Bio Chapter 42 - Circulation and the Respiratory System

What tissue is involved in exchange?

Simple epithelium

Circulatory systems...

link exchange surfaces with cells throughout the body.

Small molecules can move between cells and their surroundings by ______

diffusion

In most animals, cells exchange materials with the environment via a ______.

fluid-filled circulatory system

A circulatory system has...

A circulatory fluid
A set of interconnecting vessels
A muscular pump, the heart

Circulatory systems can be open or closed (True or false)

True

The circulatory system connects the fluid that surrounds cells with the organs that exchange _________, absorb _________, and _________

gases (respiratory), nutrients (digestive), dispose of wastes (excretory)

cardiovascular system

The closed circulatory system that humans and other vertebrates have.

The three main types of blood vessels

arteries, veins, and capillaries
(Blood flow is one way in these vessels)

Arteries branch into ______ and carry blood away from the heart to _______.

arterioles, capillaries

capillary beds

Networks of capillaries, the sites of chemical exchange between the blood and interstitial fluid

Venules

converge into veins and return blood from capillaries to the heart

Arteries and veins are distinguished by the direction of blood flow, not by O2 content (True or false)

True :)

Vertebrate hearts contain ______ chambers

two or more

Blood enters through an _____ and is pumped out through ______

atria, ventricles

Amphibians, reptiles, and mammals have ________

double circulation

__________________ blood are pumped separately from the right and left sides of the heart

Oxygen-poor and oxygen-rich

The human heart is about the size of __________

a clenched fist and consists mainly of cardiac muscle

The two atria have relatively ______ and serve as ________ for blood returning to the heart

thin walls, collection chambers
(The ventricles have thicker walls and contract much more forcefully)

cardiac cycle

The heart contracts and relaxes in a rhythmic cycle

systole

The contraction, or pumping, phase of the heart

diastole

The relaxation, or filling, phase of the heart

cardiac output

The volume of blood pumped into the systemic circulation per minute and depends on both the heart rate and stroke volume

heart rate

the number of beats per minute

stroke volume

is the amount of blood pumped in a single contraction

What four valves prevent backflow of blood in the heart?

Two atrioventricular (AV) valves separate each atrium and ventricle
Two semilunar valves control blood flow to the aorta and the pulmonary artery

Some cardiac muscle cells are auto rhythmic, meaning....

they contract without any signal from the nervous system

sinoatrial (SA) node

pacemaker, sets the rate and timing at which cardiac muscle cells contract

Impulses that travel during the cardiac cycle can be recorded as an...

electrocardiogram (ECG or EKG)

The pacemaker is regulated by two portions of the nervous system:

the sympathetic and parasympathetic divisions
- The sympathetic division speeds up the pacemaker
- The parasympathetic division slows down the pacemaker
- The pacemaker is also regulated by hormones and temperature

Why is velocity of blood flow the slowest in the capillary beds?

As a result of the high resistance and large total cross-sectional area
Blood flow in capillaries is necessarily slow for the exchange of materials

Blood flows from areas of ______ pressure to areas of _____ pressure

higher, lower

Blood pressure is a force exerted in all directions, including against the walls of blood vessels (True or false)

True

The recoil of elastic arterial walls (elastic fibers) plays a role in...

maintaining blood pressure

Blood pressure is generally measured for an artery in the arm at the same height as the heart
Blood pressure for a healthy 20-year-old human at rest is about 120 mm Hg at systole and 70 mm Hg at diastole

Systolic pressure

the pressure in the arteries during ventricular systole; it is the highest pressure in the arteries

pulse

the rhythmic bulging of artery walls with each heartbeat

Diastolic pressure

the pressure in the arteries during diastole; it is lower than systolic pressure

Homeostatic mechanisms

regulate arterial blood pressure by altering the diameter of arterioles

Vasoconstriction

the contraction of smooth muscle in arteriole walls; it increases blood pressure

Vasodilation

the relaxation of smooth muscles in the arterioles; it causes blood pressure to fall

Fainting is caused by...

inadequate blood flow to the head Because blood pressure is low in veins, one-way valves in veins prevent the backflow of blood, Return of blood is also enhanced by contraction of smooth muscle in venule walls and skeletal muscle contraction.

Blood flows through only _____ of the body's capillaries at any given time

5-10%

- Capillaries in major organs are usually filled to capacity
- Blood supply varies in many other sites

lymphatic system

returns fluid that leaks out from the capillary beds

lymph

Fluid lost by capillaries
- The lymphatic system drains into veins in the neck
- Valves in lymph vessels prevent the backflow of fluid

Edema

swelling caused by disruptions in the flow of lymph

Lymph nodes

organs that filter lymph and play an important role in the body's defense
- When the body is fighting an infection, lymph nodes become swollen and tender

Blood in vertebrates is a _______ consisting of several kinds of cells suspended in a liquid matrix called _______.

connective tissue, plasma

Cells and cell fragments occupy about ______ of the volume of blood

45%

erythrocytes

Red blood cells, the most numerous blood cells
- They contain hemoglobin, the iron-containing protein that transports O2
- Each molecule of hemoglobin binds up to four molecules of O2
- In mammals, mature erythrocytes lack nuclei and mitochondria

Do erythocytes have nucli?

NO
they do not

leukocytes

white blood cells

What are the 5 different types of leukocytes? (White blood cells)

granulocytes (neutrophils, eosinophils, and basophils), monocytes, and lymphocytes (T cells and B cells).

