Midterm #2 (Units 4,5,6) Flashcards
What is the series of tubes (blood vessels) connected to a pump (the heart)?
Vascular system
T or F: Blood is constantly moved through the system to all regions of the body, supplying blood cells with nutrients and gases
True
T or F: The vascular system not only delivers oxygenated blood to the organs but it also plays an important role in removing waste from our organs as well
True
What are the three parts of the circulatory system?
- A pump
- Carrying Vessels
- Small Vessel Networks and Capillary beds
T or F: Some exchanges happen in the capillary beds
False: ALL exchange happens in the capillary beds
What is the pump of the circulatory system?
The heart
What are the carrying vessels of the circulatory system?
- Arteries
- Arterioles
- Venules
- Veins
What does the term ‘atrium’ refer to?
refers to the cavity of the auricle
The fusion of 2 muscular pumps, the left and right side, each with an upper chamber (auricle) and lower chamber (ventricle): what am I?
The heart
The ____ have relatively thin walls compared with the ventricle walls.
Atria
T or F: The right ventricle is much thicker than that of the left ventricle
FALSE: The wall of the LEFT ventricle is much thicker than that of the right ventricle
T or F: Contraction of the ventricular muscle forces blood into the major arteries that lead away from the heart
true
Blood moves from major ____ leading into the atria.
veins
Contraction of the atrial muscles forces the blood through to the ______
ventricle
Define: Diastole
the period when cardiac muscles are relaxing to allow for filling of the atria and ventricles
Define: Systole
The period of atrial or ventricular muscle contraction (higher pressure)
What is our resting blood pressure?
120/80mmHg (systolic/diastolic)
What are the two types of flap-valves in the heart that prevent backflow of blood during contraction (systole) of ventricular muscles?
- Atrioventricular valve (AV)
2. Semilunar Valve (SL)
What are the two pacemakers in the body?
- Sinoatrial node (SAN)
- Atrioventricular node (AVN)
Cells of the _______ node spontaneously initiate action potentials that spread over the atria, this stimulates the ________ node to produce action potentials that pass along the Purkinje fibres and stimulate contraction of ventricles.
sinoatrial; atrioventricular
Direct delivers of the APs to the ventricles by the Purkinje fibres ensures that the chambers contract from the _______ ____
bottom up
Why do we need two pacemakers?
BC we need contraction to start at the bottom of the ventricle up
T or F: The heart does not need nerves to stimulate an action potential, its spontaneous
true
The rates of SAN excitation are governed by the _______ nervous system
autonomic
_______ from parasympathetic neurons slows the heart rate
Acetycholine
_______ from the sympathetic neurons speeds up the heart rate
Epinephrine
What is an ECG (electric cardio gram)
- waves of electric current measured on the surface of the skin
- surface recording- measure of all the electrical changes happening in the heart during one cardio cycle “Lub-Dub”
What is a “P wave”?
- the very first electrical change in heart
- initiated by the pacemaker
- depolarizes atria
What is the job of the “T wave”?
Ventricle relaxation/ ventricular repolarization
______ repolarization happens somewhere between Q and S- it is masked by the massive ventricular depolarization
Atrial
What is the main purpose of the heart?
Maintaining homeostasis- cares about blood pressure (how much volume you put into the system)
T or F: Blood pressure differs between species
False: Blood pressure remains the same throughout all species
What are the resting heart rates for rats, humans and elephants?
Rats: 500 beats/min
Humans: 60 beats/min
Elephants: 15 beats/min
Define: Cardiac Output
the amount of blood ejected by the heart over one minute.
- amount of blood expelled from the heart varies depending on the physiological need
- can be affected both by heart rate and by the volume of blood moved with each contraction
Define: Stroke Volume
- The volume of blood pumped by each ventricle in one contraction/ one heartbeat
- autoregulated
What are the short forms for heart rate and stroke volume?
HR= Heart Rate = beats/min
SV= Stroke Volume = L/contract (or beat) = L/min
CO (cardiac output) = HR x SV
What is Starling’s Law?
- the more cardiac muscle is stretched, the stronger the contraction
Discuss Heart Output
- systolic volume is largely regulated by the amount of blood returning to the heart via the major veins
- all of the blood returning to a healthy heart is pumped out in each cycle
- changing heart rate is the most common way to change cardiac output
What is happening in the body when there is congestive heart failure?
- ventricular muscle is weakened (poor blood supply)
- blood pools and the heart enlarges
- ventricular muscle is stretched and becomes weaker and the subject may eventually die
What are the three processes of the vascular system?
- carries blood away from the heart (arteries, arterioles)
- Exchanges occur between tissues and blood (capillary beds)
- Return blood toward the heart (venules, veins)
______ have a thick smooth muscle wall encased in a thick connective tissue sheath
arteries
As blood moves away from the heart it passes through successively smaller artery-like vessels, called __________.
arterioles
True or false: Arteries contain valves
False: arteries contain NO valves
True or False: Arteries carry oxygenated blood towards the heart.
