Human Systems Flashcards
Types of Invertebrate Circulation
1) No circulatory system
2) Open circulatory system
3) Closed circulatory system
No circulatory system
– use simple diffusion
to distribute nutrients. Includes bacteria,
protista, fungi, invertebrate animals.
Open circulatory system
– pumps fluid called hemolymph into sinuses or hemocoel. Includes some mollusca, arthropoda, Echinodermata.
Closed circulatory system
– Use a pumping heart to move blood through vessels. Includes annelida (earthworms)
Vertebrate Circulation
- Most chordates (eukaryotic vertebrates within
kingdom Animalia) have a closed circulatory
system. Blood is a type of connective tissue due to containing cells surrounded by a matrix.
2-chambered hearts (atrium and ventricle)
– fish. Deoxygenated blood fills the heart and is pumped to the gills for oxygen exchange.
3-chambered hearts (2 atriums and 1 ventricle)
– amphibians and reptiles. Poikilothermic chordates. Alligators and crocodiles are exceptions, they have 4-chambered hearts.
4-chambered hearts (2 atriums and 2 ventricles)
– birds and humans. Homeothermic chordates.
Human Heart - Flow of blood through heart
- Right atrium – Deoxygenated blood is returned here from the upper superior vena cava and the lower inferior vena cava. Blood passes through the right atrioventricular valve (AV valve, or tricuspid valve) to the right
ventricle. AV valve is attached to papillary
muscles, which contract to close the AV valves
and prevent backflow of blood. - Right ventricle – Pumps deoxygenated blood through the pulmonary semilunar valve to the pulmonary artery. Blood enters pulmonary circulation. When the ventricle contracts, the AV valve is closed and the pulmonary semilunar valve is open. When the ventricle relaxes, the AV valve is open to refill the ventricle, and the pulmonary semilunar valve closes to prevent the backflow of blood.
- Left atrium – Oxygenated blood is returned
here from the lungs from the pulmonary vein.
Blood passes through the left AV valve (or
bicuspid, or mitral valve) to the left ventricle. - Left ventricle – Most muscular chamber of
the heart. Pumps oxygenated blood into the
aorta and systemic circulation.
Pulmonary circulation
- moves deoxygenated blood from heart to the lungs and back in order for it to become oxygenated.
Pathway of pulmonary circulation
- Right atrium → tricuspid valve → right ventricle → pulmonary semilunar valve →
pulmonary arteries → lung → pulmonary veins → left atrium
Systemic circulation
- moves oxygenated blood
from the heart throughout the body.
Pathway of Systemic circulation
Left atrium → bicuspid / mitral valve → left
ventricle → aortic semilunar valve → aorta → body → vena cava → right atrium
Human Cardiac Cycle
- The heart needs to contract and relax rhythmically in order to pump blood throughout the body. Cardiomyocytes (heart muscle cells) have automaticity, which means they are self-excitable and able to initiate an action potential without an external nerve.
1) SA Node
2) AV node
The SA node (pacemaker)
- is located in the upper wall of the right atrium and usually initiates the cardiac cycle. It has the greatest automaticity and is most likely to reach threshold to stimulate a heartbeat. It sends a signal to contract both atria to send blood to the ventricles. It also sends a signal to the AV node to initiate contraction.
The AV node
- is located in the lower wall of the
right atrium. The function of the AV node is to
add a brief delay between the contraction of
the atria and the contraction of the ventricles.
It also sends a signal to the bundle of His,
located in the interventricular septum
between the ventricles. The bundle of His
carries the signal to the Purkinje fibers,
which contract the ventricles.
Systole
- occurs right after the ventricles eject their
blood into the arteries they connect to. Therefore, it is the phase of the cardiac cycle where blood pressure is highest in the arteries. The aorta is the blood vessel that experiences the highest blood pressure. - Systole happens between the lub-dub sounds.
Diastole
- occurs right after the atria contract to fill
the ventricles. The myocardium is completely
relaxed at this point. Diastole is the phase of the cardiac cycle where blood pressure is lowest in the arteries. - Diastole occurs between the dub and next lub
sound.
Lub-systole-dub-dystole-lub
heart “lub-dub” sound
- Lub – The atria are relaxed, while the
ventricles are contracting. The noise
comes from the AV valves snapping shut
as the ventricles contract. - Dub – The atria are contracting, while the
ventricles are relaxing. The noise comes
from the semilunar valves snapping
shut.
Signal Transduction
- The heart has intercalated discs that connect
adjacent heart cells (cardiomyocytes). Intercalated discs are made of desmosomes and gap junctions and function to transmit the signal to contract in a coordinated, rhythmic fashion.
Measuring Cardiac Cycle
P wave – atrial depolarization
Q wave – depolarization through interventricular septum
R wave – ventricular depolarization
S wave – completion of ventricular depolarization
T wave – ventricular repolarization
Heart rate (HR)
- is how fast the heart beats. Tachycardia is greater than 100 beats per minute, bradycardia is less than 60 beats per minute.
Stroke volume (SV)
- is the volume of blood pumped from the heart with each beat. Stroke volume is calculated by subtracting end-systolic
volume from end-diastolic volume.
Cardiac output (CO)
- is the stroke volume multiplied by the heart rate. This tells us the volume of blood being pumped by the heart in 1 minute.
CO = HR x SV
Total peripheral resistance (TPR)
- is the total amount of resistance that blood faces when flowing through the vasculature of the body. Vasoconstriction increases TPR, while vasodilation decreases TPR.
Systolic blood pressure
- is the highest pressure in your arteries when your ventricles contract. This is the top number in a blood pressure reading. 120/80 → 120 mmHg is the systolic pressure.
Diastolic blood pressure
- is the pressure in your arteries while the heart is relaxing between beats. This is the bottom number in a blood pressure reading. 120/80 → 80 mmHg is the diastolic pressure.
Mean arterial pressure (MAP)
- is the average arterial pressure during one complete cardiac cycle. It is calculated by multiplying your cardiac output by your total peripheral resistance.
MAP = CO x TPR
MAP = (HR x SV) x TP
Vessels transport blood to and from the heart in a closed circulatory system. _____ move blood away from the heart, while _____ move blood toward the heart.
1) Arteries
2) Veins
______ are where blood pressure is the highest due to the ______ from the heart. They branch off into smaller arteries called ______. This is where we see the greatest ______ of blood pressure. Arterioles branch further into ______, which are vessels that are 1 cell thick and diffuse gas and nutrients to the ______. (Even though arterioles see the greatest drop in BP, they are not where BP is lowest. BP is lowest in the ______)
1) Arteries
2) hydrostatic power
3) arterioles
4) drop
5) capillaries
6) interstitial fluid
7) veins
_______ also collect waste and CO2 and enter a _______, which then connects to a vein, which brings the blood _______ to the heart. Blood moves back to the heart by a series of valves within the veins that _______ of blood. _______ are a type of valve in veins. _______ squeeze the veins to push the blood _______, it is not the pumping of the heart that moves blood through the veins.
1) Capillaries
2) venule
3) back
4) prevents backflow
5) Pocket valves
6) skeletal muscles
7) forward
Veins contain _____ blood by volume than arteries and have the _____ blood pressure of all vessels.
1) more
2) lowest
_______is a mechanism that protects our blood vessels from damage. When a tear in our blood vessels occurs, the blood clotting cascade then ‘plugs’ the tear, sealing any vessel leaks.
1) Blood clotting
The blood clotting cascade is an example of a
_________. Damaged tissues release a signal that attracts _________ to the site → each platelet will then release a signal to attract more platelets → a clot is formed.
1) positive feedback mechanism
2) platelets
Blood Clotting Process
- Tissue damage – Damaged tissue tears
blood vessel walls, exposing their collagen. - Platelet activation – Exposed collagen
triggers platelet activation. Platelets will
adhere and aggregate at the site of the
tear, forming a platelet plug. - Thromboplastin release – Activated
platelets release the tissue factor
thromboplastin that converts
prothrombin (inactive precursor) →
thrombin (active form). - Formation of clot – Activated thrombin
converts fibrinogen (inactive precursor) →
fibrin (active form). Fibrin strands
polymerize with other fibrin strands, and
attach platelets to form a blood clot
(hemostatic plug).
Components of Blood
1) Plasma
2) WBC (leukocytes)
3) Platelets (Thrombocytes)
4) RBC (erythrocytes)
Plasma
-contains water, proteins, nutrients,
hormones, and makes up most of the blood
volume. Makes up ~55% of blood volume.
White blood cells (leukocytes)
- are our immune cells and defend against infection. The most common white blood cell is the neutrophil.
Platelets (thrombocytes)
-are cytoplasmic cell fragments that do not have a nucleus, they are responsible for clotting. Large bone marrow cells called megakaryocytes are the precursor to platelets. Platelets release factors that help convert fibrinogen into fibrin, which creates a ‘net’ to stop bleeding. Many of the clotting factors are synthesized with Vitamin K, a deficiency in Vitamin K will lead to increased bleeding. Platelets are also immune cells that function in the innate immunity. Leukocytes and thrombocytes make up <1% of blood volume.
Large bone marrow cells called ______ are the precursor to platelets. Platelets release factors that help convert ______ into ______ , which creates a ‘net’ to stop bleeding. Many of the clotting factors are synthesized with ______ , a deficiency in ______ will lead to increased bleeding. Platelets are also immune cells that function in the innate immunity. Leukocytes and thrombocytes make up ______ of blood volume.
1) megakaryocytes
2) fibronogen
3) fibrin
4) Vitamin K
5) vitamin K
6) <1%
Red blood cells (erythrocytes)
- are responsible for transporting oxygen attached to hemoglobin. Mature red blood cells are anucleate (they don’t have a nucleus) in order to maximize the amount of space they have to carry hemoglobin and oxygen, making them very flexible. Makes up ~45% of blood volume.
Blood types
- Red blood cells (erythrocytes) have antigens on their surfaces. These antigens are little sugars and proteins that mark our blood as a certain type. Blood types are described as follows.
● Type A blood - has ‘A’ antigen
● Type B blood - has ‘B’ antigen
● Type AB blood - has both ‘A’ and ‘B’ antigen
● Type O blood - has neither ‘A’ or ‘B’
antigens
If a person receives a blood transfusion with the incorrect blood type, their immune system will cause the _____ (clumping together) of antibodies of that blood type.
1) agglutination
In addition to blood type A and B, your body also has another surface protein called the _____ . You either have the factor _____ or you do not _____ . If a donor is Rh(+) , they _____ donate to someone who is Rh(-), because the donor has antigens on the surface of the blood cell.
1) Rhesus factor (Rh)
2) Rh+
3) Rh-
4) cannot
A _____ (blood donor who can donate to anyone) is _____. O blood type has neither A nor B surface antigens, and _____ blood also does not have an Rh surface antigen. This means there are no blood cell surface antigens that would stimulate
immune clearance by someone receiving the O (-) blood.
1) universal donor
2) O-
3) O-
A _____ is _____ . Because an _____ person has both A and B cell surface antigens, as well as an Rh surface antigen, they can receive any blood type and not mount an immune response. Any blood cell surface antigen they receive would be something their blood cells already have.
1) universal acceptor
2) AB+
3) AB+
Fetal Circulation:
A fetus gets the oxygen and nutrients from the
_____ via the _____, which gets its
oxygen from its mother. Because the fetus gets its oxygen through the placenta, the blood in its heart does not need to go to the _____(it is not exposed to air). Instead, oxygenated blood in the _____ goes to the left atrium via the _____ (hole in the heart).
1) placenta
2) umbilical cord
3) pulmonary system
4) right atrium
5) foramen ovale
Fetal circulation
has a few unique structures:
1) Umbilical Vein
2) Ductus Venosus
3) Ductus arteriosus
4) umbilical artery
Umbilical vein
- Carries oxygenated blood
from the placenta to the fetus via the
umbilical cord. This differs to veins within
the rest of the mother, as veins otherwise
carry deoxygenated blood from the tissues.
Ductus venosus
- Connects the umbilical
vein to the inferior vena cava, allowing
oxygenated blood coming from the
umbilical vein to flow into the inferior vena
cava and mix with oxygen-poor blood
(blood is now slightly oxygen rich).
Ductus arteriosus:
- Connects the
pulmonary artery to the aorta, allowing
oxygen-poor blood to leave the pulmonary
artery and enter the descending aorta,
preventing oxygen-poor blood from
traveling to the brain.
