Unit 4 Lecture Exam Flashcards
Cardiac muscle cells are held together end-to-end at complex junctions called ________ that consist of interdigitated membranes.
Intercalated disks
Within the junctions (intercalated disks) the cells are physically tethered by these strong connections that allow force created in one cell to be transferred to the adjacent cell.
Desmosomes
______ a component of Intercalated disks allow cardiac muscle cells to be electronically connected. These direct conduits between myocardial cells allow waves of depolarization to pass rapidly between cells causing them to contract almost simultaneously.
Gap junctions
These specific myocardial cells make up about 99% of the heart, are striated muscle, and have thick and thin filaments organized into sarcomeres
Contractile cells
These specific myocardial cells make up about 1% of the heart and mostly lack thick and thin filaments. Rather they are specialized for passing electrical signals around the heart.
Conducting cells (autorhythmic)
This general category of vessel directly returns blood back to the heart atria.
Veins
This general category of vessels directly receives blood from the heart ventricles
Arteries
These blood vessels are the primary site of vasoconstriction and vasodilation because they contain large amounts of smooth muscle
Arterioles
These blood vessel are where gas, nutrient, and waste exchange occurs in the body
Capillaries
These blood vessels receive deoxygenated blood from the capillaries
Venules
The circuit of the cardiovascular system that conducts deoxygenated blood from the heart to the lungs and returns oxygenated blood back to the heart is called the _____
Pulmonary circuit
The circuit of the cardiovascular system that conducts oxygenated blood from the heart to body tissues and returns deoxygenated blood back to the heart is called the
Systemic circuit
_____ defines the amount of blood that is pumped by one ventricle during a single contraction
Stroke volume
The total volume of blood pumped by one ventricle during a given period of time - typically one minuet - is called the _____
Cardiac output
This concept explains that the heart must pump all the blood that returns to it and the force of heart contraction is determined by the volume of blood returning to it at any given moment
Frank starling law
_____ is a term that describes all the electrical and physical events that happen in the heart during one contraction-relaxation cycle
Cardiac cycle
If we count the number of contraction-relaxation cycles that happen in one minute that defines a persons _____
Heart rate
The volume of blood entering the heart form the Venus circulation at any given moment is called _____
Venous return
_____ defines the volume of blood left in a ventricle at the end of its contraction phase
End-systolic volume
_____ defines the maximum amount of blood that a ventricle can hold when it is fully relaxed
End-diastolic volume
_____ describes the time when a heart chamber (atria or ventricles) are contracting and pumping blood
Systole
_____ describes the time when a heart chamber (atria or ventricles) are relaxing and filling with blood
Diastole
Which ion are funny If channels more permeable too?
Na+ ions (they are less permeable to K+ ions)
At the peak of the depolarization of a conducting cell, the funny If channels close and _____ channels open, resulting in the repolarization phase.
Slow K+ channels
When contractile cells receive a depolarization fro the adjacent conducting or contractile cell, they immediately depolarize through the opening of _____ channels.
Voltage gated Na+ channels
When the membrane potential reaches +20 mV channels for this ion open and close quickly, causing a very brief repolarization. For contractile cells action potential
K+ channels
What channels are open during the pacemaker potential segment of a conducting cell action potential
If (funny) channels
In the SA node the conduction action potential, what channel is open during the depolarization phase
Voltage gated Ca2+ channels
In the SA node conducting action potential the part of the action potential before the threshold is the _____. Is gets a special name to denote how it automatically climbs toward the threshold. What is that special name
Pacemaker potential
What is the resting membrane potential if contracting cells action potential
-90 mV
When contractile cells receive a depolarization from an adjacent conducting or contractile cell they immediately depolarize - Through the opening of these channels.
Voltage gated Na+ channels
When the membrane potential reaches +20mV stage in the contractile cells action potential this ion channel is open very quickly and closes very quickly. Causing a brief repolarization
K+ channel (creating the nubbin of the action potential)
The plateau of the contractile cells action potential is due to _____ channels opening. This ion moving into the cell leads to power strokes in the contractile less and sarcomere shortening.
Voltage gated Ca2+ channels
After the voltage gated Ca2+ channels close (in the contractile cell action potential) the cell will rapidly repolarize. This change in membrane potential is due to the opening of what kind of channels?
Slow K+ channels
Stats about oxygenated blood
- Higher O2 pressure and lower CO2 pressure.
- blood is coming back from the pulmonary circuit after getting oxygenated
-blood enters the left side of the heart through left pulmonary veins - oxygenated blood then is pumped out of the heart from the left ventricle to all body cells via the systemic circuit.
Stats about deoxygenated blood
- Lower O2 pressure higher CO2 pressure
- O2 is a nutrient for ATP production, so it gets deflected as the blood runs through the body
- CO2 is a waste product made in ATP
- deoxygenated blood is returning from the systemic circuit
- the right side of the heart receives the deoxygenated blood and then pumps the blood to the lungs via pulmonary circuit
What is the frank starling law
The heart must pump all blood that returns to it and it’s force of contraction is partially determined by how much blood returns to it (venous return stretching the sarcomeres)
The pulmonary circuit
From the right side of the heart to the lungs
Blood picks up O2 and drops off CO2
Returns to the left side of the heart
The systemic circuit
From the left side of the heart to all body cells
Blood drops off O2 and picks up CO2 and other metabolic wastes
Also distributes hormones, stored nutrients (glucose, triglycerides, etc) immune cells, and immunoglobulins around the body
Returns to the right side of the heart
What are the three portal systems in the body and what does that mean
Means that there are two capillaries that blood flows through in one circuit
1. Digestive system/liver
2. Kidneys
3. Brain
What are the components of the cellular matrix of blood
Red blood cells (erythrocytes), white blood cells (leukocytes) and platelets (thrombocytes)
What is in the liquid matrix of the blood
The liquid matrix is plasma
Contains: nutrients for atp, glucose, lipids, signal molecules (hormones/neurohormones) cytokines, immunoglobulins (antibodies)
What are cytokines
Signal molecules any nucleated cell can make. They are made on demand and released into the blood (immune ones sometimes)
Why are arteries the thickest?