False: Arteries carry oxygenated blood AWAY from the heart
_____ receive the blood that drains from the capillary beds
venules
_____ have thinner walls and less smooth muscle than arteries
veins
_____ carry deoxygenated blood towards the heart
Veins
What is the purpose of vascular valves?
- ensures blood moves towards the heart (prevents back flow)
- Contraction of skeletal muscle pressing on veins causes the displacement of the blood
What are the differences between blood vessels?
- arteries have thicker smooth muscle layer than veins
- capillaries are only one cell layer to allow for exchanges between blood and tissue
- veins have a thinner smooth muscle layer than arteries
What are capillary beds/exchange vessels?
- networks of thin-walled vessels in body tissues responsible for transfer of nutrients and waste products
What are the advantages of the small size of capillary beds?
- increased surface area
- makes for ideal diffusion conditions (moving from high to low concentrations)
What is a vascular shunt?
- directly connects venule without going through the capillary bed (bypass)
What is a true capillary?
-exchange vessel (oxygen, nutrients, carbon dioxide)
The flow through capillary beds is regulated by series of smooth muscle bands called _______ _______.
precapillary sphincters (PS)
What do precapillary sphincters do?
- encircle the root of each capillary; when they contract blood flow through that capillary is reduced or stopped
What are the two functions of the vascular shunt?
- normal exchange- blood passes through the capillary bed (Relaxed)
- Contracted- blood bypasses the capillary bed capillary vessels
The _______ circuit pumps blood from the right side of the heart to the lungs then returns blood to the left side of the heart.
pulmonary
The _______ circuit pumps blood from the left side of the heart to all parts of the body then returns blood to the right side of the heart.
systemic
What are the advantages of the double pulmonary/systemic circuit?
- two in-line pumps are needed in order to maintain sufficient and optimal blood pressure to push blood through the networks of the capillary beds
- the small diameter of the capillary beds imposes a high resistance to blood flow and this leads to a steep fall in blood pressure as blood flows through multiple capillary beds
______ carry oxygenated blood.
Arteries
_______ carry deoxygenated blood.
Veins
What is blood pressure?
- the force that moves blood through the closed circulatory system
What is vasoconstriction?
“closing” of vessels (increase in blood pressure)
- temperature induced response
What is vasodilation?
“opening” of vessels (decrease in blood pressure)
- regulated by the sympathetic division of ANS
What are the 4 ways small substances pass into and out of capillaries?
- Through the capillary cells (direct diffusion)
- Through clefts between capillary cells
- Through fenestrations (windows/pores) in the wall of the capillary (for larger and insoluble substances)
- Transferred in vesicles, by exocytosis and endocytosis
What two forces work against each other in the capillary exchange of fluids?
Hydrostatic pressure (BP) and osmotic pressure (proteins attract water from outside the capillary beds) work against each other.
Which system keeps water in homeostatic ranges?
Lymphatic system
Define: Edema
Fluid accumulation
List four biologically important substances that blood transports:
- Nutrients
- Nitrogenous waste products of metabolism
- Respiratory gases
- Many hormones
List three types of formed elements:
- Erythrocytes
- Leukocytes
- Platelets
What are erythrocytes?
- Red blood cells
- regulated by kidney
- most abundant group of cells
- for transport and delivery of respiratory gases
- regulated by metabolic rate of the individual
What are leukocytes?
- White blood cells
- regulated by colony stimulating factor and interleukins
- fundamental defence system
- located in lymphatic system, lymph nodes
What are platelets?
cell fragments
- important factors in the process of clot formation in wound repair
What are red blood cells?
- small disc-shaped cells
- major contributor to the viscosity of blood
- contain hemoglobin which gives blood its bright red colour
- do not contain a nucleus
What are the two types of leukocytes?
- Granulocytes
- Agranulocytes
What are the three types of granulocytes?
- Neutrophils
- Eosinophils
- Basophils
What do basophils do?
produce and release histamine as part of the inflammatory response
What do eosinophils do?
attack parasitic worms, fight infections
What are the two types of Agranulocytes?
- Lymphocytes
- Monocytes
What is hematopoiesis?
- blood cell formation
- come from common blood stem cell
- formed and reside in bone marrow
True or false: Erythrocytes wear out in 100 to 120 days
True
Define Hemostasis:
Stoppage of bleeding resulting from a break in a blood vessel
What are the three phases of homeostasis?
- Vascular Spasms
- Platelet Plug Formation (temporary blockage of blood flow in the injured area)
- Coagulation (blood clotting)
Role of platelets in hemostasis:
Undamaged blood vessel: platelets do not interact with the lining of the blood vessel
Damaged blood vessel: platelets respond instantly to exposed connective tissue and release chemicals onto their surface that makes them stick to the inner wall of the blood vessel
Why do we need body defences?
- the body is constantly in contact with bacteria, fungi, and viruses