Exam 4 Flashcards
Compare and contrast nervous and endocrine system control
Nervous system - #1 controlling system of the body
- Neurons: release NTs
- Very fast, quick response by effectors
- Short-lived effect
Endocrine system - #2 controlling system of the body
- Glandular cells: hormones
- Lag time before response by target cells
* Hormone must travel through
bloodstream in order to reach
target cell
- Longer-lasting effect
- Both systems function in communication with other parts of the body
Contrast endocrine and exocrine
Endo = within
-crine = to secrete
Endocrine glands: hormones sent to target tissue through bloodstream
Exocrine lands: secretions sent through a duct to membrane surface
Give examples of endocrine glands
- Pineal gland
- Hypothalamus
- Pituitary gland
- Thyroid
- Parathyroid glands
- Thymus
- Adrenal
- Pancreas
- Ovary
- Testis
Contrast the 2 classes of hormones based on their structure
Amino acid based
- Composed of amino acids/derivatives
of amino acids
Steroid bases
- Made form cholesterol
- Examples: sex hormones and adrenal
cortex hormones (cortisol)
Define target cells
Cells with a receptor for a specific hormone that can respond to that hormone; the target of a hormone’s effect
Define receptor
(1) a peripheral nerve ending specialized for response to particular types of stimuli; (2) molecule that binds specifically with other molecules, e.g., hormones and neurotransmitters
Contrast the function of water-soluble and lipid-soluble hormones
Lipid-soluble/steroid hormones: can use direct gene activation or indirect
^ diffuse through the plasma membrane
to enter the target cell and bind to a
receptor protein.
Water-soluble/amino acid hormones: Indirect pathway
^ bind to a receptor protein on the plasma
membrane of the cell.
Contrast hormone mechanisms of action via direct gene activation and second messenger signaling
Direct gene activation
^ Steroid hormone (outside the cell)
^ Moves past plasma membrane and into cell through cytoplasm
^ Moves into nucleus
^ Binds receptor protein
^ Hormone-receptor complex interacts with DNA
^ Gene is turned on > mRNA transcribed > protein
Second messenger signaling
^ Hormone behaves as first messenger
(outside cell)
^ Binds membrane receptor, setting off a
chain reaction of events
^ After binding of receptor, enzyme
becomes active
^ Active enzyme then activates second
messenger (ex: cAMP)
^ Second messenger then has an effect on
cellular function, such as glycogen
breakdown
What are the three ways that the body controls the release of hormones
- Hormonal stimulus
- Humoral stimulus
- Neural stimulus
Describe the hormonal stimulus
- A gland secretes a hormone that then goes on to stimulate another gland to stimulate another hormone and so on – typically a 3-step pathway
^ Controlled by negative feedback
^ Ex: The hypothalamus secretes
hormones that stimulate the anterior
pituitary gland to secrete hormones that
stimulate other endocrine glands to
secrete hormones
Describe the neural stimulus
- Neural stimulus
^ Preganglionic sympathetic fiber
stimulates adrenal medulla cells to secrete
catecholamines (epinephrine and
norepinephrine)
Describe the humoral stimulus
- Humoral = blood
^ Capillary blood contains low
concentration of Ca2+, which stimulates
secretion of parathyroid hormone (PTH)
by parathyroid glands
What are the major anterior pituitary hormones/their functions and targets?
Hypothalamus also makes releasing hormones, such as GHRH and TRH, which then tell the anterior pituitary to release hormones such as…
- GH (growth hormone)
- TSH (thyroid stimulating hormone)
- ACTH (stimulates the adrenal cortex)
- FSH and LH (reproductive hormones,
stimulate the gonads = gonadotropins)
- PRL (prolactin)
What are the major hormones stored and released by the posterior pituitary and what are their functions?
- Oxytocin: causes uterine contraction during labor and targets mammary glands (milk let-down reflex)
- ADH: anti-diuretic hormone, targets kidney tubules, balances water in body
Describe the relationship between the hypothalamus and posterior pituitary as well as the hypothalamus and anterior pituitary
Hypothalamus and the posterior pituitary:
^ Hypothalamus is responsible for the
synthesis of oxytocin and ADH
^ Oxytocin and ADH are then
transported and released to the
posterior pituitary gland, where they are
stored until they are needed
^ The posterior pituitary does not
make any hormones on its own – it
simply stores and releases ADH and
oxytocin as needed and releases them
into bloodstream
Hypothalamus and anterior pituitary:
^ The anterior pituitary is under the
control of the hypothalamus
^ Hypothalamus also makes releasing
hormones, such as GHRH and TRH,
which then tell the anterior pituitary to
release hormones
_____ and _____ are the only non-endocrine targets of the anterior pituitary hormones
GH, PRL
Describe gigantism
Hypersecretion of GH in children (growth plates still open)
What is the function of GH?
