Key concepts - exam Flashcards
List and describe the functions of blood
oTransportation
•O2, CO2, metabolic wastes, nutrients, heat and hormones
oRegulation
- helps regulate pH through buffers
- helps regulate body temperature
–coolant properties of water
–vasodilatation of surface vessels dump heat
•helps regulate water content of cells by interactions with dissolved ions and proteins
oProtection
•from disease and loss of blood
what is the composition of normal plasma and whats its function
- Plasma is the watery component of blood
- 91.5% water and 8.5% solutes
- Has plasma proteins, red cells, white cells, electrolytes, gases and other nutrients
Describe the process of erythropoiesis
oErythropoiesis: Erythrocyte formation, occurs in adult red bone marrow of certain bones.
oThe main stimulus for erythropoiesis is hypoxia.
•From anaemia, blood loss, circulatory problems.
oProcess:
oProerythroblast starts to produce Hb.
oReticulocyte is formed.
oReticulocytes leave bone marrow into the blood. (0.5% to 1.5% of RBC’s)
o In 1-2 days, they eject the remaining organelles to become a mature RBC.
List and describe the components of blood
oBlood consists of:
oplasma 55%
oformed elements 45% ( mostly RBC’s)
oBlood plasma consists of: 91.5% water and 8.5% solutes.
oPrincipal solutes include proteins (albumins, globulins, fibrinogen), nutrients, enzymes, hormones, respiratory gases, electrolytes, and waste products.
What are the formed elements of blood?
oRed blood cells (erythrocytes)
oWhite blood cells(leukocytes)
•granular leukocytes
–neutrophils, eosinophils, basophils
•agranular leukocytes
–lymphocytes = T cells, B cells, and Natural Killer cells
–monocytes
oPlatelets(Thrombocytes)
List the various leukocytes found in the blood
oBased on presence of cytoplasmic granules:
•Granulocytes:
–Neutrophils
–Eosinophils
–Basophils
Granules are made visible by staining
•Agranulocytes:
–Monocytes
–Lymphocytes
Neutrophil Function
o Fastest response of all WBC to bacteria
o Direct actions against bacteria
• release lysozymes which destroy/digest bacteria
Basophil Function
oInvolved in inflammatory and allergy reactions
oLeave capillaries and enter connective tissue as mast cells
oRelease heparin, histamine and serotonin
Eosinophil Function
o Leave capillaries to enter tissue fluid
o Release histaminase
• slows down inflammation caused by basophils
o Attack parasitic worms
o Phagocytize antibody-antigen complexes
Lymphocyte Functions
oB cells
- destroy bacteria and their toxins
- turn into plasma cells that produces antibodies
- Basis for Antibody Mediated Immunity
o T cells
- attack viruses, fungi, transplanted organs, cancer cells and some bacteria
- Responsible for Cell Mediated Immunity.
oNatural Killer cells
- attack many different microbes and some tumour cells
- destroy foreign invaders by direct attack
Monocyte function (agranulocyte)
Destroy microbes and clean up dead tissue following an infection
oMigrate from the blood into the tissues, enlarge and differentiate into macrophages
–fixed macrophages: Found in specific tissues
–wandering macrophages: Rome the tissues and gather at sites of infection
Take longer to get to site of infection, but arrive in larger numbers
Describe the 3 process for preventing blood loss
Haemostasis
oStoppage of bleeding in a quick and localized fashion when blood vessels are damaged
oMechanisms:
- Vascular spasm: Reflex contraction of smooth muscle of small blood vessels when arteries or arterioles are damaged.
- Platelet plug formation
- Blood clotting (coagulation = formation of fibrin threads)
Compare and contrast the extrinsic and intrinsic pathway
- Intrinsic pathway is activated by negative charges
- eg when endothelium of blood vessel is damaged
- after several minutes prothrombinase is produced
- Extrinsic is activated by trauma
- tissue factor (thromboplastin) release
- instant prothrombinase formation
- tissue factor (thromboplastin) release
Describe the Platelet Plug Formation process
o Platelet Adhesion
• platelets stick to exposed collagen and damaged endothelial cells in vessel wall
o Platelet Release Reaction
- platelets “activated” by adhesion
- extend projections & make contact
- release thromboxane A2, ADP, serotonin
o Platelet Aggregation
- activated platelets stick together to form a mass called a ‘platelet plug’
- plug reinforced by fibrin threads formed during clotting process
Describe the conduction pathways through the heart
o The conduction system in the heart is unique with autorhythmic cells derived from cardiac muscle.
- These cells act as a pacemaker to set the rhythm for the entire heart.
- They form the conduction system, the route for propagating action potentials through the heart muscle
oThis co-ordinates contraction of heart muscle.
What are the components of the condunction system of the heart ?