Umbilical artery:
- Carries deoxygenated
blood from the fetus to the placenta. This
differs from arteries within the rest of the
mother, as arteries otherwise carry
oxygenated blood to the tissues.
_____ and _____ from the fetus is removed from the _____ to the _____ . There is no mixing of the mother’s and fetus’ blood in the placenta; the _____ provides an exchange of gas and nutrients across a barrier.
1) waste
2) CO2
3) right ventricle
4) ubmilical cord
5) placenta
Erythroblastosis Fetalis:
- If the mother has Rh (-) blood type and the fetus has Rh (+) blood, during labor, the fetal Rh (+) blood will enter the mother’s
system, and she will develop anti-Rh antibodies. This will not pose a problem in the first pregnancy, but if the mother becomes pregnant again with another Rh (+) fetus, the mother’s anti-Rh antibodies will attack the fetus, because antibodies are small enough to cross the placental barrier.
The lymphatic system
- is a subsystem of the circulatory system that regulates fluid levels and produces immune cells. Its components are lymph nodes, lymph vessels, adenoids (lymphatic tissue), the spleen, and the thymus.
Nutrient and gas exchange occur at the level of the _____. _____ pushes fluid out of the capillaries on the arterial end into interstitial space. _____, a type of osmotic pressure, brings fluid back into the capillaries at the venule end. However, not all the fluid is reabsorbed from the interstitial space into the venule. _____ collect the remaining fluid, called _____, which consists of interstitial fluid, bacteria, fats, and proteins.
1) capillaries
2) Hydrostatic Pressure
3) Oncotic pressure
4) lymphatic capillaries
5) lymph
The lymphatic capillaries merge together to form
larger vessels that travel to the heart. Along the
way, the lymph is filtered through ______,
which are centers for the ______ to eliminate infections.
1) lymph nodes
2) immune response system
Lymph vessels have ____ pressure (like veins), but
the constriction of ____, in conjunction
with the ____ present in the lymphatic
vessel walls allows for the propulsion of lymph via
____. This allows fluid to move towards the
heart, and backflow of fluid is prevented with a
system of valves, similar to veins.
1) No
2) skeletal muscles
3) smooth muscles
4) peristalsis
Solute concentration
- influences lymph volume. If
there is an increased amount of proteins (ex.
albumin) within the blood vessels, water will flow
into these vessels, reducing the amount of water
left in the interstitial fluid and decreasing lymph
volume.
Respiration:
-the exchange of gases between the
outside environment and the inside of an
organism.
Cnidaria (respiration)
- are small invertebrates that use
simple diffusion for respiration due to the lack
of a circulatory system. Almost all cells must be
in direct contact with the environment.
Environment must be moist for diffusion to
happen.
Annelida (respiration)
- includes earthworms that also use
simple diffusion for respiration but have a
closed circulatory system. They use a slimy
mucus to facilitate the transport of oxygen
into their closed circulatory system.
Arthropoda (respiration)
- are invertebrates, such as
insects and crustaceans, that have an open
circulatory system with hemolymph, a fluid
similar to blood. Gas exchange happens
mainly through the tracheal system for
insects and through book lungs for
arachnids.
Fish (respiration)
- Fish are a part of the phylum Chordata and
have a closed circulatory system with blood
to transport gas. Fish have gills with a large
surface area for gas exchange and use
countercurrent exchange to efficiently
absorb oxygen and remove carbon dioxide
from their blood.
Lungs
-are located in the thoracic cavity and are
covered by the rib cage. The left lung has two lobes
and is smaller than the right lung, which has three
lobes.
The pleura
- covers the lungs and is a dual-layered
membrane composed of the parietal layer (outer
layer) and the visceral layer (inner layer).
The diaphragm
- is a large skeletal muscle at the
bottom of the lungs and is involved in inspiration
and expiration. This is the only organ that only and
all mammals have.
The pleural space
- is a fluid-filled space in between
the parietal and visceral layers. This space is at a
lower pressure than the atmosphere, and creates
the intrapleural pressure.
Inspiration or inhalation
- involves the
contraction of the diaphragm (pulls lungs
downwards) and the external intercostal
muscles (expands the rib cage). These
contractions cause the pressure of the
intrapleural space to decrease and the volume
of the lungs to increase, bringing air into
the lungs.
Expiration or exhalation
- involves the
relaxation of the diaphragm and the
external intercostal muscles, bringing the
lungs back up and closing up the rib cage
through elastic recoil. This causes the
pressure of the intrapleural space to
increase and the volume of the lungs to
decrease, driving air out of the lungs. The
internal intercostal muscles can also
contract during a more forced expiration,
closing the rib cage even more.
Tidal volume
- is the volume of air that moves
through the lungs between a normal inhalation
and exhalation.
Inspiratory reserve volume
- is the maximum
volume of air that can be inhaled further after a
normal inhalation is already taken in.
Expiratory reserve volume
- is the maximum
volume of air that can be exhaled further after a
normal exhalation is already released.
Residual volume
- is the minimum amount of air
that needs to be present in the lungs to prevent
collapse.
Functional residual capacity
- is the entire volume
of air still present in the lungs after a normal
exhalation. It is also the sum of the expiratory
reserve volume and the residual volume.
FRC=ERV + RV
Vital capacity
- is the maximum amount of air that
can be exhaled after a maximum inhalation. It is
the sum of the inspiratory reserve volume, tidal
volume, and expiratory reserve volume.
Total lung capacity
- is the sum of the vital
capacity and the residual volume: it is the
maximum volume the lungs could possibly hold at
any given time.
Refer to page 78 DAT Bootcamp
The nasal cavity contains ______ (secrete mucus) and ______ (move mucus and trapped debris) that work in tandem with each other.
1) goblet cells
2) ciliated epithelial cells
The pharynx
- is at the beginning of the throat
after the nasal cavity. Under the control of the
epiglottis, it diverts air and food into the
larynx and the esophagus.
The larynx
- receives air and contains the
voice box. The upper respiratory tract
refers to the nasal cavity, pharynx, and
larynx. On the other hand, the esophagus
receives food and connects to the stomach.
The trachea
- is below the larynx and has
reinforced cartilage along with ciliated
epithelial cells to filter air.
Next are the two main ___________,
which branch into smaller ________ and
eventually into alveoli. The lower
respiratory tract refers to the trachea,
bronchi, bronchioles, and ________. Alveoli
contain________ epithelial cells (structural
support) and________ epithelial cells (produce
surfactant). ________ is a substance that
prevents the alveoli from collapsing by
reducing surface tension.
1) left and right bronchi
2) bronchioles
3) alveoli
4) type 1
5) type 2
6) surfacant
Overall Pathway of Air
Nasal Cavity → Pharynx → Larynx → Trachea →
Bronchi → Bronchioles → Alveoli
Differences in ________ allow gases to flow
from areas of ________ pressure to areas of ________
pressure through simple diffusion. This is required
for ________ (gas exchange between
inspired air and lung alveolar capillaries) and
________ (gas exchange between
blood and tissues).
1) partial pressure
2) high
3) low
4) external respiration
5) internal respiration
Oxygen:
Air → Blood → Tissues
Carbon Dioxide:
Tissues → Blood → Air
Erythrocytes (red blood cells)
- contain hemoglobin. Hemoglobin is tetrameric and has
a heme cofactor in each of its four subunits.
Heme cofactors are organic molecules that
contain iron atoms, which bind oxygen. Thus,
each hemoglobin can carry up to four oxygen
molecules.
Oxyhemoglobin
- (HbO2) transports most of the oxygen traveling in the blood.
Cooperativity
- describes the process by which
the binding of one oxygen molecule to
hemoglobin makes it easier for others to bind
due to changes in the shape of the hemoglobin
polypeptide. This also works in reverse, allowing
efficient unloading of oxygen in body tissues.
Carboxyhemoglobin (HbCO)
- is produced when
carbon monoxide outcompetes oxygen for
hemoglobin binding. Carbon monoxide poisoning
occurs as a result, because oxygen can no longer
be transported efficiently.
Carbaminohemoglobin
- (HbCO2 ) is a form of hemoglobin that transports carbon dioxide.
However, carbon dioxide is much more soluble in blood than oxygen, so most of the carbon dioxide is dissolved in blood as bicarbonate
anion (HCO3-).
Reduced hemoglobin
- (H+Hb) is produced by H+ ions binding to hemoglobin, outcompeting
oxygen and lowering oxygen binding affinity (less HbO2). On the other hand, carbon dioxide binding affinity is increased (more HbCO2).
Myoglobin
- is a single peptide with one heme
cofactor. It has a much higher affinity for oxygen
than oxyhemoglobin and is found within cardiac
and skeletal muscle cells to bring oxygen in. Also,
myoglobin has a hyperbolic oxygen dissociation
curve because it does not undergo cooperativity
(hemoglobin’s curve is sigmoidal).
The oxygen dissociation curved to be able
- reveals the relationship between the saturation of hemoglobin
with oxygen in the blood and the partial pressure
of oxygen. Certain conditions will shift this curve
either left or right.
A right-shifted curve (oxygen dissociation curve)
- corresponds to a lowered
affinity for oxygen in hemoglobin. Below are the
main reasons for a right-shifted curve.
Affected by:
1) decrease in pH
2) high partial pressure of Co2
3) 2,3-diphosphoglycerate (2,3-DPG) aka 2,3-bisphosphoglycerate (2,3-BPG):
4)Increased body temperature:
Bootcamp Mnemonic: CADET Increase → Right shifted curve
CADET, face Right!
CADET = Carbon dioxide, Acid,
2,3-Diphosphoglycerate, Exercise and
Temperature.
Decreased pH (right-shift curve)
- a lower pH means there is a higher concentration of protons (H+), which
produces reduced hemoglobin. Reduced hemoglobin (H+Hb) has a lowered affinity for binding oxygen, resulting in less HbO2
High partial pressure of carbon dioxide (right-shift curve)
-more carbon dioxide is converted to bicarbonate anions (HCO3-) and protons (H+), which lower oxygen binding affinity through decreased pH.
2,3-diphosphoglycerate (2,3-DPG) aka
2,3-bisphosphoglycerate (2,3-BPG) (right-shift curve)
- accumulates in cells that undergo anaerobic
respiration as a result of the loss of oxygen.
This compound decreases oxygen binding
affinity so more oxygen is released from
hemoglobin to fuel aerobic respiration.
Increased body temperature (right-shift curve)
-: correlates to
more cellular respiration, which uses up
oxygen and produces more carbon dioxide.
Thus, hemoglobin will need to unload more
oxygen for tissues to use and have decreased
oxygen binding affinity.
A left-shifted curve (oxygen dissociation curve)
- corresponds to an increased
affinity for oxygen in hemoglobin. Below are the
main reasons for a left-shifted curve.
Affected by:
1) increased pH
2) Low partial pressure of carbon dioxide:
3) Fetal hemoglobin:
4) Decreased body temperature:
Increased pH (more basic) (A left-shifted curve)
- fewer protons (H+) to produce reduced hemoglobin (H
+Hb), so more oxyhemoglobin (HbO2) remains.
Low partial pressure of carbon dioxide(A left-shifted curve)
- less carbon dioxide is converted to bicarbonate
anions (HCO3-) and protons (H+), leading to increased oxygen binding affinity through increased pH.
Fetal hemoglobin(A left-shifted curve)
- binds oxygen better than
adult hemoglobin to help give oxygen to the
fetus.
Decreased body temperature(A left-shifted curve)
- less cellular respiration, so hemoglobin isn’t influenced to
unload more oxygen and has an increased
oxygen binding affinity.
Bohr effect
- hemoglobin has decreased oxygen
affinity when carbon dioxide is high. Carbon
dioxide is converted to bicarbonate anions and
protons, which produce reduced hemoglobin
(H+Hb).
Haldane effect
- hemoglobin has increased
carbon dioxide affinity when oxygen is low. As a
result of low oxygen, reduced hemoglobin
(H+Hb) levels are higher and have a greater
affinity for carbon dioxide.
The bicarbonate buffering system
-is the main extracellular buffering system in the body. It maintains our blood pH of 7.4 and can be described by the equation below:
CO2 + H2O ↔ H2CO3 ↔ HCO3- + H+
Carbonic acid (H2CO3)
Bicarbonate anion (HCO3–)
The Bicarbonare buffering system is catalyzed by ______ in
both directions based on concentrations. ______ is an enzyme present in ______.