- General metabolic hormone
^ Target cells increase in size and divide
^ Long bone growth
^ Increase in muscle mass - Effects on metabolism
^ Gat breakdown
^ Glucose sparing
^ Helps glucose stay in homeostasis
Describe acromegaly
Hypersecretion of GH in adults (growth plates closed)
^ Thickening of the bones, especially in
the face, hands and feet
Describe pituitary dwarfism
Hyposecretion of GH in children
^ Proportional limb sizes
What pathologies are associated with too much or too little GH?
Gigantism, acromegaly, pituitary dwarfism
What is/are the function(s) of thyroid hormone?
- Thyroid hormones inhibit anterior pituitary and hypothalamus
^ Negative feedback control - TH effects
^ Increases BMR
^ Increased glucose “burn” rate
^ Glucose energy to ATP
^ Responsible for heat production
^ Regulates tissue growth and
development (particularly important in
infants and children)
What is the location of the thyroid hormone?
Situated in the anterior part of the neck
^ Butterfly-shaped gland situated across the trachea
What are the major hormones of the thyroid gland?
Major hormones
- Thyroxine (T4)
^ Major hormone
^ 4 atoms of iodine
- Triiodothyroxine (T3)
^ Formed at target tissues
^ 3 atoms of iodine
- Calcitonin
^ Calcium deposit > bones
What is myxedema? What is it characterized by/what are the symptoms?
- Hypothyroidism in adults
- Unexplained weight gain, sluggish mentally and physically, low BMR, fatigued, cold
Describe the control of PTH
- Any time there is a blood-calcium imbalance/reduced amount of calcium ions, PTH steps in to correct this
^ PTH is stimulated by reduced calcium
ions
^ Signals sent to osteoclasts
^ Osteoclasts degrade bone matrix,
releasing calcium ions
^ Calcitonin = antagonist, works in
opposite way
^ Too much calcium ions > deposits
calcium in bones
High potassium levels would cause the release of…
aldosterone
What is cretinism? What is it characterized by/what are the symptoms?
- Hypothyroidism in infants
- Dwarfism, mental retardation, other developmental problems
- TH is screened in infants
What is goiter? What is it characterized by/what are the symptoms?
- Enlarged thyroid gland
- Often caused by iodine deficiency
- The body can’t make thyroid hormone, but the hypothalamus and anterior pituitary don’t know this, so they continue to signal for TH to be made and overstimulate the thyroid gland which then becomes enlarged
What is Grave’s disease?
- The most common kind of hyperthyroidism in adults
- High BMR, unexplained weight loss, hot, very agitated, tachycardia, exophthalmos (increased fluid behind eyes)
- Often due to tumor of thyroid gland > can be treated with radioactive iodine
What is the location of the parathyroid glands?
Posterior side of thyroid gland
What is the function of the parathyroid glands?
Makes parathyroid hormone (PTH)
^ Responsible for controlling blood calcium levels
What are the adrenal cortex hormones (3 different groups)
Aldosterone, cortisol, sex hormones (androgens)
Contrast hyper- and hypo parathyroidism
Hyperparathyroidism
^ Happens due to tumor or enlargement of one or more of the parathyroid glands
^ Too much PTH = too much calcium ion being released from bones, decreasing bone density > fractures
Hypoparathyroidism
^ Fatal
^ Blood calcium levels drop to a very low level
^ Muscle spasms, irritability are presenting symptoms
Describe the function of aldosterone and where it comes from
- The mineralocorticoid-secreting area of the adrenal cortex secretes aldosterone
- Aldosterone is responsible for sodium ion and water balance and blood pressure
^ Target: kidney tubules
Describe the function of cortisol and where it comes from
The glucocorticoid-secreting area of the adrenal cortex makes cortisone and cortisol
- Cortisol responds to stress by increasing blood glucose and blood pressure in an attempt to get you through the stressful situation
What produces the two pancreatic hormones? Are they under endocrine or exocrine function?
- Pancreatic islet cells
- Endocrine
What hormone is secreted by the pineal gland and what is its function?
