Biology II (SIMPLE EDITOR) Flashcards
tight junctions: function
act as a permeability barrier – preventing transport of protein molecules from lumenal side of cell to basolateral side of cell also act to hold neighboring cells together
desmosomes: function
hold cells together
Gap Junctions: function
provides a mean for water–soluble molecules to pass from the cytoplasm of one cell to the cytoplasm of another cell
type of cells in epidermal region of skin
stratified epilthelial cells
Cells that secrete many of the proteins that make up structural connective tissue
fibroblasts
Structural proteins secreted by fibroblasts
collagen, elastin, reticulin
collagen: features and function
–triple stranded, insoluble, fibrous protein–highly cross–linked–quite strong and flexible
reticulin: features and function
–thin fiber–not as highly coiled as collagen–found in spleen and lymph nodes
elastin: features and function
–highly cross–linked protein–associated with organs that require elasticity (lungs, skin, blood vessels, etc.)
Cartilage:–type of tissue–cell type–where found
–connective tissue–special type of fibroblast = chondrocyte–fond in places where stress is put on bodies
bone:–made up of
–1/3 organic materials (such as collagen)–2/3 inorganic materials (calcium carbonate, calcium phosphate, etc.)
bone:–what secretes collagen in the bone matrix
–Specialized fibroblast cells called osteoblasts
_______ lend(s) flexibility to bones, while ________ lend(s) rigidity
–Collagen for flexibility–inorganic cystals for rigidity
Mast Cells
–Release histamines in response to an allergic reaction, infection, or injury
Effect of histamines
Cause an increase in blood flow to blood vessels in the affected region
Where are mast cells found
Respiratory tract, GI tract, etc.
Two types of cells that make up nervous system
(1) Nerve cells (neurons)(2) Support cells (glial cells)
Major anatomical features of a neuron
(1) Cell Body = integrates info(2) Dendrites = Receive info + Transmit info towards cell body(3) Axon = conducts info away from the cell body
End of a neuron = ______
synaptic bulb
Concentration of Na+ and K+ inside vs outside cell
IN CELL:small Na+LARGE K+OUTSIDE OF CELL:LARGE Na+small K+
Concentration of Cl– and HCO3– inside vs. outside of cells
Cl– = lower inside cellHCO3– = usually lower inside cell also
Typically voltage inside cell (compared to outside).Explain
Typically ~ –80mV–negative because of leaky K+ channels – so K+ diffuses outside of cell (down its gradient)
What is the ATPase Pump
Pumps Na+ out of the cell and K+ into the cell(against both of their gradients)
Nernst Equation
Vio = 2/3 (RT)/(ZF) x log([K+]o/[K+]i)
Steps to generation of an action potential:
(1) Stimulus: causes a transient increase in membrane permeability to Na+(2) Depolarization: caused by Na+ influx(3) Flood of Na+ into cell: will occur if cell is depolarized enough(4) Action Potential: generated by the flood of Na+
High level steps pre and post action potential
(1) Stimulus(2) Depolarization –> Action Potential(3) Repolarization: K+ channels open and K+ exits the cell(4) Hyperpolarization: Massive amounts of K+ exit the cell(5) Refractory Period: Na+ channels are temporarily inactive (neuron can’t generate another action potential
The generation of an action potential is an ________ phenomenon, and will always have _______
All–or–nothingWill always have the same magnitude
Two factors leading to faster and further action potentials
(1) Myelenation(2) Larger neuronal cross sectional area
Glial cells myelenate ________ (part of neuron)
Axons
Area on axons where there is no myelin
Nodes of Ranvier
Type of glial cell that myelenates the CNS
Oligodendrocytes
Type of glial cell that myelenates the PNS
Schwann Cells
Nerve impulse in myelenated neurons
Referred to as saltatory conduction “Jumps” from node to node along the axons – ions can only enter at the Nodes of Ranvier
How does an action potential spread through neuromuscular junction
(1) Action potential reaches synaptic terminal(2) Triggers Ca2+ channels to open – Ca2+ flows into synaptic terminal region(3) Synaptic vesicles fuse with presynaptic membrane – causing release of neurotransmitter (often ACh) into synaptic cleft(4) Neurotransmitter diffuses through the cleft – binding to the postsynaptic membrane receptors(5) Causing receptors to change conformation to a channel – allowing Na+ to flow in(6) Na+ flux in leads to depolarization and action potential
Excitatory vs. Inhibitory Post Synaptic Potentials
If lets in Na+ === excitatoryIf lets in Cl– or K+ ==== inhibitory
How is ACh (Acetylcholine) broken down
the enzyme acetylcholinesterase, which is bound to the postsynaptic membrane, hydrolyzes ACh into acetate and choline–Acetate and choline are transported back into the presynaptic terminal where they are used in the synthesis of Ach
Attach bone to muscle
tendon
attach bone to bone
ligaments
Muscles are made up of multinucleated _______, which are made up of ________, which are made up of ________.