1) carbonic anhydrase
2)carbonic anhydrase
3) RBC
Carbonic Anhydrase in RBC
- In erythrocytes (red blood cells) in the
systemic circulation, the partial pressure of
carbon dioxide is low. As a result, carbon
dioxide continuously diffuses in from the
tissues, and is converted into bicarbonate
and protons. Bicarbonate is able to diffuse
out of the cell, however, protons (H+) cannot
leave. As some bicarbonate diffuses out, this
creates a positive charge within the
erythrocyte, and chloride ions (Cl-) must
diffuse into the blood cell to cancel out the
positive charge of the protons. This process
is known as the chloride shift. - Influx of protons causes the pH to decrease
within the erythrocyte, resulting in the
conversion of oxyhemoglobin into reduced
hemoglobin. Reduced hemoglobin has lower
affinity for O2, leading to release of oxygen
which diffuses to the tissues.
The phosphate buffering system
- is the main intracellular buffer system in humans that
regulates our body’s intracellular pH.
Gas Exchange in Lungs
- Blood travels to the lungs through bulk flow.
- Since most of the carbon dioxide is present
in the blood plasma as bicarbonate ions
(HCO3-), the bicarbonate ions re-enter
erythrocytes at the lungs and chloride ions
leave through the reverse chloride shift. - The bicarbonate buffer system equation
proceeds in the reverse direction, producing
carbon dioxide and water. The carbon
dioxide exits into the alveoli as gas while
oxygen enters the blood, forming
oxyhemoglobin.
The medulla oblongata
- is located in the brain
and controls the diaphragm to regulate
respiratory rate. Central chemoreceptors and
peripheral chemoreceptors signal to the medulla.
Central chemoreceptors
-are located in the medulla oblongata and contained within the
blood-brain barrier. Since carbonic anhydrase is present in the cerebrospinal fluid, carbon dioxide
is converted into bicarbonate ions and protons here. However, protons cannot exit through the blood-brain barrier. As carbon dioxide accumulates, acidity increases and is directly sensed by central chemoreceptors, which signal
to the medulla oblongata to increase breathing rate.
Peripheral chemoreceptors
- surround the aortic
arch and carotid arteries. These peripheral
chemoreceptors directly sense oxygen, carbon
dioxide, and proton levels to signal to the medulla
oblongata. When carbon dioxide is high and
oxygen is low, peripheral chemoreceptors signal to
the medulla oblongata to increase breathing rate.
Respiratory acidosis
– lowered blood pH occurs
due to inadequate breathing (hypoventilation).
Respiratory alkalosis
- increased blood pH
occurs due to rapid breathing
(hyperventilation).
Metabolic acidosis (lowered blood pH) and
metabolic alkalosis (increased blood pH)
- occur as a result of imbalances in carbon dioxide, oxygen,
or proton levels.
Pathogens:
-harmful microorganisms that cause
disease. Common diseases caused by bacterial
pathogens include gonorrhea, tuberculosis,
leprosy, and syphilis.
Viruses can also be pathogens. Common viral
infections include HIV, AIDS, influenza, measles,
and herpes.
Leukocytes:
- white blood cells.
Lymphocytes:
- white blood cells found mainly in
the lymphatic organs (T cells, B cells, natural killer
cells) that originate from the bone marrow. T cells
mature in the thymus while B cells mature in the
bone marrow.
The innate immune system
- is the first line of defense and generates a nonspecific immune
response (generalized). There are two parts:
1) External Immunity
2) Internal Immunity
External immunity
- physical/physiological barriers preventing
pathogen entry. These barriers include
skin, mucous membranes, and chemical
secretions.
Internal immunity
- internal defenses activated by the innate immune system to
neutralize pathogens that have entered.
The body’s Internal immunity is
composed of inflammatory response,
complement proteins, phagocytic and
natural killer cells.
The ______ are the first layer of innate
immunity:
- outer walls
Includes:
1) skin
2) cilia
3) stomach acid
4) symbiotic bacteria
If these barriers are penetrated, the rest of the
immune system will kick in.
Skin
- consists of a thick epidermis, and
dermis. Also mucous membrane to trap
pathogens and lysozyme to break down
bacterial cell walls. Has sebaceous glands to
secrete oil (sebum) as a barrier. Sebum also
has antimicrobial properties.
Cilia
- hair-like projections in the respiratory
tract that sweep away debris and pathogens.
Stomach acid
- gastric acid that kills microbes
due to low pH.
Symbiotic bacteria
- outcompete pathogenic
bacteria and fungi.
Innate Immunity: Inflammatory Responses.
______ are a type of leukocyte responsible for
the first part of the inflammatory response, known
as ______:
1) Mast Cells
2) rally signalling
Rally Signaling
- Mast cells sit in the tissue in preparation
for injury. - If there is an injury, mast cells will release
histamine, which dilates blood vessels. - This increases blood flow and makes
vessels more permeable to let immune cells
into the tissues.
5 Signs of Inflammation
1) Swelling
2) Loss of function
3) increased heat
4) Pain
5) Redness
Swelling (5 Signs of Inflammation)
- permeable capillaries result in fluids
leaking into tissues.
Loss of function(5 Signs of Inflammation)
- body part with
inflammation becomes less usable.
Increased heat(5 Signs of Inflammation)
- increased blood flow results
in a higher temperature.
Pain(5 Signs of Inflammation)
- throbbing pain caused by swelling,
which puts continuous pressure on nerve
endings.
Redness(5 Signs of Inflammation)
- increased blood flow causes
redness of skin.
A ______ can also occur due to the inflammatory
response; this is controlled by the ______ and
causes a ______ to kill pathogens with
______ temperatures.
1) fever
2) brain
3) systemic response
4) higher
Diapedesis
-is the process by which cells move
from the capillaries to the tissues in order to fight
pathogens.
Chemotaxis
- is the method by which cells move
in response to a chemical signal. Immune cells
use chemotaxis to move to the tissues.
Granulocytes
-are cells in the innate immune
system with specific granules in their cytoplasm.
The four types of granulocytes include:
1) neutrophils,
2) eosinophils,
3) basophils,
4) mast cells.
Never Let Monkeys Eat Bananas
Neutrophils
- phagocytes in innate immunity
that make up over half of all leukocytes.
Neutrophils are the most common type of
leukocyte found in blood and are one of the
first cells to be recruited to a site of
inflammation.
Lymphocytes
- B cells, T cells, and natural
killer cells. B and T cells are part of adaptive
immunity and must be activated. Natural
killer (NK) cells are part of innate immunity
and attack virally-infected cells + cancerous
cells. NK cells use perforin (create holes) and
granzyme (stimulate apoptosis) to lyse cells.
B and T cells are the most common type of
leukocyte found in lymph.
Natural killer (NK) cells
- are part of innate immunity
and attack virally-infected cells + cancerous
cells.
NK cells use ______ (create holes) and
______ (stimulate apoptosis) to lyse cells.
B and T cells are the most common type of
leukocyte found in lymph
1) perforin
2) granzyme
Macrophages/Monocytes
- phagocytes in innate immunity. Monocytes are the
immature form found in blood vessels and
macrophages are the mature form after
diapedesis. Can also act as antigen-presenting
cells to activate adaptive immunity.
Eosinophils
- part of innate immunity and
have granules that can be released to kill
pathogens, especially parasites.
Basophils
- least numerous leukocyte;
contains granules with histamine
(vasodilation) and heparin (an anticoagulant
to prevent blood clotting). Very similar to
mast cells, except basophils circulate as
mature cells while mast cells circulate as
immature cells.
Dendritic cells
- are also part of innate immunity
and scan tissues using pinocytosis (cell drinking)
and phagocytosis (cell eating). They act as
antigen-presenting cells like macrophages,
migrating to the lymph nodes to activate
adaptive immunity.
Macrophages and dendritic cells use ______ to recognize conserved parts of _____. Binding to these receptors triggers
_______ and activates the innate immune
system.
1) toll-like receptors (TLR’s)
2) microbes
3) phagocytosis
Interferons
- are secreted by virally-infected cells
and bind to non-infected cells to prepare them for
a virus attack. Also, interferons help activate
dendritic cells.
Platelets
- are also a type of immune cell involved
in activating the innate immune system. These
anucleate cells regulate macrophages and
dendritic cells.
Innate Immunity: The ___________ is a group of
approximately 30 proteins that aid immune cells
in fighting pathogens. While small, these proteins
turn each other on through the activation of a
________, producing a large effect.
Upon recognizing a pathogen, a chain reaction of
________ is triggered for the proteins to
activate each other.
1) complement system
2) complement cascade
3) protease activity
Complement protein actions include:
● Tags antigens for phagocytosis in a process
called opsonization
● Amplifies inflammatory response Eg. binds to
mast cells for increased histamine release
● Forms a membrane attack complex (MAC),
which pokes holes in pathogens and lyses
them
The adaptive immune system
- is a specific immune response (targets specific antigens).
An antigen
- is an immunogenic foreign molecule
and is the target of the immune response. The
epitope is the important part of the antigen that
is recognized by the immune cell.
The immune system recognizes self proteins from
non-self proteins using the _______, which is
found on the surface of cells. Thus, foreign
antigens and foreign MHC will be identified as
enemies by the immune system.
1) major histocompatibility complex (MHC)
include:
MHC Class 1 MHC Class 2
MHC Class I
- is a surface molecule present on all
nucleated cells, and each genetically different
individual will have a different MHC I molecule.
_______ that have different _______ may
lead to failure and rejection, so
immunosuppressants are given to transplant
patients. Also, _______ occur when
the immune system attacks self MHC I.
1) organ transplants
2) MHC 1
3) autoimmune diseases
MHC Class II
- is a surface molecule present on
antigen-presenting cells (dendritic cells,
macrophages) and is used to present foreign
antigens to activate immune cells.
Identical twins have identical ______molecules. This allows
identical twins to donate organs to each other
without the need for immunosuppression (the
donated organ cells won’t be marked as foreign).
1) MHC
B cells
- control antibody-mediated immunity
(humoral immunity) by managing the
production and release of antibodies. They can
also act as antigen-presenting cells.
B cell receptors (BCRs)
- are located on B cells
and bind to antigen epitopes either free-floating
or on APCs. Each B cell has a unique BCR.
The clonal selection model
- describes the development of one type of BCR for every B cell.
Through clonal expansion, these B cells divide
into either plasma cells (antibody-secreting cells)
or memory B cells (to be activated later in case
of another attack).
Antibodies (immunoglobulins)
- are structurally identical to BCRs but freely circulate in blood and
lymph. They can tag antigens for phagocytosis,
neutralize the antigen by coating it, or activate
the complement system. Antibodies contain light
chains and heavy chains that are linked
together by disulfide bonds. In addition, the
variable region recognizes different antigens
while the constant region is the same for
antibodies within the same class. As
glycoproteins, the five classes of antibodies all
contain a sugar residue that assists in
attachment to other cells.
Antibodies contain_____ and _____ that are linked
together by _____. In addition, the
_____ region recognizes different antigens
while the _____ region is the same for
antibodies within the same class. As
glycoproteins, the five classes of antibodies all
contain a sugar residue that assists in
attachment to other cells.
1) light chain
2) heavy chains
3) disulfide bonds
4) variable
5) constant
The 5 classes of antibodies include:
1) IgM
2) IgA
3) IgE
4) IgD
5) IgG
IgM
– present in a pentameric form and is the
largest antibody. The first antibody to be
produced; activates the complement system.
IgA
- present in a dimeric form and found
most abundantly in bodily secretions.
Newborns receive passive immunity
through breast milk containing IgA. Also, IgA
mainly binds pathogens externally, outside
of circulation.
IgE
- monomer that is present on basophils
and mast cells as antigen receptors. When
bound to an allergen, it triggers histamine
release and an allergic reaction. Think Ig
sneEze.
IgD
- monomer that we have very little
information about. Only small amounts are
produced.
IgG
- monomer that is the most abundant
antibody in circulation. Also the only antibody
that can cross the placenta to give fetus
passive immunity. Helps the complement
system to cause opsonization (tags antigens
and subsequent phagocytosis).