- Responsible for sleep and wake cycles
- Produces and secretes melatonin
^ Peaks during the night
Define glycogenolysis and gluconeogenesis
- Glycogenolysis: converting glycogen to glucose
- Gluconeogenesis: making new glucose from non-carbohydrate sources (amino acids, etc.)
What are the two pancreatic hormones? Describe them
Alpha cells
- Produce glucagon in response to low
blood glucose
- Alpha cells would be stimulated if you
skip breakfast
- Stimulates: liver release of glucose
(stored as glycogen), glycogenolysis
(converting glycogen to glucose) and/or
gluconeogenesis (making new
glucose) > sends glucose to blood >
increased blood glucose!
Beta cells
- Insulin
- In response to high blood glucose
- Stimulates: cell membrane receptors
for glucose, liver storage of glucose
(glycogen)
Where is the adrenal medulla (compared to cortex) and what are its hormones and their functions?
- Inner portion of the adrenal cortex
- Responsible for short term stress response
- Makes epinephrine (adrenaline) and norepinephrine
^ Increased HR, increased BP, liberation
of glucose into bloodstream,
increased airflow via dilation of
bronchioles, etc.
^ Stimulated during fight or flight
Contrast type I and type II diabetes mellitus
Type 1: beta cells are destroyed
^ Autoimmune disease
^ Juvenile onset
^ Insulin dependent > must monitor
blood sugar levels and intake, must
administer insulin to make cells take up
glucose
Type II
^ Typically, adult onset
^ Resistant to insulin
^ In the beginning, beta cells are still
making insulin, but the receptors are
not sensitive to it/are resistant to it
^ Glucose in the bloodstream remains
high
Differentiate the components of blood in a centrifuged tube
- Plasma (yellowish, on top)
- Leukocytes/WBC, platelets (white band, interface between top and bottom layers)
- Erythrocytes/RBC (densest, at bottom layer, red)
Describe the composition of plasma; what protein is in the highest concentration and state the function of this protein
- About 55% of blood is plasma
- About 90% of plasma is water
- Salts (electrolytes) are found in plasma
- Most abundant plasma protein: albumin
^ Important for osmotic balance (keeps
osmolarity relatively high so that blood
volume is maintained) - Also contains fibrinogen (clotting factor) and globulins (defending antibodies)
What type of tissue is blood? Describe the composition
Connective tissue
^ Fluid matrix (plasma)
^ Bright red: high levels of oxygen
^ Dull red: low levels of oxygen
State the functions of blood
- Transport of substances
^ Nutrients: glucose, fatty acids, amino
acids, vitamins
^ Waste products of metabolism: urea,
uric acid
^ Respiratory gases: O2 and CO2
^ Hormones: steroids and thyroid
hormones are carried by plasma
proteins - Body heat distribution
Contrast the structure and function of erythrocytes and leukocytes
- Erythrocytes: RBCs, biconcave discs, very small, full of hemoglobin
^ Function is to transport oxygen and a
small amount of CO2 - Leukocytes: a round shape with a distinct center membrane (nucleus), colorless, appear light pink/purple under a microscope
^ Function is defense
Describe the process of erythropoiesis (see also the pathway later in the PPT), include the location and hormone/source of the hormone that regulates the process
- Erythropoiesis is the process of RBC formation
- Takes place in the red bone marrow (which makes all formed elements)
- Erythropoietin (EPO, hormone) comes from kidneys and stimulates erythropoiesis in response to reduced oxygen levels in the blood
- Stimulus (low blood O2)
- Kidneys (and liver, to a smaller extent) release erythropoietin
- EPO stimulates red bone marrow
- Enhanced erythropoiesis increases RBC count
- O2 carrying ability of blood increases
What are the stimuli for erythropoiesis?
Low blood O2
^ Decreased RBC count
^ Decreased amount of hemoglobin
^ Decreased availability of O2
It takes _____ days for a single RBC to reach maturity/pass through all developmental stages
3-5
Describe the structure and function of hemoglobin
- Structure: made up of 4 amino acid chains: 2 beta and 2 alpha globin chains
^ Heme group in center of each chain
where an iron atom can be found - Function: transporting oxygen from lungs to tissues through the blood, facilitates return of carbon dioxide
Define leukemia
Very elevated WBC numbers because the bone marrow has become cancerous, all are immature/non-functional in typical way
Define anemia. What can it be caused by?