- Sinoatrial (SA) node (pacemaker),
- Atrioventricular (AV) node,
- Atrioventricular bundle (bundle of His),
- Right and left bundle branches,
- The conduction myofibers (Purkinje fibers)
Top and bottom of the heart are termed
top is base
bottom is apex
Discuss the flow of blood throughout via the major arteries and veins
chamber of the heart
- 2 upper atria and 2 lower ventricles
- seperated by interventricular and interatrial septum
- right atrium
- received blood from vena cava and coronary sinus
- tricuspid valve permits blood flow into right ventricle
- right ventricle
- blood flows into pulmonary trunk
- left atrium
- receives blood from lungs
- bicuspid valve for blood into left ventricle
- left ventricle
- aortic semilunar valve for blood to pass into ascending aorta
- right atrium
Describe the ECG and its components and its relationship to the cardiac cycle
oImpulse conduction through the heart generates electrical currents that can be detected at the surface of the body on the skin.
oA recording of the electrical changes that accompany each cardiac cycle (heartbeat) is called an electrocardiogram (ECG).
Define cardiac output
oCardiac output (CO) is related to how much the heart is pumping out (SV - stroke volume) and how fast it is going (HR)
oCardiac output (CO): the volume of blood ejected from the left (or right) ventricle into the aorta (or pulmonary trunk) each minute.
oCardiac output equals the stroke volume (the volume of blood ejected by the ventricle with each contraction) multiplied by the heart rate (the number of beats per minute).
•CO = SV x HR
List the factors that affect blood flow
- vascular resistance
- venous return (how much blood is returning to the heart)
- speed of blood flow
- blood pressure
chordae tendinae
- anchor valve to papillary muscles
- when ventricles relaxed, chordae tendinae are slack and papillary muscles are relaxed
- atrioventricular
- semilunar
- bicuspid
- tricuspid
*
Explain Baroreceptors
•baroreceptors (pressure receptors) detect change in BP and send information to the cardiovascular center
–located in the arch of the aorta and carotid arteries
List the factors that affect stroke volume
- Preload (filling/stretch) = Frank-Starling Law of the Heart
- increased filling = more stretch of the heart muscle
- leads to greater force of contraction
- contractility
- heart contracts harder
- sympathetic nerves, hormones, calcium or potassium levels
- afterload
- the pressure the heart must overcome before semilunar valve can open
- heart has to exceed BP to pump blood out
List the factors that affect heart rate
- hormones and ions
- adrenaline, noradrenaline, thyroid hormones
- cations eg Ca2+
- neural factors
- sympathetic or parasympathetic fibers, baroreceptors, chemoreceptors
- cardiovascular centre in medulla oblongata
- other factors
- age
- sex
- fitness
- temperature
Describe the mechanism involved on of antigen presentation by Antigen Presenting Cells
- Antigen presenting cells engulf foreign proteins and display some as part of the MHC-II
- phagocytosis/endocytosis of antigen followed by digestion
- synthesis and packaging of MHC-II molecules
- This process of presentation alerts T cells that foreign particles are present
Describe the Hb dissociation curve for O2.
- as PO2 increases, more O2 combines with hemoglobin
- PO2 of 60-100mmHg = 90% saturated
- PO2 of 20mm = 35% saturated
Describe the secretions and functions of the enzymes secreted by the pancreas
- pancreatic amylase
- digest starch
- pancreatic lipase
- digest triglycerides
- proteases
- digest proteins
- ribonuclease and deoxyribonuclease
- digest RNA and DNA
Describe the digestion and reabsorption of carbohydrates giving the location and enzymes involved as well as the end products
- mouth
- salivary amylase
- oesophagus and stomach
- no enzyme release
- small intestine
- pancreatic amylase
- brush border enzymes
Control of glomerular filtration rate
-
renal autoregulation
- when kidneys regulate GFR
- myogenic mechanism
- tubuloglomerular feedback
-
neural regulation
- when ANS regulates GFR
- Kidney blood vessels supplied by sympathetic fibers that release norepinephrine = vasoconstriction of afferent arteriole
- extreme sympathetic stimulation eg exercise = vasoconstriction to lower urine output
-
hormonal regulation
- involves angiotensin 2 and ANP
- ANP increases GFR
- angio 2 reduces GFR
Describe the function of the following hormones in controlling reabsorption of solutes and water
o Renin-Angiotensin-aldosterone system
- angiotensin 2
- increases sodium Na+, solute and water reabsorption
- = increased blood pressure and volume
- aldosterone
- increased secretion of potassium K+ and reabsorptin of sodium and chloride Cl-
- = increased reabsorp of water which increases blood pressure and volume
Describe the female reproductive cycle with reference to the hypothalamic, pituitary and ovarian hormones produced over a 28 day cycle.
- female reproductive cycle includes the ovarian and uterine cycles and hormonal regulations
- gonadotropin-releasing hormone released by hypothalamus which stimulates FSH and LH from anterior pituitary
- FSH (follicle stimulating hormone) stimulated follicle growth
- LH (luitenising hormone) stimulates further ovarian follicle development
- estrogens and progesterone from corpus luteum
- Over 28 day cycle
- see diagram
Describe the uterine cycle with reference to the menstrual, proliferative and secretory phases.
- Uterine cycle involves changes in the endometrium of the uterus to receive a fertilised ovum
- no implantation = stratum functionalis is shed (menstruation)
- estrogen release stimulates the proliferative phase when the stratum functionalis is beginning to be reproduced
- progesterone and estrogen stimulate secretory phase