Memory B cells
- survive for a long time and lay
dormant until reactivated by the same antigen
that triggered the original clonal expansion.
They are the key to vaccinations because
vaccines cause memory B cell production for
later reactivation. After reactivation, memory B
cells cause massive antibody production.
T cells
- control cell-mediated immunity by
directly acting on cells instead of sending
antibodies out.
T cell receptors (TCRs)
-are unique just like BCRs,
binding only to one type of antigen per T cell.
Thus, T cells also undergo clonal selection just
like B cells.
T cells must bind to antigens presented on _________to be activated.
- APC (antigen-presenting cells)
There are two ways antigens may be presented to T cells:
1) MHC I presentation
2) MHC II presentation
MHC I Presentation:
- T cells differentiate into
CD8/CD8+ T cells (cytotoxic T cells), which
directly kill infected cells through perforin
(poke holes) and granzymes (cause apoptosis).
However, T cells are different from natural
killer cells because they are more specific and
require antigen presentation.
MHC II Presentation:
- T cells differentiate into
CD4 T cells (helper T cells), which release
interleukins to boost both innate immunity
and adaptive immunity. These interleukins help
attract innate immune cells and increase
proliferation of other T and B cells.
Passive immunity
- refers to the immunity one
organism gains from receiving the antibodies
from another organism that already has that
immunity. For example, a fetus gains passive
immunity through the placenta (IgG) while a
newborn gains passive immunity through breast
milk (IgA). The fetus and newborn are referred
to as immuno-naive because they do not yet
have their own active immunity.
Active immunity
- refers to the immunity an
organism gains from being infected once already
by a pathogen. A vaccination introduces the
antigen or pathogen in a deactivated state to
stimulate active immunity, which is referred to as
artificial immunity in this case and induces
memory B and T cell formation.
The neuron
- is the most basic unit of the nervous
system. It has three parts: the soma (cell body),
dendrites (extensions that receive signals), and
the axon (sends signals out).
The Axon include:
1) Axon hillcock
2) Myelin Sheath
3) Nodes of Ranvier
Axon hillock
- area where the axon is
connected to the cell body. Responsible for the
summation of graded potentials.
Myelin sheath
- fatty insulation of the axon
that speeds up action potential propagation by
stopping ion exchange. The myelin sheath is
formed by oligodendrocytes (in the central
nervous system) and Schwann cells (in the
peripheral nervous system). Thicker
myelinated neurons fire signals faster.
The myelin sheath is
formed by _______ (in the central
nervous system) and ______ (in the
peripheral nervous system). _____
myelinated neurons fire signals faster.
1) oligodendrocytes
2) Schwann Cells
3) thicker
Mnemonic: COPS
Central NS: Oligodendrocytes
Peripheral NS: Schwann cells
Nodes of Ranvier .
- gaps between myelin
sheaths where ion exchange occurs.
Propagation of the action potential occurs
here, jumping from gap to gap (node to node)
in a process called saltatory conduction
Steps of action potential:
- At resting potential, the membrane potential of the neuron is around -70mV and is maintained by Na +/K + ATPases, which pump 3 Na+
ions out and 2 K+ions in, powered by hydrolysis of one ATP. K+ leak channels are also present and help maintain resting
potential through passive K+leakage. - When a stimulus causes threshold potential to be reached (around -55mV in neurons), voltage-gated Na+ channels open up, letting Na+ in, resulting in depolarization of the neuron. K channels are closed.
- Next is repolarization of the neuron due to the opening of voltage-gated K+ channels, letting K+ out, and the closing of Na channels. This causes the membrane potential to become less positive since positive ions are
leaving. This is the absolute refractory period- no stimulus can cause an action potential. - When the membrane potential becomes even more negative than the normal resting potential, this is known as hyperpolarization. This results in a relative refractory period being established, during which another action
potential can be fired, but it requires a much stronger stimulus. - The membrane potential returns to normal resting potential through the pumping of Na+/K+ ATPases and K+ leak channels.
At resting potential, the membrane potential of the neuron is around ______ and is maintained by ______, which pump ______ Na+
ions out and ______ K+ ions in, powered by hydrolysis of one ATP. ______ are also present and help maintain resting
potential through passive K+leakage.
1) -70mV
2) Na+/K+ ATPase
3) 3
4) 2
5) K+ leak channels
When a stimulus causes threshold potential to be reached (around _____ in neurons), _____ open up, letting Na+ in, resulting in depolarization of the neuron. K channels are _____.
1) -55mV
2) voltage-gated Na+ channels
3) closed
_____ of the neuron occurs due to the _____ of voltage-gated K+ channels, letting K+ out, and the closing of Na channels. This causes the membrane potential to become _____ positive since positive ions are
leaving. This is the _____ - no stimulus can cause an action potential.
1) repolarization
2) opening
3) less
4) absolute refractory period
When the membrane potential becomes even more _____ than the normal resting potential, this is known as _____. This results in a _____ being established, during which another action potential can be fired, but it requires a much _____ stimulus.
1) negative
2) hyperpolarizatoin
3) relative refractory period
4) stronger
The absolute refractory period
-refers to the period after the initiation of the action potential
during which another action potential cannot be
fired no matter how powerful the stimulus is. It is
due to the inactivation of voltage-gated Na+
channels after they open.
The relative refractory period
- refers to the period after the action potential fires during which
a stronger than normal stimulus could cause
another action potential to be fired.
The synapse
- is the space between two
neurons.
The ______ neuron sends the
signal and releases ______ into the
synapse, while the postsynaptic neuron
receives the signal by interacting with the
released _______.
1) presynaptic
2) NT (neurotransmitters)
3) NT (neurotransmitters)
Steps of synaptic transmission:
- Action potential reaches the end of the
presynaptic axon, causing voltage gated
calcium channels to open and letting Ca2+
ions into the neuron. - The Ca2+ ions cause synaptic vesicles to fuse
and undergo exocytosis, releasing
neurotransmitters into the synapse. - The neurotransmitters (described in the table
on the next page) bind to ligand-gated ion
channels on the postsynaptic neuron,
producing graded potentials (depolarizations
or hyperpolarizations of the membrane). - These graded potentials summate at the axon
hillock and an action potential will fire if the
summation of graded potentials is higher than
the threshold potential of neurons.
An excitatory postsynaptic potential (EPSP)
- is a graded potential that depolarizes the membrane.
In an EPSP, excitatory neurotransmitters cause Na+
ion gates to open and let Na+ ions flow into the cell.
An inhibitory postsynaptic potential (IPSP)
- is a graded potential that hyperpolarizes the
membrane. Inhibitory neurotransmitters cause K+
ion gates to open and let K+ ions flow out of the
cell. Another IPSP type allows influx of Cl-,
allowing negative Cl- ions in.
Glial cells
- are non-neuronal cells in the nervous
system that help support and surround neurons.
They are divided into microglial cells and
macroglial cells.
Microglial cells
- are macrophages that protect the
central nervous system (CNS).
Macroglial cells have many subtypes:
1) astrocytes
2) schwann cells
3) oligodendrocytes
4) satellite cells
5) ependymal cells
Astrocytes
- are the most abundant glial cell
and form the blood-brain barrier. They also
help recycle neurotransmitters and provide
blood supply to the CNS neurons.
Schwann cells
- form the myelin sheath in the
peripheral nervous system (PNS).
Oligodendrocytes
- form the myelin sheath in
the central nervous system (CNS).
Satellite cells
- have the same functions as
astrocytes but instead help PNS neurons.
Ependymal cells
- produce cerebrospinal fluid
(CSF), which cushions the CNS.
Different NT:
Amino Acids:
Glutamate
Gamma-aminobutyric acid(GABA)
Glycine
Amino acid derived:
Epinephrine
Norepinephrine
Dopamine
Serotonin
Neuropeptides:
Short chain amino acids (e.g.: substance P)
Gasotransmitters:
Nitric Oxide
Other:
Acetylcholine
Glutamate
- main excitory NT of CNS; most abundant of vertebrate NS; NT of neuromuscular junction in invertebrates
GABA
- inhibitory NT of the brain
Glycine
- inhibitory NT of CNS (spinal cord, brainstem, and retina)
Epinephrine
- excitatory postsynaptic NT of sympath. NS
Norepinephrine
- excitatory postsynaptic NT of sympath. NS
Dopamine
- excitatory postsynaptic NT of the brain; involved in reward-motivated behaviour
Serotonin
-inhibitory postsynaptic NT of the brain; involved in mood, appetite, sleep, and learning;
- increases contraction of gastrointestinal tract in response to food intake
Short chain a.a. (substance P)
- diverse roles; wide range of brain functions
Nitric Oxide
- smooth muscle relaxation; in blood vessels, it causes vasodilation which leads to decrease in BP
- unlike other NT, NO is synthesized and released on demand rather than stored in vesicles
ACh
- excitatory NT of NJ (neuromuscular junction) in vertebrates
- pre-synaptic NT of SNS/PNS
- post-synaptic NT of PNS
The central nervous system (CNS)
- is composed of the brain and spinal cord.
The peripheral nervous system (PNS)
- is composed of nerves branching off the CNS.
During embryonic development, the brain can be
divided into three areas:
1) The forebrain develops into:
a) Telecephalon ===> cerebrum
b) Diencephalon ====> thalamus, hypothalamus, and pineal gland
2) The Midbrain develops into:
a) Mesencephalon ====> midbrain
3) The Hindbrain develops into:
a) Metencephalon ===> pons, cerebellum
b) Mylencephalon ===> medulla oblongata
The developed brain cortex is divided into four
main lobes:
1) Frontal lobe
2) temporal lobe
3) occipital lobe
4) parietal lobe
Frontal lobe
- known for higher function processes such as decision making,
problem solving, attention and concentration.
Temporal lobe
- known for speech and hearing.
Occipital lobe
– known for vision.
Parietal lobe
- is known for spatial perception and sensation.
The cerebellum
- is located underneath the
occipital lobe and is responsible for the
coordination of movement.
The brainstem is composed of the following
components:
1) Midbrain
2) Pons
3) Medulla Oblongata
4) Reticular Formations
Midbrain
- relays senses to other parts of
brain
Pons
-relays messages between the
forebrain, cerebellum, and medulla
Medulla oblongata
- heart and breathing
rate, blood pressure, toxin sensing.
Connects the cerebrum/cerebellum to the
spinal cord.
Reticular formations
-are neurons throughout the brainstem that are
involved in cortical arousal, and
consciousness.
The limbic system
- is composed of the thalamus,
hypothalamus, hippocampus, and amygdala. It
is responsible for emotion, memory, learning, and
motivation.
Thalamus
- The “relay center” of the brain
and is located between the cerebrum and
the midbrain. Relays sensory and motor
signals from the body to the brain.
Hypothalamus
- Regulates hormone secretion in the body.
Hippocampus
- Responsible for memory
consolidation.
Amygdala
- Responsible for the emotional
reaction to certain scents.
The _________ is nervous tissue in part of the central nervous system; it connects the brain to the body. ______ send signals to the spinal cord and subsequently the brain through dorsal roots. ______send signals back out to the muscles through ______.
1) spinal cord
2) Sensory (afferent) neurons
3) Motor (efferent)
neurons
4) ventral roots
The meninges
1) protect the CNS and have three
layers called the dura mater, arachnoid, and pia
mater.
The ______ is divided into the ______ (voluntary motor
action and sensory input) and the ______ (involuntary).
1) PNS
2) Somatic NS
3) autonomic NS
Different types of sensory (afferent) neurons in
the ______ are responsible for
receiving input from stimuli, including
______ (mechanical stimuli),
______ (pain stimuli), ______
(temperature-related stimuli), ______
(chemical stimuli), and ______
(light, electricity, and magnetic stimuli).
1) peripheral nervous system
2) mechanoreceptors
3) nociceptors
4) thermoreceptors
5) chemoreceptors
6) electromagnetic receptors
The ______ can be further divided into the ______
(fight or flight) and the ______ (rest and digest).
1) autonomic NS
2) SNS
3) PNS
Sympathetic nervous system effects:
● Release of sugar into blood for energy.
● Increase in heart rate for oxygen delivery to
the brain and muscles.
● Vasodilation of skeletal blood vessels, and
vasoconstriction of the digestive system.
● Dilation of bronchi and bronchioles to allow
more oxygen into lungs.
● Dilation of the pupil to give the brain more
visual information.