- Reduced oxygen-carrying capability of blood
- Can happen due to reduced number of erythrocytes (hemorrhage, hemolysis, vitamin B deficiency) or reduced hemoglobin (iron deficiency)
Contrast the different types of anemia discussed in lecture
- Pernicious anemia: vit B deficiency
- Aplastic anemia: bone marrow is not producing adequate numbers
- Sickle cell anemia: genetically inherited disease, single amino acid change, sickle shape instead of normal biconcave shape, blood flow is blocked
Define positive chemotaxis
An attraction of WBC to areas of tissue damage/inflammation
Define leukocytosis
The increase in WBC number in response to infection or inflammation
State the overall function of leukocytes
Defense!
What is polycythemia and why is it a dangerous condition?
- An abnormal/excessive increase in RBC numbers
^ Could be cancer of the bone marrow
^ Could occur naturally in areas of high
altitude - Can be dangerous because it can cause the blood to become much more viscous and sluggish, leading to cardiac arrest
What are the two groupings of leukocytes? Contrast the structure
- 2 groupings: granulocytes, agranulocytes
- Granulocytes: granules in cytoplasm that carry inflammatory substances
- Agranulocytes: without granules
Define diapedesis
The passage of blood cells through the intact walls of the capillaries, typically accompanying inflammation
What are the types of granulocytes? Describe them
- Neutrophils: most abundant kind of WBC, have a multilobed nucleus, involved in acute infections, called bacteria slayers because they have a phagocytic function
- Eosinophils: bilobed nucleus, reddish-orange color when stained, elevation of eosinophils indicate the presence of parasitic worms and/or allergy attacks, shoot out digestive enzymes to kill parasitic worms
- Basophils: least numerous, bilobed nucleus, have very dark/coarse granules that make the nucleus hard to discern, stains dark blue, release histamine at sites of inflammation
Define leukopenia
An abnormally low WBC count, commonly caused by drugs
Define and know the 3 steps of hemostasis
- Hemostasis: stopping the blood
- 3 steps
- Vascular spasm
- Platelet plug formation
- Coagulation
^ Conversion of fibrinogen to fibrin
^ Fibrin meshwork = clot
What are the types of agranulocytes? Describe them
- Lymphocytes: smallest of all leukocytes, with the nucleus taking up almost all of the cell
*Two kinds: B (produce antibodies) and
T lymphocytes (involved in graft
rejection and in fighting tumors and
viruses via direct cell attack) - Monocytes: largest of the leukocytes, U-shaped nucleus, pale blue/grey color, macrophage, important for engulfing infectious agents as well as activating lymphocytes
What is thrombus?
When a clot persists in an undamaged vessel, blocking or occluding the vessel and anything downstream is robbed of blood
What is embolus?
Even more dangerous than thrombus, a travelling clot, can get lodged in smaller vessels like pulmonary or cerebral vessels
Know the 4 chambers of the heart, locations on a diagram and functions
- Upper chambers: atria
^ Reception: receive blood - Lower chambers: ventricles
^ Pumping chambers: pumps the blood
Outline the steps of hematopoiesis
In red bone marrow
- Hemocytoblast stem cells divide to form lymphoid stem cells and myeloid stem cells
- Lymphoid stem cells form lymphocytes
- Myeloid stem cells form erythrocytes, platelets, monocytes, neutrophils, eosinophils and basophils
ABO blood types are due to…
the presence of ABO antigens on surface of RBC
If you have type A blood, you are automatically making ______ antibodies
anti-B
Describe the Rh factor (D antigen, etc.)
- Rh factor: a separate antigen, either have it (Rh+) or don’t (Rh-)
^ Carry D antigen: Rh+
^ Lack the D antigen: Rh-
^ Reported together with ABO blood
type
^ No preformed anti-Rh antibodies - Rh- individuals must be sensitized (incorrect transfusion, pregnant mother who is Rh- but baby is Rh+ and blood mixes during delivery)
List the membranes covering the heart
- Serous membranes: 2-layered membranes
^ Parietal pericardium: lines the
pericardium on the inside
^ Visceral pericardium: covers the heart
If you have type A blood…
- What antigen do you make? Antibodies?
- From what blood type can you receive a transfusion? What blood type can you donate to?
- A-antigen, anti-B antibodies
- Can receive from A and O
- Can donate to A and AB
If you have type B blood…
- What antigen do you make? Antibodies?
- From what blood type can you receive a transfusion? What blood type can you donate to?
- B-antigen, anti-A antibodies
- Can receive from B and O
- Can donate to B and AB
If you have type AB blood…
- What antigen do you make? Antibodies?
