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Chapter 50: Circulatory Systems

• Evolution of Vertebrate Circulatory Systems• Mammalian Heart (The Pump)• Circulatory System (The Plumbing)• Regulation of the Circulatory System• Blood

The Oxygen Pathway: Circulatory SystemCirculatory system :

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Cardiovascular System consists of: 1.2.3.

Some Organisms do NOT need Circulatory Systems

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Purpose:

2 Types of Circulatory Systems

Larger Organisms NEED Circulatory Systems

Figure 50.1 Circulatory Systems (A and B)

Open circulatory system:

CONS:

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Figure 50.1 Circulatory Systems (C)

Closed circulatory system:

PROS:

Closed vascular system contains:• Arteries :

• Arterioles :

• Capillaries :

• Venules :

• Veins :

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Fish Heart (p 1048)

2 circulatory circuits evolved:Pulmonary circuit :

Systemic circuit :

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Lungfish Heart (p 1049)

Amphibian Heart (p 1049)

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Reptilian Heart (p 1050)

Crocodilian Heart (p 1050)

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Bird and Mammalian Heart (p 1050)

Figure 50.2 The Human Heart and Circulation (Part 2)

Low O2 blood from body into right atrium via large veins-Superior vena cava:-Inferior vena cava:

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Figure 50.2 The Human Heart and Circulation (Part 2)

1.

2.

3.

4.

Figure 50.2 The Human Heart and Circulation (Part 2)

1.

2.

3.

4.

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Pulmonary Pattern of Blood Flow

Heart Note the thickness changes

Venous Return

De-oxygenated Blood

Oxygenated Blood

Out To Lungs

Systemic Pattern of Blood Flow

Heart Note the thickness changes

Venous Return

De-oxygenated Blood

Oxygenated Blood

Out To Body

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Valves Prevent Back Flow

Valves enable:

Pulmonary & Aortic Valve (Semilunar Valves) :

Atrioventricular Valves :

Cardiac Cycle

Fig. 50.3

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ECG (Electrocardiogram)

Myocardium

Highly Specialized

Three areas of muscle:1.

2.

3.

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Cardiac muscle

Figure 50.7 The Action Potential of Ventricular Mu scle Fibers

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Specialized electrical conducting areas of the Heart (fig 50.6)1.

2.

3.

4.

Gap Junctions:

Carotid arteries & aorta have:

Cardiovascular control center has:

Fig. 49.18 CONTROL OF HEART RATE

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Nervous system adjusts HR:• Norepinephrine (sympathetic) increases:

• Acetylcholine (parasympathetic) increases:

Figure 50.11 Anatomy of Blood Vessels

Arteries/arterioles

Veins/venule

Neuronal & hormonal mechanisms:

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Figure 50.12 A Narrow Lane

Capillaries:

Why don’t capillaries get blown out by high pressureflow?

2.

1.

Fig. 50.16

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Figure 50.11 Anatomy of Blood Vessels (Part 2)

Blood pressure:

Resistance (R):1.

2.

*Blood pressure low in capillaries because of:

Figure 50.14 One-Way Flow

Blood Flow in Veins

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How Is Circulatory System Controlled and Regulated?

1. Autoregulatory mechanisms:

-Ex. Hyperemia : Low O2 & high CO2 levels

How Is Circulatory System Controlled and Regulated?

2. Endocrine & Nervous systems respond by changing:

Local changes affect central blood pressure & composition

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Cardiovascular control center in medulla also controls vessel constriction

• Epinephrine:

• Angiotensin:

Hormonal Influences

Sympathetic division acts on arteries/ arterioles:-norepinephrine:-acetylcholine (Ach):

Neurotransmitter Influences

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Blood Pressure (Flow)Blood Pressure (BP) = CO X R

Where CO is cardiac output and R is total resistanc e

Cardiac Output (CO )

Stroke Volume (SV)

CO = SV X HRWhere HR is heart rate

Frank–Starling law :

Ex: Exercise

How is Cardiac Output (CO) Adjusted?

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Circulatory HomeostasisBaroreceptors detect falling blood pressure1

2

3RESULT:

Increased baroreceptor activity signals rising blood pressure:1.

2.

3.RESULT:

Master of Circulatory Control

Dive Response:1.

2.

3.

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Blood PressureSystolic Pressure –

Diastolic Pressure –

Hypertension -

5 MAIN EFFECTS OF TRAINING

1.

2.

3.

4.

5.

The Effects Of Exercise On The Cardiovascular System