Parasympathetic nervous system effects
(through vagus nerve):
● Relaxation of muscles.
● Decrease in heart rate.
● Maintenance of homeostasis.
● Increase in gastrointestinal activity.
A ganglion
- is defined as a cluster of nerve bodies
in the peripheral nervous system. The autonomic
nervous system’s neurons are either
preganglionic or postganglionic. The
preganglionic neuron comes from the central
nervous system and synapses with the
postganglionic neuron at the ganglion.
Sympathetic nervous system (neuron structure)
→ short preganglionic nerves and long postganglionic
nerves (ganglia far from effector organs)
Parasympathetic nervous system (neuron structure)
→ long preganglionic nerves and short postganglionic
nerves (ganglia close to effector organs)
_______ → uses _______ for preganglionic nerves and
_______ for postganglionic nerves. The sympathetic nervous
system also can stimulate the _______ to
release _______ into the blood.
1) SNS
2) Ach
3) NE/E
4) adrenal medulla
5) NE/E
Parasympathetic nervous system → uses
_______ for both preganglionic and
postganglionic nerves.
1) Ach
Acetylcholinesterase
-is an enzyme that is
responsible for the breakdown of acetylcholine via
hydrolysis.
the Ear is made of:
1) Outer Ear
2) tympanic membrane
3) middle ear
4) stapes
5) cochlea
6) round window
7) semicircular canal
The outer ear
- takes in sound waves, and the
tympanic membrane transfers the sound
from outer ear to middle ear.
The middle ear
- is composed of three bony
ossicles → the malleus, incus, & stapes. The
ossicles transfer vibrations through the middle
ear and amplify the signal.
The stapes
-transfers the vibrations from the
middle to the inner ear via the oval window.
The cochlea
-uses fluid and hairs to convert the
mechanical signal into a neuronal signal,
known as transduction.
The round window
- is a membrane covered
opening between the middle ear and the inner
ear, similar to the oval window. It helps the
fluid expand and vibrate.
The semicircular canal
-has fluid and hairs just
like the cochlea but gives information about
the person’s movement. It is also the reason
we get dizzy.
Different parts of the Eye:
1) Cornea
2) Iris
3) Pupil
4) Lens
5) Retina
6) Fovea
7) Amacrine and bipolar cells
8) optic nerve
9) optic disk
10) sclera
11) choroid
Cornea
- transparent; focuses light and
protects the eye.
Iris
- controls the size of the pupil.
Pupil
- controls how much light enters the eye.
Lens
- focuses images on retina.
Retina
- back of the eye that has
photoreceptors (rods + cones).
Rods
-function at low levels of light
and are responsible for low-light
perception.
Cones
- function at high levels of
light and are responsible for color
perception.
Fovea
- highest concentration of
photoreceptors in the retina and responsible
for high acuity vision.
Amacrine and bipolar cells
- take information
from rods and cones, transmitting the
information to ganglion cells of the optic
nerve fibers.
Optic nerve
- bundle of axons that transmits
visual information to the brain.
Optic disk
- the blind spot of the eye, where
the optic nerve passes through to reach the
brain.
Sclera
- protective connective tissue that
surrounds the eye, the “white part” of the eye.
Choroid
- vascular connective tissue.
Tongue - 5 taste receptors
1) salty
2) sweet
3) bitter
4) sour
5) unamy
Taste information is sent to the ______ and
subsequently the ______.
1) thalamus
2) gustatory cortex
Nose: Contains ______ that sense molecules and send signals to the ______ , which gives us the perception of smell. These signals also integrate in the thalamus and ______ for smell sensation.
1) olfactory receptor cells
2) olfactory cortex
3) orbitofrontal cortex
Smell, also known as olfaction, is the general term for sensing odor molecules, whereas smell perception is the ability to experience a smell. While this distinction may sound minimal, it plays an important role in distinguishing different lines of research
There are three types of muscles
1) smooth muscle
2) cardiac muscle
3) skeletal muscle.
Smooth Muscles
- Present in organs, airways blood vessels
- involuntary
- 1 nucleus per cell
- Not striated
Cardiac Muscles
- Present in heart
- Involuntary
- 1 nucleus per cell
- striated
Skeletal Muscle
- present around bone
- voluntary
- many nuclei per cell
- striated
Striated muscles
- means the muscle contains sarcomeres.
Smooth muscle therefore lacks sarcomeres,
whereas cardiac and skeletal muscle contain them.
Cardiac muscle contains _______,
which are made of _______ (hold cells
together) and _______ that connect the
cytoplasm of cells together to allow _______
and _______.
1) intercalated discs
2) desmosomes
3) gap junctions
4) ion exchange
5) electrical impulse propagation
______ is composed of many bundles
within bundles.
1) skeletal muscles
Muscle → Muscle fascicles → Muscle fibers
(muscle cells) → Myofibrils (contractile protein)
The _______ is the muscle fiber’s cellular
membrane, and it protects each muscle fiber.
1) sarcolemma
The _____ is the cytoplasm of the muscle
fiber and holds the ______.
1) sarcoplasm
2) myofibrils
Muscle structures are lined with protective sheaths
of connective tissue that wrap around the
structure, holding it in the right place. These
sheaths are as follows (from most super):
1) Epimysium
2) Perimysium
3) Endomysium
Epimysium
- The most superficial sheath.
Covers the muscle itself.
Perimysium
- Covers the muscle fascicles.
Endomysium
- The deepest sheath. Covers the muscle fibers.
Sliding Filament Theory of Muscle Contraction:
All muscles always ______ (pull) across a joint
to move body parts, they never push.
1) contract
Sarcomeres inside of myofibrils
- are the functional unit of muscle fibers and shorten to cause muscle
contraction.
Myofilaments
-are contained within sarcomeres,
divided into thin actin filaments and thick
myosin filaments. These filaments slide past
each other to shorten sarcomeres through the
sliding filament model of muscle contraction.
Stimulation of a muscle contraction:
- Action potential propagation reaches the end
of a motor neuron’s axon. - Acetylcholine is released as a
neurotransmitter between the presynaptic
motor neuron and postsynaptic skeletal muscle
fiber at the neuromuscular junction. - Acetylcholine binds to ligand - gated
sodium channels, causing sodium to enter
the cell, which creates graded potentials
on the muscle fibers. - The graded potentials trigger opening of
voltage-gated sodium channels, which may
produce action potentials on the muscle if the
stimulus is large enough.
The ______ is the cell membrane of ______ and contains ______ , invaginations that quicken action potential propagation on the
muscle.
1) sarcolemma
2) striated muscles
3) T-tubules
The ______ is the endoplasmic reticulum of muscle fibers that
______ into the sarcoplasm through voltage-gated calcium
channels when triggered by the ______ of the muscle cell.
1) sarcoplasmic reticulum
2) releases stored calcium ions
3) depolarization
The ______ then bind to ______, which removes ______ from the
myosin-binding-sites on actin, allowing myosin to interact with actin and cause sarcomere shortening, via ______.
1) Calcium ions
2) troponin
3) tropomyosin
4) sliding filaments
Steps of Cross bridge cycling:
- Initiation: Calcium ions expose the
myosin-binding-sites on actin. - A cocked back, high energy myosin head
(containing ADP and Pi) forms a cross bridge
with the actin. - The myosin head contracts and the power
stroke occurs, bringing the myosin head back
to a low energy state and releasing ADP and
Pi (inorganic phosphate). As a result, the sarcomere shortens. - A new ATP molecule binds to myosin, causing
detachment of the myosin head from the
actin filament. - The myosin head is an ATPase, and it
hydrolyzes the ATP into ADP and Pi. This
causes the myosin head to re-enter a cocked
back, high energy state. (Return to Step 2 if
calcium ions present). - Termination: Neuronal signaling from motor
neurons ends. The sarcoplasmic reticulum
pumps calcium back into itself, and troponin
brings tropomyosin back to cover
myosin-binding sites on actin.
______ occurs in dead animals when there is
no ATP available to release myosin from the actin.
1) Rigor Mortis
The Sarcomere includes:
1) Z lines
2) M lines
3) I band
4) A band
5) H zone
Refer to page 96 DAT Bootcamp for image
The Z lines
-are the ends of the sarcomeres. Thin
actin filaments branch from the Z lines towards
the middle of the sarcomere.
The M lines
- are the midpoints of the sarcomeres.
Thick myosin filaments branch from the M lines
towards the ends of the sarcomere.
The I band
- is the area in the sarcomere where
only actin filaments are present. (Mnemonic: “I” is
a thin letter, representing thin actin filaments)
The A band
- is the area in the sarcomere where
actin and myosin overlap.
The H zone
- is the area in the sarcomere where
only myosin is present. (Mnemonic: “H” is a thick
letter, representing thick myosin filaments)
Motor units
- make up muscles; a motor unit refers
to all the muscle fibers innervated by a single
neuron.
Small motor units
- include only a few muscle
fibers and are used in precision movement.
Large motor units
- include many muscle fibers
that are innervated by a single neuron and are
used in powerful movements.
There are three types of muscle fibers that exist:
- Slow oxidative fibers (type I fibers)
- Fast oxidative-glycolytic fibers (type II-a fibers)
- Fast glycolytic fibers (type II-b fibers)
Slow oxidative fibers (type I fibers)
- dark red
- aerobic
- small in diameter
- weak contraction strength
- efficient and fatigue resistant
Fast oxidative-glycolytic fibers (type II-a fibers)
- Dark red
- aerobic/anaerobic
- intermediate in diameter
- strong contraction strength
- intermediate efficiency and fatigue resistance
Fast glycolytic fibers (type II-b fibers)
- white
- anaerobic
- large in diameter
- strongest contraction strength
- somewhat inefficient and fatigue quickly
A twitch contraction
- is the contraction of a muscle fiber through motor unit stimulation. Each
twitch has the same size and duration. Twitch contractions also follow the all-or-none principle, which states that a depolarization will cause all the
muscle fibers to twitch if it is above threshold potential but will not cause any twitching if the depolarization is below threshold potential.
Each twitch has the same _____
- same size and duration
Twitch contractions also follow the ___________, which states that a depolarization will cause all the muscle fibers to twitch if it is above threshold potential but will not cause any twitching if the depolarization is below threshold potential.
1) all-or-none principle
Three phases of a twitch:
1) Latent
2) Contraction
3) Relaxation
Latent (twitch phase)
- action potential spreads over
sarcolemma and T-tubules, signaling to
sarcoplasmic reticulum to release calcium.
Contraction (twitch phase)
- formation of cross bridges as a
result of calcium ions binding to troponin. H
zones shrink and muscle tension increases.
Relaxation (twitch phase)
- calcium is pumped back into the
sarcoplasmic reticulum, ending cross bridge
cycling and decreasing muscle tension.
Summation
- is the process by which twitches add
up to create a larger overall contraction.
2 types:
1) Wave summation (temporal summation)
2) motor unit summation
Wave summation (temporal summation)
- depolarizing a motor unit again during the
relaxation phase. May cause tetanus, which
is when the muscle fibers cannot be further
stimulated due to a lack of relaxation.
Twitches blend together during tetany,
eventually causing fatigue (loss of muscle
contraction).
Motor unit summation
- different motor units are stimulated at different times to
produce the intended amount of muscle
contraction. This is also known as the size
principle of motor unit recruitment
because smaller motor units are stimulated
first before larger motor units come in to
help.
Weak and _____ twitches in small motor unit groups contribute to maintaining _____ (muscle tonus). _____ is never reached because different motor units are stimulated at different times.
1) involuntary
2) muscle tone
3) fatigue
An _____ is an external skeleton. Many
_____ and all _____ possess
exoskeletons.
1) exoskeleton
2) invertebrates
3) arthropods
_____ contain an endoskeleton on the _____. An endoskeleton can be divided into the _____ (core bones) and the______ (appendages).
1) Vertebrates
2) inside
3) axial skeleton
4) appendicular skeleton
Types of bones in the endoskeleton
1) Long Bones
2) short bones
3) Flat bones
4) Sesamoid Bones
5) Irregular Bones
Long bones
- made of cortical bone
(compact) and pockets of cancellous bone
(spongy). Important features include the
epiphysis, diaphysis, medullary cavity,
metaphysis, and epiphyseal plate.
Epiphysis
- end of a long bone that forms
joints with other bones and contains red
bone marrow for hematopoiesis (blood
cell synthesis).
