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
Vessels that…
- thinner walled, blood flows back to the heart mainly as a result of muscle contraction, valves to prevent back flow
- endothelium
- smooth muscle
- connective tissue
Veins
Velocity of blood flow is slowest in the _____________.
capillary beds
- high resistance
- large total cross-sectional area
- allows for exchange of materials
In capillary beds…
The area _______
The velocity_______
The pressure_______
Increases
Decreases
Decreases
Blood pressure is higher in arteries to help transport materials but as the blood pressure drops, the ____________ increases. At the venous end waste goes into the vessel due to this.
Osmotic pressure
Blood pressure is determined by _____________ and ______________.
Cardiac output
Peripheral resistance due to constriction of arterioles
- The pressure in the arteries during ventricular systole
- it is the highest pressure in the arteries
Systolic pressure
- The pressure in the arteries during diastole
- Lower than systolic pressure
Diastolic pressure
The rhythmic bulging of artery walls with each heartbeat
Pulse
What’s is a healthy blood pressure for a 20-year-old at rest?
120Mm Hg / 70 mm Hg
How is blood moved through veins?
- smooth muscle contraction
- skeletal muscle contraction
- expansion of the vena cava with inhalation
- One way valves in veins prevent backflow of blood
Blood flows through only _________% of the body’s capillaries at a time
Capillaries in major organs are usually filled to capacity
Blood supply varies in many other sites
5-10%
What are the two mechanisms that regulate distribution of blood into capillary beds?
- contraction of the smooth muscle layer in the wall of an arteriole to constricts the vessels
- Precapillary sphincters control flow of blood between arterioles and venules
Blood flow is regulated by nerve impulses, hormones, and other chemicals
The exchange of substances between the blood and interstitial fluid takes place across the ____________ of the capillaries
Endothelial wall
Most blood proteins and all blood cells are too large to pass through the endothelium.
True or false?
True
Contains sodium, potassium and other ions
- plasma proteins
- fibrinogen-to clot blood
- antibodies
Liquid portion of the blood
Plasma
Along with plasma what is blood composed of?
- red blood cells
- white blood cells
- platelets
- 90% water
- contains inorganic or organic substances dissolved or suspended in water
- plasma proteins (transport of substances,clotting, fighting disease) helps maintain blood volume and viscosity
Plasma
Where are red blood cells (erythrocytes) Made?
Red bone marrow
What do you mature red blood cells lack? What is the advantage?
Nuclei and mitochondria in mammals
This will leave more space for hemoglobin
Can bind up to 4 oxygen!*
- most numerous blood cells
- contains hemoglobin
Red blood cells (erythrocytes)
- Red iron containing pigment
- heme portion binds 02
- for molecules of O2
- carbon monoxide, a pollutant, can also bind at heme sites, can bee lethal and combines more regularly than oxygen
Hemoglobin
Red blood cells last around ______ days and then are destroyed in the __________ and __________.
120 days
Liver and spleen
What causes sickle cell disease?
Mutation in hemoglobin
- nucleated
- lack hemoglobin
- role is to fight infection and provide immunity
- five types
White blood cells (leukocytes)
White blood cells can be categorized into what two types?
Granulocytes- visible granules in cytoplasm (enzymes and proteins)
Agranulocytes-lack visible granules
- forms as a result of fragmentation of large cells in the red bone marrow
- involved in the process of clotting
Platelets
The steps of blood clotting…
- platelets form a plug for immediate stoppage of bleeding
- platelets and damaged tissue release prothrombin activator which requires calcium ions
- prothrombin activator activates the plasma protein prothrombin to thrombin
- thrombin converts fibrinogen to fibrin
- three threads of fiberin become interwoven into a patch clot, is composed of a network of fibrin threads in trapped cells
- as damage heals, plasmin breaks down the clot and restores fluidity of the plasma
- inherited disorder
- deficiency in a clotting factor
- internal bleeding can cause serious damage to cells and tissues
Hemophilia
Stem cells in the red marrow include…
- erythrocytes
- leukocytes
- platelets
- stimulates erythrocyte production when O2 delivery is low
- produced by the kidneys
Erythropoietin (EPO)
What helps maintain membrane fluidity? What are the two types?
Cholesterol
LDL- delivers cholesterol to cells for membrane production
HDL-scavenges cholesterol for return to the liver
-Hardening of the arteries by fat deposits
-plaque formation and vessels caused by fat and cholesterol
-plaques can cause clots to form thrombus
If clotbreaks loose it becomes a thromboembolism
Atherosclerosis
Heart attack is also called?
