Biology 1112

1
Lecture 11

• Biology 1112
• Chapter 23 Circulation

2
Importance of Circulation

• Transports materials to all body cells
• Carries wastes away
• Very necessary if body is more than few cells
  thick

3
2 Basic Types

• Circulatory systems can be
• Open
• Closed

4
Open Circulation

• Blood vessels end in openings
• Organs bathed in blood
• Diffusion of wastes/materials happens by direct
  contact with blood
• Example insects, lobsters have open circulation

5
Closed Circulation

• Blood is confined to vessels
• 3 basic kinds of vessels
• Arteries
• Veins
• Capillaries
• Diffusion of materials/wastes through capillary
  membranes
• Requires an additional liquid outside vessels
  interstitial fluid

6
Blood Vessels Form Follows Function

• Arteries
• Veins
• Capillaries

7
Arteries

• Move blood away from heart
• Must withstand higher pressures
• Consist of epithelium, smooth muscle, connective
  tissue

8
Veins

• Move blood towards heart
• Have series of one-way valves
• In the legs, walking helps blood return to heart
• Consist of epithelium, valves, smooth muscle,
  connective tissue

9
Capillaries

• Must accommodate diffusion
• Very small, thin-walled, numerous
• Consist of only epithelium, basement membrane

10
Closed Circulation in Vertebrate Animals

• Two basic types
• Single circuit system
• Dual circuit system

11
Single Circuit System

• Example fish
• Fish heart has 2 chambers
• Atrium (passively receives blood)
• Ventricle (actively pumps blood)
• Circuit repeated is heart to gills to body

12
Disadvantage to Single Circuit

• Body gets only low pressure blood
• Why? Must pass through capillary bed in gills
• Small capillaries restrict pressure!

13
Dual Circuit Circulation

• Example mammals
• Heart has 4 chambers
• 2 atria
• 2 ventricles
• Circuits are
• Pulmonary circuit heart to lungs
• Systemic heart to body

14
Advantage to Dual Circuit

• Body cells can receive blood under high pressure
• Greater performance in burst activities

15
7th Inning Stretch
16
Human Circulatory System

• Identify, discuss function of each structure
• Dont rely on color picture!
• Exam will be b/w
• Red/blue doesnt identify arteries/veins!

17
Sample Questions

• Which veins carry oxygenated blood?

18
Sample Questions

• Which veins carry oxygenated blood?

19
Sample Questions

• Which arteries carry deoxygenated blood?

20
Sample Questions

• Which arteries carry deoxygenated blood?

21
Sample Questions

• Which side of the heart carries deoxygenated
  blood?

22
Sample Questions

• Which side of the heart carries deoxygenated
  blood?
• Dont be confused by this picture!

23
Sample Questions

• In passing from the atrium to ventricle, which
  valve must the blood go through?

24
Sample Questions

• In passing from the atrium to ventricle, which
  valve must the blood go through?

25
Sample Questions

• What is this structure?

26
Sample Questions

• The aorta

27
Cardiac Cycle

• 3 parts
• Diastole
• Systole
• Ventricle contraction

28
Diastole

• Heart is completely relaxed
• Blood flows into receiving chambers (atria)

29
Systole

• Atria contract
• Ventricles fill with blood

30
Ventricles Contract

• Blood propelled out of heart towards two places
• Lungs
• Body

31
Heart Beat Coordination

• S/A node
• S/A Sino-atrial
• The natural pacemaker
• Initiates heart beat
• Signals atria to contract
• Located in right atrium
• A/V node
• Receives signal from S/A node
• Delays signal approx. 0.1 sec
• In the wall between ventricles
• Tells ventricles to contract