Diaphysis
- long hollow shaft in center of
bone.
Medullary cavity
- located within the diaphysis and contains red and yellow
bone marrow (area of fat storage).
Metaphysis
- similar to epiphyses and
found between the medullary cavity and
epiphyseal plates.
Epiphyseal plate
- “growth plate” located
between epiphysis and metaphysis. Made
out of hyaline cartilage and works to
lengthen the diaphysis through growth and
ossification.
Short bones
- as wide as they are long and
mainly provide support (eg. parts of the
wrist).
Flat bones
- mainly provide protection (eg.
skull).
Sesamoid bones
- found within tendons to
help muscles pull (eg. kneecap).
Irregular bones
- irregularly shaped (eg. pelvis).
Cortical bone
- is the dense outer layer of bone that
supports the weight of our bodies. It is composed
of many microstructures:
1) osteons
2) haversian canals
3) lamellae
4) lacunae
5) canaliculi
6) volkmann’s canals
Osteons
- cortical bone’s functional unit,
composed of tiny multi-layered cylinders.
Also known as haversian systems because
they contain a haversian canal in their center.
Haversian canals
- ‘tubes’ that contain blood
vessels for nutrient supply.
Lamellae
- layers of the osteon.
Lacunae
- small spaces between lamellae that
hold bone cells and interconnect through
canaliculi.
Canaliculi
- small channels that connect
lacunae and the haversian canal.
Volkmann’s canals
- connect Haversian canals
to the periosteum, which provides nutrients.
Cancellous bone
- is the spongy inner layer of bone
that soaks up red bone marrow via a web of
trabeculae (connective tissue that supports
cancellous bone).
Bone remodeling
- is the process of going back and
forth between the processes of ossification (bone
formation) and resorption (bone loss).
Types of cells involved in bone remodeling:
1) osteoprogenitors
2) osteoblasts
3) osteocytes
4) osteoclasts
Osteoprogenitors
- immature precursor cells
that differentiate into osteoblasts.
Osteoblasts
- build bone by secreting
proteins and utilizing blood calcium. They
mature into osteocytes after getting trapped
inside the bone matrix they create.
Osteocytes
- live in lacunae in osteons to
maintain bone.
Osteoclasts
- eat and resorb bone, releasing
calcium and phosphate back into the blood.
Derived from monocytes.
Mechanisms involved in bone remodeling:
1) Parathyroid hormone
2) Vit D
3) Calcitonin
Parathyroid hormone
- increases blood
calcium levels by stimulating osteoclasts and
depressing osteoblasts. Secreted by the
parathyroid gland.
Vitamin D
- increases blood calcium levels by
raising intestinal calcium absorption. Activated
by parathyroid hormone, but provides
negative feedback on PTH production.
Calcitonin
- decreases blood calcium levels by
depressing osteoclasts, allowing osteoblasts to
build bone without competition. Secreted by
parafollicular cells (C cells) of the thyroid
gland.
Mnemonic: CalciTONin = “Tone it down”
Osteoid
- is the organic component of bone
containing many proteins such as collagen (gives
bone tensile strength).
Hydroxyapatite
- is the inorganic mineral
component of bone that gives the bone density
Two types of embryonic ossification:
1) intramembranous ossification
2) endochondral ossification
Intramembranous ossification
- bone is created directly within fibrous membranes,
mainly for flat bones. Osteoblasts start by
secreting osteoid, which hardens and houses
osteocytes. Eventually, cortical bone is
created.
Endochondral ossification
- bone is created
indirectly through a cartilage model, mainly
for long bones. The cartilage model calcifies
during fetal development, creating
ossification centers that help form the
features of long bones.
Types of Connective Tissues:
1) Fibrous connective tissues
2) cartilage
3) joints
Fibrous connective tissue
- has a matrix made up of fibers.
includes:
- tendons
- ligaments
- periosteum
- endosteum
Tendons
- connect muscle to bone.
Ligaments
- connect bone to bone.
Periosteum
- membrane that covers
cortical bone with an outer fibrous layer
(vascularized) and an inner/cambium
layer (collagen for attachment to cortical
bone)
Endosteum
- membrane located between
cortical and cancellous bone.
Cartilage
- is avascular (lacks blood vessels)
and is not innervated (as opposed to bone
which is highly vascular and innervated).
Chondroblasts
-build cartilage by secreting
collagen and elastin.
Includes:
1) Hyaline cartilage
2) fibrous cartilage
3) elastic cartilage
Hyaline cartilage
- slightly flexible and
important in providing support and
stability to joints.
Fibrous cartilage
- high rigidity and resists
tension, found in intervertebral discs and
knee meniscus.
Elastic cartilage
- highly flexible and found
in ears and epiglottis.
Joints
- are vascularized and innervated. They
are found between bones. Below are types of
joints:
1) Synarthroses
2) amphiarthroses
3) diathroses
Synarthroses
- dense, fibrous joints that do
not move.
Amphiarthroses
- cartilaginous joints that
partially move.
Diarthroses
- synovial joints that fully
move. Typically contain hyaline cartilage.
Hormones can be secreted via:
1) Endocrine
2) paracrine
3) autocrine
Endocrine
- through the bloodstream.
Paracrine
- to neighboring cells.
Autocrine
- onto the same cell that is secreting
the hormone.
There are three types of hormones:
1) peptide hormones (protein hormones)
2) Steroid Hormones
3) amino acid derived hormones
Peptide Hormones are made/synthesized from:
- produced in the rough ER and made
of amino acids connected by peptide bonds.
Peptide Hormones act by:
- binds to cell surface receptors because
they cannot pass freely through the cell
membrane as a result of being water-soluble
(and not lipid-soluble). The process of hormone
function is an indirect stimulation. The two
ways the signal can be received is through
intracellular secondary messengers or
ligand-gated ion channels.
Common secondary messengers include:
● cAMP (cyclic AMP)
● IP3 (inositol triphosphate)
● DAG (diacylglycerol)
● Calcium ions (Ca
2+)
One important pathway that uses secondary
messengers is the _____ pathway. Here, IP3
binds to _____ on the _____, triggering the activation and opening
of these calcium channels, releasing calcium
ions into the cytosol.
1) IP3/DAG
2) calcium channels
3) ER
_____ are cell surface receptors that can initiate a _____ response after binding to a peptide hormone extracellularly. A _____ is coupled
to the receptor and dissociates into subunits
(alpha (α), beta (β) and gamma (γ)) after
activation. These subunits then act upon
intracellular second messengers to propagate
the signal.
1) G protein coupled receptors (GPCRs)
2) secondary messenger
3) G protein
_____ are another cell surface receptor that dimerizes and initiates
second messenger responses upon binding to a _____.
The intracellular domains of RTKs cross-phosphorylate each other and initiate second messenger signaling within the cell.
1) Receptor tyrosine kinases (RTKs)
2) Peptide Hormone (e.g.: Epidermal Growth Factor)
The __________ of peptide
hormone signaling allows for quick and
immediate physiological changes.
1) second messenger system
Ligand-gated ion channels
- change shape upon binding to peptide hormones, allowing ions to flow
across the cell membrane. No second messengers
are involved.
Steroid Hormones are made/synthesized by:
- produced in the smooth ER and made
up of a fused 4-ring structure. All steroid hormones
are derived from cholesterol. - all hormones produced by the adrenal
cortex (glucocorticoids, mineralocorticoids,
androgenic steroids) and reproductive organs
(progesterone, testosterone, estrogen).
Steroid Hormones act on:
- requires a protein carrier to travel
through the bloodstream due to being lipophilic.
Freely crosses the cell membrane, and binds to
receptors either in the cytoplasm or the nucleus to
form molecule-receptor complexes that bind to
DNA, and influence gene transcription. This
process is known as direct stimulation.
Freely crosses the cell membrane, and binds to receptors either in the cytoplasm or the nucleus to form _______ that bind to DNA, and influence gene transcription. This process is known as ______.
1) molecule-receptor complexes
2) direct stimulation
Steroid hormones cause ______ physiological changes.
1) slow and gradual
Amino-acid derived hormones can be made/synthesized by:
- produced in rough ER and cytosol.
Mainly derived from the amino acid tyrosine. - Can have properties that are similar to both
peptide hormones and steroid hormones.
Examples - all hormones produced by the
adrenal medulla (epinephrine and
norepinephrine, which are water-soluble). Also
includes charged amino-acid derivatives T3 and
T4 (lipid-soluble).
The hypothalamus
- coordinates the body’s
internal environment and maintains homeostasis.
The pituitary gland (hypophysis)
- is under the hypothalamus and is composed of two lobes:
1) the anterior pituitary
2) the posterior pituitary.
Posterior pituitary:
- Known as the neurohypophysis because it is
made of neuronal tissue. It is a direct neuronal
extension of the hypothalamus.
Two hormones are stored and released by the
posterior pituitary (and are produced by the
hypothalamus):
1) Antidiuretic hormone (ADH aka vasopressin)
2) oxytocin
Antidiuretic hormone (ADH aka
vasopressin)
- decreases urination by
increasing water retention. Targets
nephrons, increasing the number of
aquaporins for water reuptake.
Oxytocin
- causes uterine contractions
during child labor and the release of
milk during breastfeeding (mammary
gland). Oxytocin also plays an
important role in facilitating maternal
behavior (drive to be a good parent).
Anterior pituitary:
- Known as the adenohypophysis, it is made of
glandular tissue, and produces its own hormones.
It is connected to the hypothalamus through a
hypophyseal portal system, which allows for
quick diffusion of hormones through a portal
vein. Hypothalamic-releasing hormones are
released by the hypothalamus to stimulate the
anterior pituitary to release other hormones.
Known as the _______, it is made of
glandular tissue, and produces its own hormones.
It is connected to the _______ through a
_______, which allows for
quick diffusion of hormones through a portal
vein. Hypothalamic-releasing hormones are
released by the hypothalamus to stimulate the
_______ to release other hormones.
1) Adenohypophysis
2) hypothalamus
3) hypophyseal portal system
4) anterior pitituary
Anterior pituitary releasing hormones
- GnRH
- TRH
- CRH
- GRH
GnRH (gonadotropin-releasing hormone)
- causes release of luteinizing hormone (LH)
and follicle stimulating hormone (FSH).
TRH (thyrotropin-releasing hormone)
- causes release of thyroid stimulating hormone (TSH).
CRH (corticotropin-releasing hormone)
- causes release of adrenocorticotropic
hormone (ACTH).
GRH (growth hormone-releasing hormone)
- causes release of growth hormone (GH).
Hypothalamic-inhibiting hormones
- are released by the hypothalamus to inhibit the release of other
hormones by the anterior pituitary.
The anterior pituitary then produces its own
hormones, classified as:
1) tropic hormones
2) direct hormones.
Tropic hormones
- target other endocrine glands
for further hormone release. Important
examples released from the anterior pituitary:
1) FSH
2) LH
3) ACTH
4) TSH
FSH (follicle stimulating hormone)
- follicle growth (females) and sperm maturation
(males) in the gonads.
LH (luteinizing hormone)
- stimulates ovulation, corpus luteum formation (females),
and testosterone production (males) in the
gonads.
ACTH (adrenocorticotropic hormone)
- stimulates release of glucocorticoids from the
adrenal gland to fight stress. This also leads to
an increase in glucose levels in the body.
TSH (thyroid stimulating hormone)
- stimulates T3 and T4 production by the thyroid gland to
increase metabolism.
Direct hormones target organs directly for effects.
Important examples released from the anterior
pituitary:
- target organs directly for effects.
Important examples released from the anterior
pituitary:
1) prolactin
2) growth hormones
Prolactin
- stimulates mammary gland
development and increases milk production
after childbirth.
Growth Hormone (somatotropin)
- stimulates body cells to grow and divide.
Finally, the ______ in the brain produces
______ , which regulates circadian rhythm.
1) pineal gland
2) melatonin
The thyroid gland
- is the largest endocrine organ
and is located in front of the trachea.
3 main hormones of the thyroid:
1) T3
2) T4
3) Calcitonin
Triiodothyronine (T3)
- released in response to TSH and increases metabolism in the
body. Has a negative feedback effect on TSH secretion.
Thyroxine (T4)
- performs the same actions
as T3 above. However, T4 has one more
iodine and gets converted into T3 upon cell
uptake. It is much less potent than T3 but is
more stable in the blood.
