30.1 Respiratory and Circulatory Functions TEKS 4B, 10A, 10C KEY CONCEPT The respiratory and circulatory systems bring oxygen and nutrients to the cells

30.1 Respiratory and Circulatory Functions TEKS 4B, 10A, 10C

KEY CONCEPT The respiratory and circulatory systems bring oxygen and nutrients to the cells.


Oxygen-poor blood

Oxygen-rich blood

The respiratory and circulatory systems work together to maintain homeostasis.

• The circulatory system transports blood and other materials. – brings supplies to cells – carries away wastes – separates oxygen-poor and

oxygen-rich blood


• The respiratory system is where gas exchange occurs.– picks up oxygen from inhaled air – expels carbon dioxide and water

nose

sinus

mouth

epiglottistrachea

lungs


The respiratory system moves gases into and out of the blood.

• The lungs contain the bronchi, bronchioles, and alveoli. • Millions of alveoli give the lungs a huge surface area.• The alveoli absorb oxygen from the air you inhale.

alveolibronchiole


• Breathing involves the diaphragm and muscles of the rib cage.

• Air flows from areas of high pressure to low pressure.

Air inhaled.

Muscles contract andrib cage expands.

Diaphragm flattensand moves downward.

Air exhaled.

Muscles andrib cage relax.

Diaphragm relaxesand rises.


veins

arteries

The circulatory system moves blood to all parts of the body.

• The system includes the heart, arteries, veins, and capillaries. – heart pumps blood throughout body – arteries move blood away from

heart – veins move blood back to heart– capillaries get blood to and from

cells


– collecting waste materials– maintaining body temperature

• There are three major functions of the circulatory system.– transporting blood, gases, nutrients


Gas exchange occurs in the alveoli of the lungs.

• Oxygen and carbon dioxide are carried by the blood to and from the alveoli.– oxygen diffuses from alveoli into capillary – oxygen binds to hemoglobin in red blood cells – carbon dioxide difuses from capillary into alveoli

ALVEOLI GAS EXCHANGES

capillaries

alveolus

capillary

co2

o2

Co2 diffusesinto alveolus.

O2 diffusesinto blood.

30.2 Respiration and Gas Exchange


Gas exchange occurs in the alveoli of the lungs. • Breathing is regulated by the brain stem. It monitors CO2

levels, not O2

midbrainpons

medulla oblongata

spinal chord



Respiratory diseases interfere with gas exchange.

• Lung diseases reduce airflow and oxygen absorption.– Emphysema destroys alveoli.– Asthma constricts airways.– Cystic fibrosis produces sticky mucus.



• Smoking is the leading cause of lung diseases.



• The heart has four chambers: two atria, two ventricles.

• Valves in each chamber prevent backflow of blood.

• Muscles squeeze the chambers in a powerful pumping action.

aortic valve

left atrium

mitral valve

left ventricle

septum

pulmonary valve

right atrium

tricuspid

right ventricle

30.3 The Heart and Circulation


– SA node, or pacemaker, stimulates atria to contract– AV node stimulates ventricles to contract

SA node

VA node

• The heartbeat consists of two contractions.



• Blood flows through the heart in a specific pathway.

1

2 4

3



• Blood flows through the heart in a specific pathway.

– oxygen-poor blood enters right atrium, then right ventricle

– right ventricle pumps blood to lungs

– oxygen-rich blood from lungs enters left atrium, then left ventricle

– left ventricle pumps blood to body

aortic valve

left atrium

mitral valve

left ventricle

septum

pulmonary valve

right atrium

tricuspid

right ventricle



The heart pumps blood through two main pathways.

• A double-loop system

• Pulmonary circulation occurs between the heart and the lungs.– oxygen-poor blood enters lungs– excess carbon dioxide and water

expelled– blood picks up oxygen – oxygen-rich blood returns to heart



• Systemic circulation occurs between the heart and the rest of the body. – oxygen-rich blood goes to organs,

extremities– oxygen-poor blood returns to

heart • The two pathways help maintain a

stable body temperature.



Arteries, veins, and capillaries transport blood to all parts of the body.• Arteries carry blood away from the heart.

– blood under great pressure– Thicker, more muscular walls

ARTERY VEINCAPILLARIES

arteriole venule

endothelium

connective tissue

smooth musclevalve

30.4 Blood Vessels and Transport


• Veins carry blood back to the heart.

– blood under less pressure– thinner walls, larger diameter– valves prevent backflow



arteriole venule

endothelium

connective tissue

smooth musclevalve


• Capillaries move blood between veins, arteries, and cells.



arteriole venule

endothelium

connective tissue

smooth musclevalve


• Blood pressure is a measure of the force of blood pushing against artery walls. – systolic pressure:

left ventricle contracts

– diastolic pressure: left ventricle relaxes

• Shrinking diameter due to plaque increases blood pressure.• High blood pressure can precede a heart attack or stroke.



Lifestyle plays a key role in circulatory diseases. • Some choices lead to an increased risk of circulatory

diseases.– smoking– long-term stress– excessive weight– lack of exercise – diet low in fruits

and vegetables,high in saturatedfats



• Circulatory diseases affect mainly the heart and the arteries.– artery walls become thick and inflexible– plaque blocks blood flow in arteries



Blood is composed mainly of cells, cell fragments, and plasma.

• Whole blood is made up of different materials.– plasma– red blood cells – white blood cells – platelets

red blood cells,white blood cells,and platelets

plasma• Plasma is a key factor in maintaining

homeostasis. – molecules diffuse into and out of

plasma– contains proteins that stabilize

blood volume– contains clotting factors – contains immune proteins

30.5 Blood


Platelets and different types of blood cells have different functions.• The bone marrow manufactures most of the blood

components.

red blood cell

platelet

white blood cell

30.5 Blood


• Red blood cells make up 40-45 % of all blood cells.– transport oxygen to cells and carry away carbon dioxide– have no nuclei and contain hemoglobin

30.5 Blood


• White blood cells fight pathogens and destroy foreign matter.

red blood cell

platelet

white blood cell

30.5 Blood


• Protein markers define blood types and Rh factors.

– ABO blood group the most common

– Rh factor can be negative or positive– blood types must be compatible for transfusions

30.5 Blood


• Platelets help form clots that control bleeding.

platelets

fibrin

red blood cell

white blood cell

30.5 Blood


Lymph is collected from tissues and returned to the circulatory system.

• The lymphatic system collects fluid that leaks out of the capillaries.– Lymph vessels have valves to

prevent backflow.– Lymph nodes filter the lymph

and destroy foreign matter.– Lymph vessels return cleaned

fluid to the circulatory system. • If lymph vessels or nodes are

damaged, lymph collects in an area.

heart

lymph nodes

lymph vessels

30.6 Lymphatic System


tonsils

thymus

spleen

The lymphatic system is a major part of the immune system.

• Structures in the lymphatic system help fight disease.– tonsils filter bacteria

and viruses– thymus develops white

blood cells – spleen filters lymph,

contains immune cells

• Lymphocytes help destroy pathogens, parasites, and foreign matter.

30.6 Lymphatic System

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30.1 Respiratory and Circulatory Functions TEKS 4B, 10A, 10C KEY CONCEPT The respiratory and circulatory systems bring oxygen and nutrients to the cells