Chapter 32 & 33 Biology: Circulation and Cardiovascular Systems

how do unicellular protists obtain oxygen and nutrients from their aqueous external environment?

simple diffusion

how do cnidarians and flatworms complete circulation?

their cells are directly exposed to either the external environment or to a gastrovascular cavity that functions in both digestion and circulation

how do echinoderms complete circulation?

fluid in their body cavity distributes oxygen and picks up wastes

why is the hydra able to execute circulation through diffusion?

because the animal is so simple and thin, every cell is close enough to the cavity that diffusion alone can distribute what’s needed

how and why are flatworms able to execute circulation through a gastrovascular cavity?

their gastrovascular cavity is highly branched, ensuring that no cell in the body is ever too far away from the cavity, so diffusion can still do the job without a circulatory system

what is the relationship between an organisms size and its circulation?

as animals get larger and more complex, diffusion and cavities are no longer enough and a dedicated circulatory system becomes necessary

circulatory system

an organ system that transports materials like oxygen and CO₂, sugars, amino acids, fatty acids, waste products, and immune cells

open circulatory system

• no distinction between blood and the extracellular fluid of the body tissues

• works through hemolymph fluid

• found in mollusks (e.g. clams) and arthropods (e.g. grasshoppers)

• blood is not enclosed in vessels and directly reaches organs and cells

closed circulatory system

• blood is transported within blood vessels

• the blood is pumped by the heart

• all vertebrates have this type of circulatory system (but not limited to)

• blood and extracellular fluid is seperate

what are the types of transportation?

• respiratory

• nutritive

• excretory

respiratory transportation

the action of erythrocytes carrying oxygen from the lungs/gills and carbon dioxide to the lungs/gills

nutritive transportation

• nutrients being absorbed through the intestinal wall into the blood in the blood vessels

• blood carries these absorbed products of digestion to the cells of the body

excretory transportation

metabolic wastes, excessive water and ions, and other molecules in plasma being filtered by the kidneys and excreted in urine p

plasma

• the fluid portion of the blood

• complex solution of water with metabolites, wastes, salts, ions, and proteins dissolved within it

what types of regulation occur in the body?

hormone transport and temperature regulation

hormone transport

blood carries hormones from endocrine glands to organs b

how is temperature regulated in warm blooded vertebrates?

blood vessels just under the epidermis constrict or dilate based on the temperature

what evolutionary adaptation has been made to regulate temperature in warm blooded vertebrates?

• in cold temperatures, superficial vessels constrict allowing more blood to the core of the body to prevent heat loss

• in warm temperatures, superficial vessels dilate allowing more blood to surface of the body to release heat

through what methods is the body able to protect itself?

blood clotting and immune defence

what does blood clotting do?

protects against blood loss when vessels are damaged

how does immune defense work in the body?

some leukocytes produce antibodies (proteins that fight infection), do phagocytosis, release inflammation, and fever

hemolymph

the circulatory fluid in invertebrates with open circulatory systems

which three parts make up a vertebrate circulatory system

• the heart

• the blood vessels

• the blood

the heart

a muscular pump that pushes blood through out the body

blood vessels

a network or tubes through which the blood moves

the blood

circulates through the blood vessels

what is the pathway of blood vessels?

1. blood leaves the heart through arteries

2. blood travels to arterioles (smaller arteries) to capillaries

3. blood exchanges gases and metabolites (e.g. glucose, vitamins, and hormones) with the cells of the body in the capillaries

4. the blood leaves the capillaries and passes into the venules (small veins) to the veins

why are arteries more sturdy than veins?

because blood is coming from the heart under high pressure

what is the structure of an artery?

• outer layer is made out of fibrous connective tissue

• middle layer is made out of smooth muscle and elastic tissue

• inner layer is made out of endothelium

• thicker walls

what is the structure of a capillary?

1 endothelium cell thick

what is the structure of a vein?

• outer layer is made out of fibrous connective tissue

• middle layer is made out of smooth muscle and elastic tissue

• inner layer is made out of endothelium

• thinner walls

how does a capillary bed function?

• O₂ rich blood flows into the artery and branches off into arterioles

• blood mixes

• blood enters the venules and branches into a vein, resulting in O₂ poor blood out

what are the characteristics of erythrocytes?

• carry hemoglobin proteins that transport oxygen and CO₂

• lack a nucleus (still eukaryotic because they lose a nucleus only after they mature)

what are the characteristics of leukocytes?

