Biology 10 Chapter 37
Circulatory and
Respiratory Systems
37-1 The Circulatory System
Organisms composed of a small number
of cells do not need a circulatory system
- oxygen and nutrients can diffuse
across cell membranes
Larger organisms cannot rely on diffusion
- they need a circulatory system
37-1 The Circulatory System
The human circulatory system consists of
the heart, a series of blood vessels, and
the blood that flows through them.
The Heart
- composed almost entirely of muscle
- about the size of a fist
- enclosed in a protective sac of tissue
called a pericardium
37-1 The Circulatory System
- inside the walls of the heart is a thick
layer of muscle called the myocardium
- contractions pump blood through
the circulatory system
- the heart contracts about 72 times a
minute, pumping about 70 ml of blood
with each contraction
37-1 The Circulatory System
- the septum is a wall that divides the
right side of the heart from the left side
- prevents the mixing of oxygenpoor and oxygen-rich blood
- on each side of the septum are two
chambers
- the atrium is the upper chamber
and receives the blood
37-1 The Circulatory System
- the ventricle (the lower chamber)
pumps blood out of the heart
Heart animation
Circulation through the body
- pulmonary circulation: the right side
of the heart pumps blood from the heart to
the lungs
- systemic circulation: the left side of
the heart pumps blood to the body
37-1 The Circulatory System
37-1 The Circulatory System
Capillaries of
head and arms
Superior
vena cava
Pulmonary
vein
Capillaries of
right lung
Aorta
Pulmonary
artery
Capillaries
of left lung
Inferior
vena cava
Capillaries of
abdominal organs
and legs
37-1 The Circulatory System
Blood flow through the heart
- blood enters through an atria
- as the heart contracts, blood flows into
the ventricles, and then out
- valves: flaps of connective tissue
between the atria and ventricles that keep
blood flowing in one direction
Blood flow movie
37-1 The Circulatory System
Heartbeat
- each contraction begins in a small
group of muscle cells in the right atria
- cells are called the sinoatrial node
(SA node) or pacemaker
- when the atria contracts, blood flows
into the ventricles; when the ventricles
contract, blood exits the heart
37-1 The Circulatory System
Sinoatrial (SA)
node
Conducting fibers
37-1 The Circulatory System
Conducting fibers
Atrioventricular
(AV) node
37-1 The Circulatory System
Blood Vessels
- aorta: large vessel that blood leaves
the heart from to transport oxygen to
the body
As blood flows through the circulatory
system, it moves through three types of
blood vessels- arteries, capillaries, and
veins
37-1 The Circulatory System
- arteries: large vessels that carry
blood from the heart to the tissues of
the body
- capillaries: smallest blood vessels;
they have thin walls that allow for the
transport of nutrients, gasses, and
wastes
37-1 The Circulatory System
- veins: blood vessels that returns
deoxygenated blood to the heart;
contain one-way valves
Blood pressure
- measures the force of the blood on
the arteries
- two numbers (systolic and diastolic
pressures); 120/80
37-1 The Circulatory System
Vein
Artery
Endothelium
Arteriole
Capillary
Venule
Connective
tissue
Connective
tissue
Smooth
muscle
Endothelium
Smooth
muscle
Endothelium
Valve
37-1 The Circulatory System
37-1 The Circulatory System
37-1 The Circulatory System
Disorders of the circulatory system
atherosclerosis: when fatty deposits
called plaques build on the walls of
arteries
- obstruct the flow of blood
High blood pressure
- forces the heart to work harder; may
cause a heart attack or stroke
37-1 The Circulatory System
37-1 The Circulatory System
Heart attack
- if arteries become blocked, part of the
heart may die from a lack of oxygen
Stroke
- blood clots get stuck in the blood
vessels leading to parts of the brain;
also caused by an artery bursting in the
brain
Section Quiz
The layer of muscle in the heart that pumps
blood through the circulatory system is called
the




myocardium.
atrium.
ventricle.
vena cava.
Section Quiz
Oxygen-poor blood from the body enters the
heart through the




left atrium.
left ventricle.
right atrium.
right ventricle.
Section Quiz
Atherosclerosis is a condition in which




blood cells die from a lack of oxygen.
plaque builds up along the walls of the arteries.
blood pressure is too high.
the heart stops pumping blood.
Section Quiz
The vein that brings oxygen-poor blood from the
upper part of the body to the right atrium is the