Calcitonin
- secreted by parafollicular
thyroid cells (C cells) to decrease blood
calcium levels. Stimulates osteoblasts to use
up blood calcium to build bone and inhibits
osteoclasts. Also decreases calcium uptake in
intestines and kidneys.
Hypothyroidism
- describes the under-secretion
of T3 and T4, resulting in reduced levels of
metabolism in the body.
Hyperthyroidism describes the over-secretion of
T3 and T4, resulting in increased levels of
metabolism in the body.
- describes the over-secretion of
T3 and T4, resulting in increased levels of
metabolism in the body.
Both ______ and ______ can
lead to ______ (physical enlargement of the
thyroid gland). ______ causes
______ of TRH to compensate for ______ T3
and T4, ______ the thyroid gland, while
______ itself results from a
hyperactive thyroid gland.
1) hypothyroidism
2) hyperthyroidism
3) goiter
4) hypothyroidism
5) over-secretion
6) low
7) enlarging
8) hyperthyroidism
A goiter
- is the irregular growth of the thyroid
gland. Iodine deficiency is the most common cause
of a goiter.
The parathyroid gland
- secretes parathyroid
hormone (PTH) which performs in the opposite
way as calcitonin. It stimulates osteoclasts and
decreases calcium uptake by bones. Parathyroid
hormone increases blood calcium levels.
The pancreas
-is a gland that contains exocrine
and endocrine tissue.
Exocrine tissue
- secretes digestive enzymes
through the pancreatic duct to the small intestine.
The endocrine tissue (the islets of Langerhans)
- secretes glucagon, insulin and somatostatin.
These three hormones are each secreted by a
different cell type such as:
1) Alpha cells
2) Beta Cells
3) Delta cells
Alpha (α) cells
- secrete glucagon in response
to low blood glucose levels. Glucagon raises
glucose levels by stimulating the liver and fat
tissue to release their glucose storages.
Beta (β) cells
- secrete insulin in response to
high blood glucose levels. Insulin lowers
glucose levels by stimulating the liver,
muscle, and fat tissue to store glucose.
Insulin
-is a peptide hormone that triggers
intracellular secondary messengers to increase
glucose transporters along the cell membrane,
leading to a decrease in blood glucose levels.
Delta (δ) cells
- secrete somatostatin, which
inhibits growth hormone. It also inhibits the
secretion of glucagon and insulin.
Our body has ____ adrenal glands. Each adrenal
gland has an _____ and an _____.
They mainly help the body deal with stress.
1) two
2) outer cortex
3) inner medulla
Adrenal Cortex:
● Deals with longer term stress.
● Stimulated by secretion of ACTH from the anterior pituitary.
● Releases steroid hormones.
● Produces glucocorticoids (i.e. cortisol) to raise blood glucose levels for immediate fuel during periods of long-term stress. However, this also lowers our immune response.
● Produces mineralocorticoids (i.e. aldosterone) to increase blood volume and blood pressure by raising reabsorption of Na+. Water passively gets reabsorbed with Na+ due to osmosis.
● Produces a small amount of male sex
hormones (androgens).
Adrenal Medulla:
● Deals with short-term stress.
● Stimulated by the sympathetic nervous system.
● Releases amino-acid derived hormones.
● Produces catecholamines (epinephrine and norepinephrine) to initiate “fight or flight” response by increasing heart rate and the breakdown of glucose. Epinephrine binds both alpha (α) and beta (β) adrenergic receptors to cause vasoconstriction (alpha) and vasodilation (beta).
After stimulation by ____ and ____, the ovaries
produce ____ and ____, while the
testes produce ____ such as testosterone.
1) LH and FSH
2) progesterone
3) estrogen
4) androgen
LH and FSH: Females
● LH - during menstrual cycle, the LH surge
causes ovulation. This results in the
formation of a corpus luteum, which
produces progesterone and estrogen.
● FSH - stimulates follicle growth in ovaries,
which results in the increased production
LH and FSH: Males
● LH - triggers testosterone production by
Leydig cells.
● FSH - stimulates sperm maturation.
Hormonal control relies on ______,
which fall under positive and negative feedback
loops.
1) feedback systems
Positive feedback
- the change causes the
amplification of itself, forming a loop that
continues to intensify. You can think of it as
promoting exponential growth.
Negative feedback
- the change causes the
inhibition of itself, forming a loop that
prevents hormone overproduction. You can
think of it as promoting stability in the body.
Summary of different hormones and its release location
Page 106 DAT Bootcamp
Digestion
- is the process of breaking down large
food into smaller substances for absorption by
the body. - can occur via intracellular or extracellular digestion
Intracellular digestion
= within cells (eg: amoeba pseudopods bring food inside
its single cell for digestion).
Pseudopodia
- are temporary
protrusions of the cell membrane
found in protists for cell
movement and feeding (e.g.: amoeba pseudopods)
Extracellular digestion
- = outside of cells
(eg: humans digest food then brings
nutrients into its cell for further
processing)
Accessory organs in the digestive system include
the ______, _____, and ______.
1) pancreas
2) liver
3) gallbladder
The digestive tract has two openings:
- mouth and anus
Mechanical Digestion
- physical breakdown of food
Chemical Digestion
= chemical breakdown of food, using enzymes.
Mechanical (chewing) and chemical (salivary
amylase) digestion begin in the ______. ______ in saliva breaks down starch into ______ (glucose + glucose). Saliva also lubricates
the food, creating a ______.
1) mouth
2) Salivary amylase
3) maltose
4) bolus
Upon swallowing, food enters the ______
(common to digestive and respiratory systems) which
separates to form the ______ and the ______.
The ______ blocks the opening to the trachea,
preventing choking.
1) pharynx
2) trachea
3) esophagus
4) epiglottis
Food continues to the esophagus (tubular
structure guiding food to stomach). The bolus is
pushed down via ______ (rhythmic waves of
contraction). The ______ of the esophagus
consists of ______, the lower third
consists of ______, and the middle third
is a ______ of the two.
1) peristalsis
2) upper third
3) skeletal muscle
4) smooth muscle
5) mixture
Food enters the stomach via the ______ (ring of muscles) where ______
(churning of food) and ______ (enzymatic breakdown of protein and fat) digestion occur.
1) cardiac sphincter
2) mechanical
3) chemical
The stomach lining is filled with _______
leading to gastric glands (multiple cell types).
_______ produce mucus, which lubricates
and protects the stomach lining from the acid.
Food entry causes the stomach to _______,
signaling _______ to release gastrin, a hormone
with two functions: stimulates ________ and _______
1) gastric pits
2) mucous cells
3) distend
4) G cells
5) Parietal Cells
6) Chief Cells
parietal cells
- releases extremely acidic gastric juice (pH= 2; high
HCl concentration).
chief cells
- secretes gastric lipase (breaks down fats to fatty acids +
glycerol) and pepsinogen (a zymogen - an inactive enzyme precursor that
prevents digestion of cell itself) which activates to pepsin in acid. Pepsin cleaves peptide bonds (proteins → amino acids).
Chyme (acidic, semi-digested food) exits to the
______ via the ______.
1) small intestine
2) pyloric sphincter
the ______ is responsible for ______% of digestion and nutrient
absorption. Consists of ______ parts: ______
(digestion), ______, and______ (absorption) -
remember DJ Eye (D > J > I).
1) small intestine
2) 90%
3) 3
4) duodenum
5) jejunum
6) ileum
Goblet cells
- secrete mucus to protect the epithelial lining from acidic chyme. Chyme also triggers the release of secretin (a hormone), which stimulates the pancreas to release basic bicarbonate ions (HCO3-) into the duodenum via the pancreatic duct. Secretin is released by S-cells from the duodenum
Chyme also triggers the release of ______ (a hormone), which stimulates the ______ to release basic ______ (HCO3-) into the duodenum via the ______ .
1) secretin
2) pancreas
3) bicarbonate ions (HCO3)
4) pancreatic duct
The small intestine releases ______ in response to detecting ______ entering the ______, which ______ gastric emptying, ______ the pancreas to release digestive enzymes, and tells ______ to
release______ into the duodenum.
1) Cholecystokinin (CCK)
2) proteins and fats
3) small intestine
4) slows
5) stimulates
6) gallbladder
7) bile
Bile (emulsifies fats)
- is produced by the liver and
stored and concentrated by the gallbladder. Bile
is important for the absorption of lipids (fats)
from our diets.
The ______ secretes ______(neutralization),
______ (starch → maltose) and
______ (proteins → amino acids).
1) pancreas
2) HCO3-
3) pancreatic amylase
4) proteases
______ and ______ are pancreatic proteases, which are
initially released as______ (trypsinogen and
chymotrypsinogen). ______ in the
______ converts trypsinogen to ______, which
then converts ______ to chymotrypsin.
1) Trypsin
2) chymotrypsin
3) zymogen
4) enteropeptidase
5) duodenum
6) trypsin
7) chymotrypsinogen
Food is moved by peristalsis to the ______ and
______ for absorption. The______ connects the small intestine (ileum) to the large intestine (colon).
1) jejenum
2) ileum
3) ileocecal sphincter
______(finger-like projections which increase
surface area) are made of ______ that are
lined with microvilli. Villi and microvilli increase
______ and ______. ______ (invaginations in the intestinal wall) contain cells that secrete enzymes and produce new epithelial
cells for the lining.
1) villi
2) enterocytes
3) surface area
4) absorption efficiency
5) crypts
Inside the villus, ______ (glucose and amino
acids) are absorbed into ______ and ______
(fatty acids and glycerol) into ______.
1) nutrients
2) blood capillaries
3) fats
4) lacteals
In addition to bile production, the _____ is
involved in many processes such as:
1) liver
- Blood maintenance
- glucose metabolism
- protein metabolism
Mnemonic: Liver functions - PUSH DoG
Protein synthesis Urea synthesis
Storage Hormone synthesis DetOxification
Glucose and fat metabolism
Blood Maintenance (liver)
● Stores blood.
● Filters and detoxifies blood coming
from the digestive system via the hepatic
portal system.
● Detoxifies the body by metabolizing
chemicals and drugs, removing the
by-products as waste via bile →
intestines, and kidneys → urine.
● Destroys erythrocytes and bacteria.
Kupffer cells (phagocytes) eat bacteria
and break down hemoglobin in red
blood cells (red) to bilirubin (yellow) for
secretion in the bile.
Glucose Metabolism (liver)
● Glycogenesis - converts excess glucose
into glycogen for storage in the liver
(after meals).
● Glycogenolysis - breaks down glycogen to
glucose for bodily use (between meals).
● Gluconeogenesis - converts glycerol and
amino acids into glucose when glycogen
stores are depleted.
Protein Metabolism
● Synthesizes plasma proteins from amino
acids (albumin and blood clotting
factors).
● Converts ammonia (dangerous byproduct
of protein metabolism) into urea (safer) for
excretion.
Large Intestine: Water and mineral _____ occur at the
_____ (small pouch). The appendix (projection
in the cecum) is a vestigial structure with
negligible _____ function that can become
inflamed (appendicitis). In the _____ water
absorption is completed, hardening feces. The
feces is stored in the _____ and expelled
through the anus. Many species of bacteria
coexist in the large intestine; these bacteria serve
a critical function in _____. Over _____% of
bacteria in the large intestine are _____. These bacteria, as well as all the
other bacteria that are present in or on the body,
are collectively known as a _____.
1) absorption
2)cecum
3)immune
4)colon
5) rectum
6) aiding digestion
7) 99%
8) obligate anaerobes
9) microbiome
The large intestine has 3 functions:
- Water absorption.
- Mineral absorption (salts).
- Vitamin production and absorption: in a
mutualistic relationship, bacteria produce
vitamins B and K (absorbed), metabolize
bile acid, and ferment fiber.