- From what blood type can you receive a transfusion? What blood type can you donate to?
- A and B antigens, neither anti-A nor anti-B antibodies
- Universal recipient!
^ Can receive from AB - Can donate to AB
What blood type is the universal donor? Recipient?
- Universal donor: O
- Universal recipient: AB
If you have type O blood…
- What antigen do you make? Antibodies?
- From what blood type can you receive a transfusion? What blood type can you donate to?
- No antigens but both anti-A and B antibodies
- Can only receive from type O
- Universal donor because there are no antigens present!
^ Can receive from O
^ Can donate to AB
Describe the location of the heart within the thoracic cavity
- Situated off center, more over to the left side of the thorax
- Situated in the mediastinum (the middle portion of the thorax flanked by the lungs)
- Situated in its own pericardial cavity
- Covered by pericardium
Most abundant blood type in the US is type ___ and the rarest is type ___
O, AB
List the primary function of the CVS
Transport (of oxygen, nutrients, wastes, hormones)
List the layers of the heart wall (superficial to deep)
- Epicardium (same as the visceral layer)
- Myocardium
^ Thick cardiac muscle - Endocardium
^ Slippery inside of the heart, blood
rushes over this
Contrast the right and left ventricles (structure)
Left ventricle is much more muscular and thicker than the right ventricle, which has less myocardium
- Left ventricle has circular opening
- Right ventricle has crescent opening
Contrast the right and left ventricles (function)
- Right atrium receives oxygen poor blood from body
- Right ventricle then pumps the oxygen poor blood to the lungs from the pulmonary trunk
- Left side receives oxygen rich blood from the lungs
- Left ventricle pumps blood out through the aorta to the entire body
Contrast the right and left ventricles (function and structure together)
- Right ventricle is only pumping to the lungs, so it doesn’t need to be as strong as the left ventricle and doesn’t perform as much work
- Left ventricle is bigger and generates more force
Closing of ________ = “lub” sound
AV (atrioventricular) valves
Where is the aortic semilunar valve located?
Between left ventricle and aorta
Closing of ________ = “dub” sound
SL (semilunar) valves
What is the function of the chordae tendineae
Anchor AV valves
_______ create and maintain one way flow of blood
Heart valves
Describe the function/role of the papillary muscle
- Chordae are attached to papillary muscles
- Contract when ventricle is pumping blood, closing off the atria and preventing the backwards flow of blood
Tricuspid valve = _____ side
Bicuspid/mitral valve = _______ side
right, left
Describe the operation of the AV valves
- Blood returning to atria puts pressure against AV valves; the AV valves are forced open
- As the ventricles fill, AV valve cusps hang limply into ventricles
- Atria contract, forcing additional blood into ventricles
- Ventricles contract, forcing blood against AV valve cusps
- AV valves close
- Chordae tendineae tighten, preventing valve cusps from everting into atria
Describe the vena cava
- Superior vena cava: draining blood from head, neck and arms
- Inferior vena cava: draining blood from the trunk and the lower extremities
The pulmonary trunk splits off into…
- Left pulmonary artery
- Right pulmonary artery
^ Both send oxygen poor blood to lungs
Describe the function/role of the pulmonary semilunar valve
Involved in the carrying of blood to and from the lungs
Describe the operation of the semilunar valves
- As ventricles contract and intraventricular pressure rises, blood is pushed up against semilunar valves, forcing them open
- As ventricles relax and intraventricular pressure falls, blood flows back from arteries, filling the cusps of semilunar valves and forcing them to close
Describe the pulmonary veins
- Oxygenated blood returns to the heart via pulmonary veins
- All go into the left atrium!
Trace the pulmonary circuit
- Between heart and lungs
- Transport of oxygen-depleted blood from heart to lungs
- Oxygenation of blood in lungs
- Transport of oxygen-rich blood back to heart
Describe the coronary vessels
- Very narrow – some of the smallest arteries that we have
- If blocked > heart attack
- First, branch off of the aorta
- Tiny coronary arteries off of the lower portion of the aortic arch and deliver blood to the heart itself
- Cardiac veins pull the blood into the coronary sinus, which then delivers blood back to right atrium
- Heart takes care of itself first via the right and left coronary arteries/vessels
- Coronary veins carry waste and oxygen away from the heart
Trace the systemic circuit
- Between heart and body
- Oxygen rich blood pumped from heart to body
- Oxygen-depleted blood transported back to heart
Know the parts of the intrinsic conduction system of the heart and their functions
- SA node
^ Pacemaker of the heart
^ Wave of electricity goes to L and R
atria, causing them to contract - AV node
^ Wave of electricity moves to AV node
^ Wave of electricity then travels to AV
bundle, to bundle branches, to Purkinje
fibers - AV bundle/bundle of His
- Bundle branches (left and right)
- Purkinje fibers
- After all of this, the ventricles are stimulated/contract
- Heart contracts from the bottom up
Systole =
Diastole =
Isovolumetric =
- contraction
- relaxation
- the same volume (moments where all valves are closed, and heart is a closed system)
Describe all of the events of the cardiac cycle
- The cardiac cycle puts together the intrinsic conduction system as well as what’s going on with the blood, the opening and closing of the valves, etc.