Myocardial infarction
Caused by partial blockage of the coronary arteries and results in chest pain
Angina pectoris
This is the pressure exerted by a particular gas in a mixture of gases
Partial pressure
What is respiratory mediums and respiratory services?
Animals can use air or water as a source of O2 for their respiratory medium
respiratory services include outer surface, skin, gills, trachea, and lungs
What two places in the respiratory system have cartilage rings?
Larynx and trachea
Functions are too warm air during inhalation, cleanser, humidifier. Contains odor receptors, tear glands drained into this…
Nasal cavity
- Connects nasal and oral cavities to larynx
- tonsils form a protective ring
- larynx and trachea are normally open
- esophagus is normally closed
Pharynx
- passageway for air between pharynx and trachea
- vocal cords(folds of mucosa that vibrate to make sounds, glottis opening between folds)
- epiglottis (prevents food from entering the respiratory tract)
The larynx
- connects larynx with primary bronchi
- supported by C shaped cartilage rings
- Cilia sweep mucus towards the pharynx (smoking can destroy cilia)
Trachea
The right lung has ______ lobes and the left lung as _____ lobes.
Each lobe is divided into ___________
3, 2
Lobules
Lobule has a __________ serving many alveoli
Lungs are covered by a serous membrane called…
Bronchial
Pleura
Right and left primary ___________ resemble trachea in structure
Branch to secondary bronchi that eventually lead to bronchioles
Each bronchiole leads into alveoli
Bronchi
The __________ Direct air to the lungs in food to the stomach.
Swallowing tips the epiglottis over the glottis in the pharynx to prevent food from entering the __________.
Pharynx
Trachea
- cilia and mucus line the epithelium of the air ducts and move particles up to the ____________
- this “ mucus escalator” cleans the respiratory system and allows particles to be swallowed into the esophagus
Pharynx
Where does gas exchange take place in the respiratory system?
The Alveoli, Air sacs at the tips of bronchioles
Oxygen diffuses through the moist film of the epithelium and into capillaries
Carbon dioxide diffuses from the capillaries across the epithelium and into the air space
Alveoli lack _______ and are susceptible to contamination
Secretions called __________ coat the surface of the alveoli
Preterm babies like this
Cilia
Surfactants
Is respiration active or passive?
Is expiration active or passive?
Active (intercostal muscles move up and out, negative pressure, diaphragm contracts and moves down)
Passive
Mammals ventilate their lungs by ____________ pressure breathing, which pulls air into the lungs
*** negative
The volume of air inhaled with each breath
About 500ml at rest
Tidal volume
The maximum tidal volume
Vital capacity
Air that remains in the lungs after exhalation
Residual volume
What acts on the phrenic nerve to cause diaphragm to contract?
What inhibits it?
Pons
Vegus nerve
Regulates the rate and depth of breathing in response to pH changes in the cerebrospinal fluid
Adjust breathing rate and depth to match metabolic demands
Medulla oblongata
What exerts secondary control over breathing?
Sensors in the aorta and carotid artery‘s monitor O2 and CO2 concentrations in blood
When CO2 increases, the blood pH lowers due to carbonic acid
Blood arriving in the lungs has a low partial pressure of _______ and a high partial pressure of ______ relative to air in the Alveoli
O2, CO2
In the Alveoli, 02 diffuses into the blood in CO2 diffuses into the air
In tissue capillaries, partial pressure gradients favor diffusion of O2 into the interstitial fluid and CO2 into the blood
Arthropods in many Molluscs have ____________ with __________ as the oxygen binding component
Hemocyanin, copper
A single hemoglobin molecule can carry _____ molecules of O2
Each molecule for each iron containing heme group
4
CO2 produced during cellular respiration lowers blood pH and decreases the affinity of hemoglobin for O2
- hemoglobin is able to release more oxygen
Bohr shift
Along with oxygen, hemoglobin also helps transport _______ and assists in buffering the blood
CO2
CO2 from respiring cells diffuses into the blood and is transported in blood plasma, bound to hemoglobin, or as bicarbonate ions (HCO3-)
Most CO2 is carried as ________________ ions
_________________ catalyzes the breakdown of carbonic acid
Bicarbonate
Carbonic anhydrase
When hemoglobin picks up oxygen it becomes ____________
Oxyhemoglobin
Most CO2 combines with H2O. What speeds up the reaction?
Carbonic anhydrase
The osmolarity of the urine is regulated by nervous and hormonal control
The permeability of collecting duct is under ___________ control
Hormonal
An increase in osmolarity triggers the release of __________, which helps to conserve water
ADH
