta
Brachial
Radial
Ulnar
Femoral
Aortic archDescending aortaDiaphragm
Renal
Common iliac
Arteries
Veins
External jugularInternal jugularSubclavian
Brachiocephalic
AxillaryBrachial
Radial
Ulnar
Femoral
Superior vena cava
Diaphragm
Inferior vena cavaRenal
Common iliac
Fetal Development and Circulation
• Fetus = from 8 weeks until birth
• Fetal circulation– umbilical-placental circuit– circulatory shunts
• ductus venosus• foramen ovale• ductus arteriosus
Foramen ovale
Ductus arteriosus
Pulmonarytrunk
Inferior vena cava
Ductus venosus
Umbilical arteries
Umbilical vein
Umbilicalcord
Placenta
Aorta
Liver
Blood Circulation Before Birth