- Entire cycle is all of the events that take place with one heartbeat
- The events of the cardiac cycle:
- Atrial diastole (ventricular filling)
- Atrial systole
^ Happens in conjunction with SA node
firing and when ventricles are ~75% full
^ Atria muscle contracts, forcing the
remaining blood into the ventricles
^ As pressure builds, we get to… - Isovolumetric contraction
^ Ventricles are beginning to contract,
closing the bicuspid and tricuspid
valves
^ Semilunar valves are not yet open >
no change in volume yet! - Ventricular systole (ejection phase)
^ Semilunar valves are open, blood is
ejected
^ Pressure drops, followed by the
closing of semilunar valves, leading
to… - Isovolumetric relaxation
^ AV valves not yet open again
^ Heart is relaxed
What is an ECG?
- Electrocardiography
- Measurement and recording of electrical activity of the heart, starting with the SA node
Describe the aorta
- Aortic arch has three branches, sending blood to head, neck and arms
- Descending aorta: delivers blood to the rest of the body
What is the first blip of an ECG?
- P wave
^ Atrial depolarization
^ Electrical event that leads to the
contraction of the atria
What is the second blip of an ECG?
- QRS wave
^ Ventricular depolarization
^ Electrical event that leads to the
contraction of the ventricles
^ Size differences between the two
ventricles is what causes the “funky”
shape of the wave
What is the third blip of an ECG?
- T wave
^ Ventricular repolarization
What is cardiac output (CO)?
How much blood each ventricle pumps out in 1 minute
What is stroke volume (SV)?
Volume of blood pumped out by a ventricle with each heartbeat (70 ml/beat)
How is CO calculated?
CO = HR x SV
As HR increases…
so does CO
As SV increases…
so does CO
What factors influence cardiac output?
- Stimuli
^ Crisis stressors (physical or emotional
trauma, increased body temperature,
exercise)
^ Low blood pressure
^ Exercise
^ Hormones - Inhibitors
^ High blood pressure or blood volume
^ Decreased blood volume
(hemorrhage)
Compare and contrast arteries, capillaries and veins (structure and function)
- Arteries: thicker walled vessels, has thicker tunica media, lined with epithelium, under higher pressure, recoil/have elasticity which helps them to move as pressure drops
- Veins: thinner walled vessels, lined with epithelium, under lower pressure (further from heartbeat), larger lumen, move blood against the force of gravity, have valves that maintain movement of blood
- Capillaries: capillary beds interact directly with tissues of the body, delivering oxygen and nutrients and pick up waste products, simple squamous epithelium surrounded by basement membrane, thin walled and highly porous
What is the lymphatic system? Describe its primary function
- Series of vessels that carries interstitial fluid (tissue fluid) back to the cardiovascular circulation and provides locations for immune cells to monitor the body
- Fluid must be returned for cardiovascular function to be maintained
Trace the route of lymph fluid after the interstitial fluid is picked up by lymphatic capillaries back to the heart
- Oxygenated blood leaves the heart via the left ventricle
- Moves through the aorta
- Out through all of the arteries to a particular tissue (arterial and venous side)
- Exchange happens here between capillaries and tissues!
- Fluid moves from capillary bed to lymphatic system
- Capillaries > lymph capillaries > lymphatic collecting vessels (valved) > lymph nodes (filter fluid) > lymph trunks (drain large regions of body), lymph ducts (drain the fluid back to veins)
Describe the structure of lymphatic capillaries and how the flap-like mini-valves function
- No opening on end (unlike blood vessels)
- Mini valves open and close in response to pressure
- Open when tissue fluid pressure is higher than the pressure inside of the vessel itself
- Made up of overlapping endothelial cells
- Anchored via collagen filaments to connective tissue
- Highly porous, very permeable
- Can take up bacterial cells and foreign debris
Describe the structure and function of lymph nodes
- Lymphatic vessels lead into and out of the nodes
- More afferent vessels (leading into) than efferent (going out) of the nodes
^ Fluid comes in and “hangs” for awhile
^ More time for lymph node to filter
everything! - Lymphocytes are housed in the lymph node
- Macrophage (monocytes) are also found in the node
^ Engulf and activate the lymphocytes
(T lymphocytes)
Where are the major clusters of lymph nodes in the body?