• several types

• immune defenses involved in defending the body from infection and cancer

• have a nucleus

what are the characteristics of platelets?

• play a key role in blood clotting

• contain no nuclei

what is the composition of blood?

• 45% of formed elements

• 55% of plasma

what kind of organisms have a four-chambered heart?

mammals, birds, and crocodilians

what are the main pumping portions of the heart?

ventricles

how are blood vessels color coded?

• red = O₂ rich arteries

• blue= O₂ poor veins

what are the two circuits of the heart?

• pulmonary (links heart to lungs)

• systemic (links heart to rest of the body)

pulmonary circuit pathway

1. superior and inferior vena cavae (oxygen poor blood)

2. right atrium

3. tricuspid valve

4. right ventricle

5. pulmonary semilunar valve

6. pulmonary arteries

7. lungs (capillaries)

8. pulmonary veins (oxygen rich blood)

9. left atrium

systemic circulation

1. left atrium (oxygen rich blood)

2. bicuspid valve

3. left ventricle

4. aortic semilunar valve

5. aorta

6. arteries

7. capillaries in tissues

8. veins (oxygen-poor blood)

9. superior and inferior vena cavae

10. right atrium

which side of the heart has oxygen poor blood?

right

nodal tissue

a specialized cardiac muscle that has both muscular and nervous tissue responsible for generating and conducting electrical signals that initiate contractions

sinoatrial node

• the pacemaker

• the site where each heartbeat (contraction) originates by a wave of depolarization (electrical signal)

what is the sequence of depolarization?

• the wave of depolarization originates at the SA node

• the wave of depolarization passes over the right and left stria causing their contraction

• the wave of depolarization reaches the atrioventricular (AV node)

• the AV node passes the wave to the ventricles through the bundle of His

• the depolarization is conducted rapidly over the surface of ventricles by the Purkinje fibers

atrioventricular (AV) node

a node located in the right atrium responsible for creating a delay allowing for optimal ventricular filling

purkinje fibers

specialized fibers located in the inner ventricular walls responsible for spreading the electrical impulses radiated from the AV node

what is the bpm of the average human heart

70

lub

• first sound (longer and lower)

• closing of tricuspid and bicuspid mitral valves (atrioventricular valves)

• blood leaving atria

dub

• second sound (shorter and sharper)

• closing of the pulmonary semilunar and aortic semilunar valves

• blood leaving ventricles

murmers

valves not closing correctly

diastolic pressure

• when the atria are filling, pressure in artery is low

• ideally 80

systolic pressure

• when ventricles contract, pressure in artery is high

• ideally 120

EKG or ECG

• electrocardiogram

• monitors electrical signal through the heart

P wave

• first part of an EKG

• represents the electrical signal spreading through the atria, triggering them to contract and push blood down the ventricles

• small wave because the atria are smaller chambers

QRS complex

• represents the electrical signal spreading through the ventricles, triggering them to contract

• prior to the actual ventricular contraction

T wave

the recovery period for the ventricles

myocardial infarction

• heart attack

• portion of heart muscle dies due to not receiving enough oxygen from the coronary artery

  • caused by atherosclerosis

angina pectoris

chest pain due to inadequate blood supply to the heartst

stroke

• blocked blood supply in brain

• brain cells die due to lack of oxygen

atherosclerosis

fat and cholesterol crystal accumulation in arteries

arteriosclerosis

• hardening of the arteries

• often goes hand in hand with atherosclerosis

hypertension

• high blood pressure

• often caused by narrowing the arteries due to atherosclerosis

fish circulation system

• a modified tube consisting of four chambers

• one circulation (circut)

oxygenated blood pathway in fish circulatory system

1. gills

2. arteries

3. body

4. veins

5. heart

6. gills

amphibian circulation system

• amphibians have a three chambered heart consisting of two atria and a ventricle

• have a pulmonary and systemic circuit

reptile circulation system

• have a three chambered heart consisting of two atria and a partially divided ventricle (except the crocodilians)

• have a pulmonary and systemic circuit

mammalian and bird circulation system

• mammals, birds, and crocodilians have a four chambered heart consisting of two atria and two ventricles

• two circulations

the lymphatic system

• returns fluids that leak through the capillaries to the circulatory system

• consists of lymphatic vessels and capillaries, lymph nodes, and lymphatic organs

functions of the lymphatic system

• returns proteins to the circulation

• transports fat absorbed from the intestine

• aids in the body’s defense through the leukocytes gathered in lymph nodes