They are closest to the left ventricle and need to handle the most pressure. They need to be strong and large in diameter. They have fibrous tissue that gives strength to the artery. They also have elastic tissue that gives stretchiness to the artery.
Stats about the makeup of arterioles
They have smooth muscle cells surrounding them allowing them to change in diameter. Smooth muscle cells in arterioles are the effector in total peripheral resistance.
The smallest and most delicate, very leaky, doe exchange of nutrients and waste pickup
Capillaries
What is the standard unit for liquid pressure (BP) and gas pressure
MmHg (millimeters of mercury)
What is needed for fluid to flow from one place to another
A pressure gradient, if there is no pressure gradient then there will be no flow in the system. The difference in pressure between two points on a vessel determines the flow rate (Volume per unit time)
_____ prevent back flow is pressure builds up on one end
One way valves
What vessels in the cardiac system have the most pressure
The pressure is at the highest closest to the left ventricle. Highest in the arteries and then lowest in the veins.
What are the two body pumps that help get blood back to the heart
The respiratory pump and the muscle pump
- the respiratory pump is pressure fluctuations during ventilation that push blood to the heart.
- the muscle pump is skeletal muscles that squeeze on veins with 1 way valves to aid in venous return.
The way we measure blood pressure is called _____. Also known as the pressure against the walls of a closed container. The force is exerted on the walls of the container by the fluid inside
Hydrostatic pressure
What do we use to measure blood pressure
And inflatable cuff and a sphygmomanometer
_____ is a blood pressure measurement that can be measured within the artery. It’s more invasive and is typically only done in surgery or extreme cases
Hydraulic blood pressure
What are the three factors that directly effect blood pressure
Total peripheral resistance
Cardiac output
Total blood volume
Total blood volume facts card
- the total volume in most adults is about 5L
- direct relationship with blood pressure. Increase in blood volume = increase in BP, decrease = decrease in BP.
- regulated very slowly by the urinary system. The effectors are the kidneys
- dehydration or water intoxication can change the volume of blood
What is the effector for total blood volume
Kidneys, in the urinary system
Total peripheral resistance facts card
- total peripheral resistance is: how hard your heart has to work to push blood through your blood vessels, also defined as the opposing force the heart must overcome to pump blood around the body.
- friction that your heart has to pump against. Blood cells bouncing off one another and off of the vessel walls.
- vasoconstriction = increase in per resistance (direct relationship) = increase in BP
- vasodilation = decrease in per. Resistance (inverse relationship) = decrease in BP
- smooth muscle cells on the arterioles are the effector for both
What is the effector for stroke volume
Contracting cells at the left ventricle
What is the effector for heart rate
Conducting cells at the sinoartial node
What are the three sub factors that effect total peripheral resistance
Vessel diameter, blood viscosity, and vessel length
These blood vessels have the smallest diameter. They are also the site of exchange for nutrients, wastes, and signal molecules between the blood and body tissues since they are composed only of a single layer of loosely connected endothelial cells
Capillaries
These blood vessels deliver blood to specific tissues and the smooth muscle cells embedded in their walls give them variable resistance. These characteristics make them ideal for fine tuning blood flow to meet the metabolic demands of different tissues around the body
Arterioles
These blood vessels collect blood just after is has had a chance to exchange nutrients, wastes, and signal molecules with body tissues and start its return journey to the heart
Venules
These blood vessels have the widest diameters and therefore hold more than help of the blood in our bodies. They also typically run close to the surface of our skin, so they must have both fibrous tissue for strength and elastic tissue for flexibility
Veins
These blood vessels are structurally reinforced with elastic and fibrous tissue, since they must withstand the highest blood pressures
Arteries
When considering blood pressure two values are always recorded. The _____ pressure represents the maximum pressure that occurs in an artery near the heart and follows ventricular contraction
Systolic
The _____ pressure represents the minimum pressure in an artery near the heart and coincides with ventricular relaxation
Diastolic
There are three main factors that determine your blood pressure at any given moment. One factor referred to as _____ focuses in how hard your heart is working at that moment. This factor combines the number of beats per minute and the volume of blood pumped per ventricular contraction, both of which are controlled by the autonomic efferent pathways
Cardiac output
Another key factor in determining blood pressure is the water content of the blood plasma. This factor is referred to as _____ and is regulated primarily by the kidneys with guidance from both autonomic and hormonal efferent pathways
Total blood volume
A third factor that influences your blood pressure, called____is determined by the variable diameter or radius of the arterials. This factor is mostly under tonic, sympathetic control and strategically divert more blood flow to hard-working areas and sends less blood flow to less-essential organs at any given time.
Total peripheral resistance
The skeletal muscles, liver, and heart muscle will receive more or less blood at times of exercise?
More
The digestive system, urinary system and reproductive organs will all receive mor or less blood flow during exercise?
Less
When high levels of nitric oxide is released as a paracrine signal molecule by neurons, that will cause _____ blood flow to those neurons
Increased