- Cervical lymph nodes: neck
- Axillary lymph nodes: arm pit
- Inguinal lymph nodes: groin
Contrast the right lymphatic duct and thoracic duct (location and what body parts each drains)
- Right lymphatic duct
^ Drains right side of the body
^ Right arm, right half of the thorax,
right side of the head and neck
^ Dumps into the right subclavian vein - Thoracic lymphatic duct
^ Drains left side of head and neck, left
thorax, left arm, abdomen and both
lower extremities
^ Drains more of the body than the
right lymphatic duct
^ Dumps into left subclavian vein
What veins (there are 2 intersecting) do the lymphatic ducts drain lymph into?
Right and left subclavian veins
Contrast the innate and adaptive immune defenses
- Innate (non-specific) defense mechanisms (1st and 2nd lines)
^ Inborn (ready at birth)
^ Immediate response
^ Examples: intact skin and mucous
membranes, secretions, inflammatory
response
^ Players: phagocytes, natural killer
cells - Adaptive (specific) defense mechanisms (3rd line of defense)
^ Mount an attack against 1 specific
type of foreign invader
^ Has memory!
^ Players: B and T lymphocytes,
macrophage, etc.
How does intact skin function in innate immunity?
- Physical barrier
^ Keratinized - Acidic pH
^ Acid mantle, reducing and inhibiting
many bacteria
^ Sebum and antimicrobial secretions
List the other organs of the lymphoid system discussed in lecture and briefly what each does
- Tonsils (in pharyngeal region)
- Thymus (in thorax; most active during youth, responsible for maturation of T lymphocytes)
- Spleen (curves around left side of stomach, filters blood and cleanses it, where RBCs go to die off)
- Peyer’s patches (in small intestines, help fight off organisms in digestive tract)
- Appendix (immunity/defense against organisms in large intestine)
How do intact mucous membranes function in innate immunity?
- Line any open body cavities
- Mucus
^ Moistens areas
^ Traps and keeps out foreign agents
(especially in respiratory tract) - Cilia
- Secretions
^ Stomach acid (HCl, destroys
pathogens)
^ Vaginal (acid mantle, protects against
bacterial and fungal growth)
^ Tears and saliva: lysozyme
How do phagocytes function in innate immunity?
- White blood cells
- Eat other cells!
- Types: neutrophils (most abundant WBC, bacteria slayers, increase in numbers in response to bacterial infection) and macrophage (large, engulf, digest, help T cells with memory)
How do antimicrobial chemicals function in innate immunity?
- Interferon
^ Interfere with viral infection
^ Work a lot like NK cells - Complement activation
^ Can limit bacteria or ramp up
immune system
^ Cascade of different steps
^ Last part of complement activation
results in a MAC formation (membrane
attack complex)
^ MAC pores in the membrane, allows
water to rush into the cell
^ This influx of water causes cell lysis!
How do NK cells function in innate immunity?
- Destroy foreign cells by lysing them
- Destroy specifically our own cells that have become virally infected and/or even tumor/cancer cells
- Can detect that our own cells aren’t quite right
- Nonspecific because they aren’t looking for a particular virus or bacteria
- Perforin (make holes in cells) and granzymes (move through holes and cause lysis of cells)
How does the inflammatory response function in innate immunity? What are the cardinal signs of inflammation?
- Damaged tissue cranks out inflammatory chemicals, which then draw (by positive chemotaxis) WBC to the area that is damaged
- Cardinal signs: redness, heat, pain, swelling/edema
How does a fever function in innate immunity?
- Systemic inflammatory response
- Pyrogens
^ Cause fever
^ Can be made by infecting organisms
or by our own body when it recognizes
a foreign organism
^ Enhances repair mechanism and can
limit bacterial growth
^ Moderate fevers are beneficial
What is an antibody?
What is produced by the B lymphocytes, circulate in the body neutralizing and/or targeting antigens
Define antigen. What can be an antigen?
