Chapter 42: Circulation and Gas Exchange Flashcards
All animals have a circulatory system.
True or false?
False
Some animals lack a circulatory system
Some _____________ have functions in both digestion and distribution of substances throughout the body
-two cells thick
Cnidarians
Flatworms have a ____________ cavity and flat body.
Gastrovascular
Do planarians have a circulatory system?
No
Three major components of the circulatory system…
- circulatory fluid
- set of interconnected vessels
- heart
What’s The circulatory fluid in open circulatory systems called?
Hemolymph
What is an open system?
Blood is not always in the blood vessels, ends up in the body cavities directly bathing the organs. When the heart relaxes it draws the hemolymph back in the pores and valves.
What are the advantages of an open and closed circulatory system?
Closed- this system helps organisms that move quickly. It’s more efficient at transporting circulatory fluids to tissues and cells
Open-uses less energy
In a close circulatory system, blood is confined to the vessels and is distinct from the ___________.
Interstitial fluid
Examples of open and closed systems?
Open- insects, other Anthropods, and most Mollusca
Closed- annelids, cephalopods, and vertebrates
Arteries and veins are distinguished by….
Not by O2 content
The direction of blood flow
Not all arteries carry oxygenated blood
The site of chemical exchange between the blood and interstitial fluid*
Nutrient and gas exchange
Capillary beds
What type of circulation does the blood pressure drop significantly?
Single circulation
Bonnie fishes, rays, and sharks have ___________ circulation with a ______________ heart. ***
Single
Two chambered heart (one atria and one ventricle)
In single circulation, blood leaving the heart passes through __________________ before returning
Two capillary beds.
Gill capillaries and body capillaries
Oxygen poor and oxygen rich blood are pumped separately from the right and left sides of the heart. pulmonary and systemic circuit
Type of circulation seen in amphibians, reptiles, and mammals
Double circulation
In reptiles and mammals, oxygen poor blood flows from the pulmonary circuit to pick up oxygen through the lungs
In amphibians, oxygen poor blood flows through a ______________ circuit to pick up oxygen through the lungs and skin
Pulmocutaneous
-Oxygen rich blood delivers oxygen to the systemic circuit
Double circulation maintains _________ blood pressure in the organs then does single circulation
Higher
How many chambered heart do amphibians have?
3
2 atria and 1 ventricle
There is some mixing of blood but there are ridges in the ventricle that help keep deoxygenated and oxygenated blood from mixing too much
In amphibians, The ventricle pumps blood into a _______________ that splits the ventricles output into the pulmocutaneous circuit and the systemic circuit
Forked artery
What’s the advantage of amphibians having one ventricle?
They can pick up gases when underwater through the skin
Blood flow to the lungs is nearly shut off
How many Chambers do reptiles have?
3 Chambers
2atria, 1 ventricle
They have an incomplete septum, so they can create a complete shunt when underwater
There is less mixing in the heart compared to amphibians, Can block pulmonary circuit
Reptiles have _______________, with a pulmonary circuit (lungs) and a systemic circuit
Double circulation
The aorta provides blood to the heart through the ____________ arteries
Coronary
What vessels take deoxygenated blood to the lungs?
Pulmonary arteries
What vessels take oxygenated blood to the left atrium?
Pulmonary veins
The heart contracts and relaxes in a rhythmic cycle called the…
Cardiac cycle
Systole(contracting) and diastole (relaxing or filling phase)
Also known as pulse or the number of beats per minute
About 70 beats per minute
Heart rate
The amount of blood pumped in a single contraction
Stroke volume
The volume of blood pumped into the systemic circulation per minute and depends on both the heart rate and stroke volume
About 5 liters a minute?
Cardiac output
What sound is made from the recoil of blood against the arterioventricular valves when they close ?
“Lub”
What sound is made from the recoil of blood against semi lunar valve’s that close?
“Dub”
Some cardiac muscles are ______________, meaning the contract without any signal from the nervous system
Self excitable
What muscles causes the contraction of ventricles?
Perkinjie
Set the rate and timing at which cardiac muscles contract
In the wall of the right atrium
Also known as the pacemaker
Slight delayed to allow complete emptying
Sinoatrial (SA) node
What initiates the heartbeat, it sends out an excitatory impulse every .85 seconds
SA node “pacemaker”
- located at the base of the right atrium wall
- when impulses (that originated in the SA node) reach the _________, there is a slight delay that allows the atria to finish their contraction
- an impulse then travels through the branches of the atrioventricular bundle before reaching the Purkinje fibers
AV (atrioventricular) node
Specialized muscle cells that cause the ventricles to contract
Purkinje fibers
Intrinsic control of the heart beat….
Extrinsic control of the heartbeat…
-The SA and AV node
- autonomic nervous system
- hormones
- temperature
How does the autonomic nervous system Control the heartbeat?
Sympathetic system-increases heart rate, speeds up the pacemaker
Parasympathetic system-decreases SA and AV nodal activity, slow down The peacemaker to decrease heart rate when we are inactive
Besides the autonomic nervous system, what are two other factors that have extrinsic control of the heartbeat?
Hormones such as epinephrine
Temperature, and increase in 1°C can increase the heart by 10 bpm
A vessels cavity is called the _______________.
What are the vessels structure?
Central lumen
- endothelium (epithelial player that lines blood vessels)
- smooth muscle
- connective tissue
Vessel that….
- has thin walls
- The endothelium plus it’s basil lamina, to facilitate the exchange of materials
Capillaries
Vessel that….
- has the thickest walls to accommodate the high pressure of blood pumped from heart
- endothelium
- smooth muscle
- connective tissue
Arteries