Gastrin
- G cells of stomach
- Stimulate parietal cells to create gastric juice
- Stimulate chief cells to release pepsinogen + lipase
Secretin
- Duodenum
- Stimulate pancreas to release bicarbonate to neutralize acidic chyme
Cholecystokinin
(CCK)
- Duodenum
- Stimulate gallbladder to release bile
- Stimulate pancreas to release digestive enzymes (trypsin)
Salivary Amylase
- Mouth
- Digest carbohydrates to simple sugars
Gastric Lipase
- Chief cells stomach
- Digest fats to fatty acids
Pepsinogen (later
activated to pepsin)
- Chief cells of stomach
- Digest proteins to amino acids
Pancreatic Amylase
- Pancreas
- Digest carbohydrates to simple sugars
Trypsinogen +
Chymotrypsinogen
- Pancreas
- Activated to trypsin and chymotrypsin in duodenum
- Digests proteins to amino acids
Enteropeptidase
- Duodenum
- Trypsinogen → Trypsin
_______ is a key indicator of the health
of the microbiome. A healthy microbiome will have
_______ levels of all the bacteria needed for bile
acid metabolism, while an unhealthy microbiome
will not, _______ function.
1) Bile acid metabolism
2) sufficient
3) impairing
Excretion
-is the filtering out of metabolic wastes
from the body’s fluids and eliminating them as
urine.
Osmoregulation
- is the absorption and excretion
of water and solutes, so an organism can maintain
a proper water balance.
The difference between
marine fish and freshwater fish is the most
commonly used example:
- Marine (saltwater) fish. Marine fish are
hypoosmotic to their environment. They
are less salty than the surrounding
saltwater. Therefore, they’re constantly
losing water to their environment. As a
result, marine fish:
a. Constantly drink water
b. Rarely urinate
c. Secrete accumulated salts through
their gills - Freshwater fish. Freshwater fish are
hyperosmotic to their environment. They
are more salty than the surrounding
freshwater. Therefore, they’re constantly
absorbing too much water. As a result,
freshwater fish:
a. Rarely drink water
b. Constantly urinate
c. Absorb salts through their gills
Humans have _____ kidneys. Each kidney consists
of a _____ (outer portion where blood enters
the kidney), a _____ (middle portion), and a
_____ (inner portion where filtrate exits the
kidney).
1) two
2) cortex
3) medulla
4) pelvis
Functions of the kidney include:
● Regulation of blood pressure
● Regulation of blood pH
● Stimulates the generation of new red blood cells
A nephron
- is a single, functional unit of a kidney.
There are four main processes that occur in the
nephron:
- Filtration
- Reabsorption
- Secretion
- Excretion
Filtration
Filtration occurs in the cortex at the renal
corpuscle, which consists of the glomerulus and
the Bowman’s capsule. Blood enters from the
afferent arteriole into the glomerulus, which acts
as a sieve. Hydrostatic pressure forces plasma
through the sieve. Hydrostatic pressure from the
blood is the main force driving filtration in
Bowman’s capsule. Podocytes from the
Bowman’s capsule surround the glomerulus to
form fenestrations that allow small substances
(water and solutes) to be filtered into the
Bowman’s capsule while larger substances
(proteins and blood cells) remain in the blood.
The glomerulus exits the Bowman’s capsule via
the efferent arteriole, which goes on to form the
peritubular capillaries.
Filtration occurs in the _____ at the _____, which consists of the _____and
the _____. Blood enters from the _____ into the glomerulus, which acts
as a sieve. Hydrostatic pressure forces plasma through the sieve. _____ from the _____ is the main force driving filtration in Bowman’s capsule. _____ from the Bowman’s capsule surround the glomerulus to form _____ that allow _____ substances (water and solutes) to be filtered into the
Bowman’s capsule while _____ substances (proteins and blood cells) remain in the blood. The _____ exits the Bowman’s capsule via
the _____ , which goes on to form the _____ .
1) cortex
2) renal corpuscle
3) glomerulus
4) bowman’s capsule
5) afferent arteriole
6) Hydrostatic Pressure
7) blood
8) Podocytes
9) fenestrations
10) small
11) larger
12) glomerulus
13) efferent arteriole
14) peritubular capillaries
Reabsorption
Most of the reabsorption occurs in the proximal
convoluted tubule through active transport. The
distal convoluted tubule reabsorbs Na+ and Cl-.
Glucose and amino acids are two molecules that
the nephron reabsorbs almost completely. This is
because of their importance in the body.
Most of the _____ occurs in the _____ through _____. The
_____ reabsorbs _____ and _____ .
_____ and _____ are two molecules that
the nephron reabsorbs almost completely. This is
because of their importance in the body.
1) reabsorption
2) proximal convoluted tubule
3) active transport
4) distal convoluted tubule
5) Na+
6) Cl-
7) glucose
8) amino acids
Secretion
Urea, waste products, and drugs are secreted into
the nephron by active and passive transport.
The loop of Henle descends into the medulla
and has selective permeability. It is surrounded
by the vasa recta (capillaries running parallel to
the loop of Henle).
Water is reabsorbed into the blood as the filtrate
travels down the descending limb (filtrate
becomes more concentrated).
Solutes are reabsorbed as the filtrate travels up
the ascending limb (filtrate becomes less
concentrated). The ascending limb is
impermeable to water.
Secretion: _____, _____, and _____ are secreted into
the _____ by _____ and _____ transport.
1) Urea
2) waste products
3) drugs
4) nephron
5) active
6) passive
Secretion: The _____ descends into the _____
and has _____ permeability. It is surrounded
by the _____ (capillaries running parallel to
the loop of Henle).
1) loop of henle
2) medulla
3) selective
4) vasa recta
Secretion: Water is _____ into the _____ as the filtrate
travels down the _____ (filtrate
becomes more concentrated).
1) reabsorbed
2) blood
3) descending limb
Secretion: _____ are reabsorbed as the filtrate travels _____
the _____ (filtrate becomes less concentrated). The ascending limb is
_____ to water.
1) solutes
2) up
3) ascending limb
4) impermeable
Excretion
From the loop of Henle, the filtrate goes to the
distal convoluted tubule. Na+ and Cl- are
reabsorbed here, with water following passively.
The filtrate then travels to the collecting duct,
where water passively moves out and
concentrates the urine. The urine travels to the
renal pelvis and then to the ureter.
The ureter connects the kidney to the bladder,
where urine is stored. When the signal is received,
urine is excreted from the bladder and the body
via the urethra.
Excretion: From the _____, the filtrate goes to the _____. Na+ and Cl- are reabsorbed here, with _____ following passively.
The filtrate then travels to the _____, where water passively moves _____ and concentrates the _____. The urine travels to the _____and then to the _____.
The ureter connects the _____ to the _____, where _____ is stored. When the signal is received, urine is excreted from the _____ and the body via the _____.
1) Loop of Henle
2) distal convoluted tubule
3) water
4) collecting duct
5) out
6) urine
7) renal pelvis
8) ureter
9) kidney
10) bladder
11) urine
12) bladder
13) urethra
Hormones and enzymes in excretory system:
1) Renin
2) angiotensinogen
3) angiotensin 1
4) Angiotensin converting enzyme (ACE)
5) angiotensin II
6) aldosterone
7) antidiuretic hormone
8) atrial natriuretic peptide
Juxtaglomerular cells
- can detect changes in
blood pressure and volume. When blood
pressure is low, these cells release renin.
Renin
- is an enzyme which acts on
angiotensinogen to activate it to the form
angiotensin I. - Stimulation of the sympathetic nervous system
(flight-or-flight) stimulates the kidney to release
renin.
Angiotensin Converting Enzyme (ACE)
- acts on angiotensin I to convert it
to angiotensin II. Angiotensin II is the active
hormone.
Angiotensin II
- has many effects in the body to
increase blood pressure and volume. The most
important are:
● It stimulates additional aldosterone release
from the adrenal gland cortex (so
aldosterone levels increase).
● It increases Na+ reabsorption from the
proximal tubule (and water will follow the
salt).
● It is a potent systemic vasoconstrictor,
causing vessels to constrict and thereby
increasing total peripheral resistance (TPR).
● It makes the individual more thirsty: so they
drink more and increase their blood liquid
volume (increasing TPR).
Angiotensin II:
● It stimulates additional _____ release from the _____ (so
aldosterone levels _____).
● It increases _____ from the _____ (and water will follow the
salt).
● It is a potent systemic _____, causing vessels to constrict and thereby increasing _____.
● It makes the individual more _____: so they drink more and _____ their blood liquid
1) aldosterone
2) adrenal gland cortex
3) increase
4) Na+ reabsorption
5) proximal tubule
6) vasoconstrictor
7) total peripheral resistance (TPR)
8) thirsty
9) increase
Aldosterone
- is a mineralocorticoid produced by
the adrenal cortex. It increases salt and water
reabsorption and potassium secretion in the
distal tubules and collecting ducts.
Antidiuretic Hormone (aka ADH or vasopressin).
- Released from the posterior pituitary upon
stimulation from the hypothalamus. Causes
aquaporins to insert into the collecting duct of the
nephron and increases water reabsorption.
Alcohol inhibits ADH, so less water is reabsorbed,
and you urinate more.
Atrial natriuretic peptide (ANP)
- is produced by atrial cells in response to atrial distension by increased blood volume and pressure. ANP will reduce the blood volume and blood pressure.
ANP reduces blood volume and blood pressure by:
● Increasing the glomerular filtration rate (GFR), which is the rate at which the kidneys filter blood.
● Decreasing sodium reabsorption
● Increasing sodium excretion
● inhibiting renin and the renin angiotensin aldosterone system (RAAS).
The _____ has 3 layers: _____, _____, and _____. It is
involved in _____, _____ production, and _____ from pathogens.
1) integumentary system
2) epidermis
3) dermis
4) hypodermis
5) homeostasis
6) Vit D
7) protection
Epithelial cells can be either _____ (arranged in
a single layer) or _____ (arranged in multiple
layers). In terms of shape, they can be _____
(flattened),_____ (cube), or _____ (taller
than they are wide)
1) simple
2) stratified
3) squamous
4) cuboidal
5) columnar
The _____ is the most superficial layer and
contains _____. It protects against
_____, _____, and _____.
1) epidermis
2) keratinocytes
3) dehydration
4) UV radiation
5) pathogens
The stratum layers (most superficial to deep) are:
1) Corneum
2) Lucidum
3) Granulosum
4) spinosum
5) Basale
Corneum
- Corneocytes (dead keratinocytes) form the outermost, protective layer.
Lucidum*
- Dead keratinocytes that are not yet fully
differentiated into corneocytes. *It’s present in palms
and soles.
Granulosum
- Keratinocytes secrete lamellar bodies to form a water-barrier.
Spinosum
- Important for strength (desmosomes) and immunity (Langerhans cells).
Basale
- Deepest layer, the basement membrane (basal
lamina) separates it from the dermis. Attaches to
basal lamina via hemidesmosomes. Layer of the skin
that protects it from UV radiation.
Precursor keratinocyte stem cells proliferate here.
Light touch sensation (Merkel cells) and melanin
synthesis (melanocytes) occurs here.
Deepest layer, the basement membrane (_____) separates it from the dermis. Attaches to basal lamina via _____. Layer of the skin
that protects it from _____. Precursor _____ stem cells proliferate here.
Light touch sensation (_____) and melanin synthesis (_____) occurs here.
1) basal lamina
2) hemidesmosomes
3) UV radiation
4) keratinocyte
5) Merkel Cells
6) melanocytes
Located just below the epidermis, the _____
supports the epidermis and cushions against
injury. It contains 2 layers: the _____
(more superficial and thin, high surface area) and
the _____ (deeper and thick, made of
dense irregular connective tissue).
1) dermis
2) papillary dermis
3) reticular dermis
_____: made of _____, generated from hair follicles, stands up via _____, and offers sun and hypothermia protection. Only mammals have true hair.
1) hair
2) keratin
3) erector pili
Two types of Glands include:
1) Sudoriferous (sweat) glands
2) Sebaceous glands
Sudoriferous (Sweat) glands consist of:
1) Eccrine Glands
2) Apocrine glands
Eccrine glands (sweat glands)
- are located on the entire body surface and are important in
thermoregulation.
Apocrine glands
- are located at specific sites and secrete into a hair follicle. They produce earwax (ceruminous) or milk(mammary), depending on their location.
Sebaceous glands
- are located over the entire body except at the palms of hands
and soles of feet. They secrete sebum (oils + wax) into a hair follicle
The _____ (subcutaneous layer) is the
_____layer and contains _____ nerves and
blood vessels. Made of _____ tissue
and _____ (fat) tissue, its main function is_____.
1) hypodermis
2) deepest
3) larger
4) loose connective
5) adipose
6) fat storage