- Molecules foreign to the body
- Provoke immune response
- Ex: non-self-substances: bacteria, fungi, viruses, pollen, foreign protein
Define systemic
The adaptive body defenses that go body-wide
What makes a molecule more antigenic?
Larger/more complexity
Define memory in terms of the immune system
- When the body remembers after an attack is launched and is able to fight more efficiently upon second contact
^ This is the basis of immunity!
What are haptens? Give an example
- Drugs and other smaller molecules that can trigger an immune response in some people (an incomplete antigen)
^ Ex: penicillin reaction
What are APCs? What do they do?
- Antigen presenting cells
- Detect foreign invaders and present them
Where do B and T lymphocytes develop and mature? What does maturation consist of (include immunocompetence here)
- Lymphocytes
^ Leukocytes
^ Originate from hemocytoblasts in red
bone marrow
^ Maturation: develop
immunocompetence (now competent
immune cells, able to fight off a specific
foreign agent)
^ B lymphocytes: mature in red bone
marrow
^ T lymphocytes: mature in the thymus
gland
Describe how the APCs work to stimulate the adaptive immune response
- Engulf and display fragments of foreign invaders (presentation of foreign invaders)
- APCs include dendritic cells, macrophage, B-lymphocytes
- Macrophage and dendritic cells present to T lymphocytes because they do not have the ability to recognize a foreign antigen
- T lymphocytes require presentation, B lymphocytes do not
- Activated B lymphocytes undergo clonal selection
^ Rapid division
^ Army of same B cell, now able to
recognize foreign invader
^ Become plasma cells
^ Circulate for 4-5 days and produce
specific antibodies
Define self-tolerance
- When the body checks to make sure that B and T cells will not react to “self-cells” or any self-antigens
- If any B or T cells recognize self-antigens, they are destroyed
^ This usually works
^ When it doesn’t > autoimmune
disease
Describe the humoral (antibody-mediated) immune response
- Mediated by antibody molecules that are secreted by plasma cells
- With assistance from helper T cells, B cells will differentiate into plasma B cells that can produce antibodies against a specific antigen
- The humoral immune system deals with antigens from pathogens that are freely circulating, or outside the infected cells
Know the basic antibody structure (IgG)
- Immunoglobulin type G
- Two heavy chains, two light chains
- Different portions = antigen binding sites
What are plasma cells?
Lymphocytes that go out to circulate in bloodstream, making huge amounts of antibodies
What are the mechanisms of antibody action?
Neutralization, agglutination, precipitation, antibody-antigen complexing (activates complement, activates/enhances inflammation)
Describe neutralization
- One of the most common ways antibodies work is through neutralization
^ Function to help us fight off a
pathogen
^ Antibodies bind all around the
outside of a virus, preventing the virus
from interacting with host cell
^ Enhances phagocytosis
Describe agglutination
- IgM
- Pentamer
- Binds cells together via antibodies
- Usually happens in mismatched transfusions
Describe precipitation
- Soluble antigens
- Antibodies bind antigens, bring it out of solution, and now phagocytes can come along and get them all at once
Describe antibody-antigen complexing activates complement
Membrane attack complexes, cell lysis
Describe antibody-antigen complexing activates/enhances inflammation
Increases blood flow and histamine release, more WBC to area, leading to the removal of antigen
Contrast passive and active humoral immunity
- Active immunity: naturally acquired through illness OR artificially acquired through vaccination
^ Actively fighting off pathogens - Passive immunity
^ Doesn’t last as long!
^ Natural: antibodies passed from
mother to fetus (placenta) and infant
(breastmilk)
^ Artificial: receiving immune serum
How do vaccines work to achieve immunity (artificial vs. naturally acquired immunity)
- Work very much like natural infections in terms of how they stimulate our immune system
^ Artificial immunity
^ Will not result in disease
^ Only receiving attenuated version of
disease that will not make you sick
How do helper T cells function?
- Recognize antigen presented by APCs
- Help activate B-lymphocytes and cytotoxic T-lymphocytes via signaling (cytokines)
^ B cells function at their best when
helper T cells activate them (but they
don’t need to be activated)
How do cytotoxic T cells function?
- Bind foreign cells
- Secrete granzymes and perforins
What is antigen presentation?
When macrophage or dendritic cells present bits of the foreign invader to T cells
How does the adaptive immune response result in memory for future attacks against repeat invaders?
- Second exposure
- Memory B and T cells are stimulated > swift and quick neutralization/destruction of pathogen