They function in defense either by phagocytizing bacteria and debris or by mounting immune responses against foreign substances. They are found both in and outside of the circulatory system

Platelets

fragments of cells and function in blood clotting

Erythrocytes, leukocytes, and platelets all develop from a common source of...

stem cells in the red marrow of bones, especially ribs, vertebrae, sternum, and pelvis

The hormone erythropoietin (EPO)

stimulates erythrocyte production when O2 delivery is low

Cardiovascular diseases

disorders of the heart and the blood vessels
- These diseases range in seriousness from minor disturbances of vein or heart function to life-threatening disruptions of blood flow to the heart or brain

atherosclerosis

One type of cardiovascular disease, caused by the buildup of fatty deposits (plaque) within arteries
Cholesterol is a key player in the development of atherosclerosis

Low-density lipoprotein (LDL)

delivers cholesterol to cells for membrane production

High-density lipoprotein (HDL)

scavenges excess cholesterol for return to the liver

thrombus

A blood clot formed within a blood vessel, can block blood flow

myocardial infarction

A heart attack, is the damage or death of cardiac muscle tissue resulting from blockage of one or more coronary arteries

stroke

the death of nervous tissue in the brain, usually resulting from rupture or blockage of arteries in the head

Angina pectoris

chest pain caused by partial blockage of the coronary arteries

Hemophilia

blood doesn't clot

Risk factors of cardiovascular treatment

A high LDL/HDL ratio increases the risk of cardiovascular disease
- The proportion of LDL relative to HDL can be decreased by exercise and by avoiding smoking and foods with trans fats

Hypertension

High blood pressure, also contributes to heart attack and stroke, as well as other health problems
Hypertension can be controlled by dietary changes, exercise, and/or medication

Gas exchange

The uptake of O2 from the environment and the discharge of CO2 to the environment

O2 is much less_________ than in air. Per volume, there is less O2 available in _______ than in air

soluble in water, water

Obtaining O2 from water requires greater_______ than air breathing

efficiency

Gas exchange across respiratory surfaces takes place by _________

diffusion

Respiratory surfaces vary by animal and can include...

skin, gills, tracheae, and lungs.

Gills

out-folding of the body that create a large surface area for gas exchange

Ventilation...

moves the respiratory medium over the respiratory surface
Aquatic animals move through water or move water over their gills for ventilation.

countercurrent exchange

Fish gills use a countercurrent exchange system, where blood flows in the opposite direction to water passing over the gills

In fish gills, more than _____ of the O2 dissolved in the water is removed as water passes over the respiratory surface

80%,

Lungs

an in-folding of the body surface
- The circulatory system (open or closed) transports gases between the lungs and the rest of the body

The size and complexity of lungs correlate with an animal's....

metabolic rate

What conveys air to the lungs?

A system of branching ducts

Air inhaled through the nostrils is...

filtered, warmed, humidified, and sampled for odors

pharynx

directs air to the lungs and food to the stomach

Swallowing moves the ______ upward and tips the epiglottis over the glottis in the pharynx to prevent food from entering the ______, or windpipe

larynx, trachea

* Air passes through what to get to the alveoli, where gas exchange occurs

pharynx, larynx, trachea, bronchi, and bronchioles

Alveoli lack cilia and are susceptible to...

contamination

surfactants

Secretions that coat the surface of the alveoli

Preterm babies lack ________ and are vulnerable to respiratory distress syndrome; treatment is provided by _________.

surfactant, artificial surfactants

breathing

The process that ventilates the lungs, the alternate inhalation and exhalation of air

negative pressure breathing

How Mammals ventilate their lungs, which pulls air into the lungs

tidal volume

the volume of air inhaled with each breath
- The maximum tidal volume is the vital capacity

After exhalation, a residual volume of air remains in the lungs (True or false)

TRUE

medulla oblongata

The breathing control centers are found in this part of the brain
- The medulla regulates the rate and depth of breathing in response to pH changes in the cerebrospinal fluid

Breathing is regulated by _______ mechanisms

involuntary

Respiratory pigments

proteins that transport oxygen, greatly increase the amount of oxygen that blood can carry

Most vertebrates and some invertebrates use ________.
In vertebrates, this is contained within _________,

hemoglobin, erythrocytes

A single hemoglobin molecule can carry four molecules of O2, one molecule for each iron- containing heme group

Bohr shift

CO2 produced during cellular respiration lowers blood pH and decreases the affinity of hemoglobin for O2

Hemoglobin plays a ________ role in transport of CO2 and assists in buffering the blood
About _______ of CO2 from respiring cells diffuses into the blood and is transported in blood plasma

minor, 7%

The remainder diffuses into erythrocytes and reacts with water to form H2CO3, which dissociates into H+ and bicarbonate ions (HCO3-)

Deep-diving air breathers' stockpile CO2 and use it slowly (True or false)

FALSE
Deep-diving air breathers' stockpile O2 and use it slowly

myoglobin proteins

Deep diving breathers can store oxygen in their muscles in myoglobin proteins, Myoglobin is the reason your muscles are red

Diving mammals also conserve oxygen by...

- Changing their buoyancy to glide passively
- Routing blood to vital tissues
- Deriving ATP in muscles from fermentation once oxygen is depleted

Tympanic membrane

ear drum

Wax is important in your ear because...

it stops dust and allows water to exit the canal