pulmonary vein
inferior vena cava.
aorta
superior vena cava.
37-2 Blood and the
Lymphatic System
Blood
- connective tissue that contains both
dissolved substances and specialized
cells
- collects oxygen from the lungs,
nutrients from the digestive tract, and
waste products from tissues
37-2 Blood and the
Lymphatic System
The human body contains 4 to 6 liters of
blood
- 45% are cells
- 55% is blood plasma
Plasma is about 90% water and 10%
gases, salts, nutrients, and plasma
proteins
37-2 Blood and the
Lymphatic System
Plasma proteins are divided into three
groups: albumins, globulins, and
fibrinogen
- albumins and globulins transport
substances
- fibrinogen clots blood
37-2 Blood and the
Lymphatic System
Plasma
Platelets
White blood
cells
Red blood
cell
Whole Blood
Sample
Sample Placed
in Centrifuge
Blood Sample
That Has Been
Centrifuged
37-2 Blood and the
Lymphatic System
Blood cells
The cellular portion of blood consists of
red blood cells, white blood cells, and
platelets
Red Blood Cells (RBC)
- also called erythrocytes
- transport oxygen through the body
37-2 Blood and the
Lymphatic System
- hemoglobin is the iron-containing
protein that binds to oxygen; make cells
red
- RBC are produced in the red bone
marrow
- live around 4 months (120 days)
37-2 Blood and the
Lymphatic System
37-2 Blood and the
Lymphatic System
White blood cells (WBC)
- also called leukocytes
- attack foreign substances or
organisms
- can live for several months
- phagocytes engulf and digest foreign
cells
37-2 Blood and the
Lymphatic System
Platelets
Blood clotting is made possible by plasma
proteins and cell fragments called
platelets
- platelets contact blood vessels; their
surfaces become sticky; several group
around a wound
37-2 Blood and the
Lymphatic System
Break in Capillary Wall
Clumping of Platelets
Clot Forms
Blood vessels injured.
Platelets clump at the site
and release thromboplastin.
Thromboplastin converts
prothrombin into thrombin..
Thrombin converts
fibrinogen into fibrin, which
causes a clot. The clot
prevents further loss of
blood..
37-2 Blood and the
Lymphatic System
37-2 Blood and the
Lymphatic System
Lymphatic system
A network of vessels called the lymphatic
system collects the fluid that is lost by
the blood and returns it to the
circulatory system
Lymph: fluid that collects in capillaries
and flows to larger vessels
37-2 Blood and the
Lymphatic System
Section Quiz
The plasma protein that responsible for blood
clotting is




albumin.
fibrinogen.
globulin.
hemoglobin.
Section Quiz
White blood cells that engulf and digest foreign
cells are known as




phagocytes.
platelets.
antibodies.
thrombocytes.
Section Quiz
Blood cells that do not have nuclei and are
produced by the red bone marrow are




red blood cells.
lymphocytes.
platelets.
phagocytes.
Section Quiz
The function of platelets is to




assist red blood cells in carrying oxygen.
destroy viruses and bacteria.
initiate the blood clotting process.
keep capillaries open so blood can flow freely
through.
Section Quiz
The function of lymph nodes is to




trap bacteria and viruses that cause disease.
produce antibodies.
manufacture new red and white blood cells.
store fat.
37-3The Respiratory System
“Respiration” is used in biology in two
different ways.
- cellular respiration: the release of
energy from food w/ oxygen; makes
ATP
- respiration: the process of exchanging
oxygen and carbon dioxide
37-3The Respiratory System
The job of the respiratory system is to
exchange oxygen and carbon dioxide.
The respiratory system consists of the
nose, pharynx, larynx, trachea, bronchi,
and lungs
Respiration movie
37-3The Respiratory System
Nose
Pharynx
Larynx
Mouth
Trachea
Lungs
Bronchus
Epiglottis
Bronchioles
Diaphragm
37-3The Respiratory System
Pathway of air
- air moves through the nose to a tube
at the back of the mouth called the
pharynx, or throat
- serves as a passageway for air and
food
- air moves from the pharynx to the
trachea, or windpipe
37-3The Respiratory System
- air passes larynx which contains
the vocal chords
- air passes through the trachea into
two passageways called bronchi
- each bronchus leads to a lung
- the bronchi branch into bronchioles
37-3The Respiratory System
- the bronchioles subdivide until they
reach millions of tiny air sacs called
alveoli
- alveoli are clustered into groups
that resemble bunches of grapes
- the alveoli are the location of gas
exchange
37-3The Respiratory System
Alveoli
Bronchiole
37-3The Respiratory System
37-3The Respiratory System
37-3The Respiratory System
Gas Exchange
- oxygen dissolves on the surface of the
alveoli and then diffuses across
capillaries into the blood
- carbon dioxide diffuses in the opposite
direction
37-3The Respiratory System
O2
Capillary
37-3The Respiratory System
O2
CO2
Capillary
37-3The Respiratory System
Breathing
- the lungs are located inside the chest
cavity. At the bottom of the cavity is the
diaphragm
- when you inhale, the diaphragm contracts
- when you exhale, the diaphragm relaxes
Breathing animation
37-3The Respiratory System
Air
exhaled
Air
inhaled
Rib cage
descends
Rib cage
rises
Diaphragm
Diaphragm
Inhalation
Exhalation
Section Quiz
Air passes through the trachea into two large
passageways in the chest cavity known as the




bronchi.
alveoli.
epiglottis.
bronchioles.
Section Quiz
The function of the cilia lining the respiratory
surfaces is to
 improve the amount of oxygen and carbon
dioxide exchanged in the lungs.
 cover the opening of the trachea when you
swallow.
 move air in and out of the lungs.
 sweep trapped particles and mucus away
from the lungs.
Section Quiz
Oxygen diffuses from the alveolus into the blood
because




blood entering the capillaries of the lungs is oxygenpoor.
blood entering the capillaries of the lungs is oxygenrich.
air entering the lungs has more carbon dioxide than
oxygen.
air entering the lungs has less oxygen than is found
in the blood.