Lecture AP Biology Chapter 42A Circulation

After studying this chapter you will be able to: Compare and contrast open and closed circulatory systems; compare and contrast the circulatory systems of fish, amphibians, reptiles, and mammals or birds; distinguish between pulmonary and systemic circuits and explain the function of each; trace the path of a red blood cell through the human heart, pulmonary circuit, and systemic circuit.

of the 4 macromolecules are chemically digested

excess calories?

a human heart

blood cell through the heart

Chapter 42 – Part I

Circulation

What you need to know:

route of mammalian circulation

Transport systems (circulation) linked

with gas exchange (respiration)

exchange

Ex larger animals

Circulatory System

Circulatory System = Blood + Vessels

+ Heart

Open circulatory system

Open circulatory system:

blood bathes organs directly

•Blood + lymph =

hemolymph

•Heart pumps hemolymph

into sinuses

•Ex arthropods, mollusks

Closed circulatory system

Closed circulatory system:

blood contained in vessels & pumped around body

•Blood and fluid separate

•Ex annelids, cephalopods, vertebrates

Figure 42.10a

Endothelium

Artery

Smooth muscle Connective tissue Capillary

Valve

Vein

Basal lamina Endothelium

Smooth muscle Connective tissue

Venule Arteriole

Types of Blood Vessels

arterioles venules

 Blood enters through an atrium and is

pumped out through a ventricle

 Fish = single circulation pathway single circulation pathway , 2

Double circulation pathways in

vertebrates

Pathway of blood through heart

Superior vena cava

Pulmonary artery

Capillaries

of right lung

Pulmonary vein

Aorta

Inferior vena cava

Right ventricle

Capillaries of abdominal organs and hind limbs

Right atrium

Aorta Left ventricle Left atrium Pulmonary vein

Pulmonary artery

Capillaries

of left lung

Capillaries of head and forelimbs

Figure 42.6

Cardiac cycle

 Diastole: relaxation or filling phase

resting)

by L ventricle during contraction (~70 ml)

Figure 42.8-3

Atrial and ventricular diastole

Atrial systole and ventricular diastole

Ventricular systole and atrial diastole

0.1 sec

0.4 sec

0.3 sec

2

1

3

Valves : prevent backflow of blood

 The atrioventricular (AV) valves atrioventricular (AV) valves

(tricuspid, bicuspid) separate each atrium and ventricle

 The semilunar valves semilunar valves control blood flow

to the aorta and the pulmonary artery

 “Lub-dup” sound = blood against closed AV valves (lub) / the semilunar (dup) valves

 Heart murmur: backflow of blood through

a defective valve

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Sinoatrial (SA) node: pacemaker of heart, in right atrium

 The pacemaker is regulated by two portions

of the nervous system: the sympathetic and parasympathetic divisions

pacemaker

the pacemaker

hormones (epinephrine) and temperature

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Blood Pressure

 BP = systolic/diastolic pressure

 Systolic: heart

contracts

 Diastolic: heart relaxed

 Normal: 120/70

 Pulse: rhythmic Pulse

bulging of artery walls with each heartbeat

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Blood pressure reading: 120/70

120

70

Sounds stop

Sounds audible in stethoscope

Direction of blood flow

in vein (toward heart) Valve (open)

and venules

Lymphatic System: returns lost fluid and proteins to blood as lymph

gases, nutrients, wastes, hormones

 Develop from stem cells in bone marrow

 Red blood cells (erythrocytes erythrocytes ): O2 transport

Osmotic balance,

pH buffering, and regulation

of membrane permeablity

Plasma proteins

Osmotic balance,

pH buffering Albumin

Fibrinogen

Immunoglobulins

(antibodies)

Clotting Defense

Substances transported by blood

Defense and immunity

Functions

Number per L (mm 3 ) of blood Cell type

Cellular elements 45%

Leukocytes (white blood cells) 5,000–10,000

Figure 42.18

Collagen fibers

Fibrin clot formation

Clotting factors from:

Platelets Damaged cells Plasma (factors include calcium, vitamin K) Enzymatic cascade



Cardiovascular Disease

deposits within arteries

blockage of one or more coronary arteries

the head

promotes atherosclerosis and increases the risk of heart attack and stroke

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Lumen of artery

Smooth muscle

Smooth muscle cell

T lymphocyte

cellular matrix

Extra-Foam cell Macrophage

Plaque rupture LDL

Cholesterol Fibrous cap

4 3

Figure 42.20