Multinucleated Muscle Cells (aka Muscle Fibers) –––> Myofibrils ––––> Sarcomeres
The _______ contain the contractile units of the muscle
Myofibrils
the contractile units of the muscle = _____
sarcomeres
Sarcomeres are bound by the ________.
Z–line
Where there is only actin
I–band
the ______ contains all of the myosin
A–Band
the ______ is the region in the center of the A–Band, and it only contains myosin.
H Zone
Thin contractile protein of sarcomeres = _____Thick contractile protein = _______
thin = actinthick = myosin
_____ are arranged towards the center of the sarcomere (and not attached to the Z–Line)
Myosin
Where are myosin heads located
In the terminal regions of myosin
Actin filament is composed of a protein subunit called _______ (because the shape is _____).
G Actin (G for globular because the shape is roughly spherical)
How can actin filaments grow
by the addition of G actin to the ends of already existing filament
Each actin is composed of __________
2 rows of G actin monomers wound around each other to form a helix
High level summary of muscle contraction steps
(1) ATP is bound to myosin head (so myosin and actin aren’t bound) = relaxed state(2) ATP is hydorlyzed to ADP + Pi ––– myosin undergoes conformational change(3) High energy Myosin–ADP–Pi complex binds to actin(4) Causes release of ADP + Pi from myosin heads –– causing another conformation change of myosin ––––> Actin moves relative to myosin Called the POWER STROKE(5) ATP binds myosin – causing myosin to release actin
What causes myosin to be able to bind actin
Tropomyosin is on actin, and covers the myosin binding sitesCa2+ binds to troponin – which is attached to troponin, and causes a conformational change in tropomyosin, uncovering the myosin binding sites on actin
Relationship between action potentials and muscle contraction
Action potential travels down T–Tubules, causing release of Ca2+ from sarcoplasmic reticulum into the cytosol (where it can bind to troponin, allowing myosin to bind to actin, allowing for the power stroke)
How Ca2+ in cytosol returns to sarcoplasmic reticulum
through Ca2+ –ATPase Pump
Eqn for generation of ATP in aerobic conditions (from glucose)
Glucose –––––> CO2 + H20 + 36ATP(slower)
Eqn for generation of ATP in anaerobic conditions (from glucose)
Glucose ––––––> Lactate + 2ATP(faster)
During anaerobic conditions, [lactate] begins to ______, which will case the ph to _______. Effects of this.
[lactate] increases, and pH decreases–some enzymes can no longer function outside of pH range – halting glycolysis and ATP yield
a grouping of nerve cells = a _______
ganglian
CNS = ______PNS = ______
CNS = brain + spinal cordPNS = all nerves extending from the spinal cord
3 divisions of the vertebrate brain
(1) Forebrain(2) Midbrain(3) Hindbrain
3 Main subdivisions of the forebrain
(1) Cerebrum(2) Thalamus(3) Hypothalamus
The _______ has 2 hemispheres (right and left) which are joined by the ______.
Cerebrum (of the Forebrain); joined by the corpus callosum
The Lobes of the cerebrum (and what they are associated with)
(1) Frontal = movement and personality(2) Parietal = touch and stretch sensation(3) Temporal = Hearing(4) Occipital = Vision
Outermost layer of the cerebrum = the ______
cerebral cortex
The cerebral cortex consists of _______ and ______. Locations of both
–gray matter = nerve cell bodies + their dendrites–white matter = myelinated axons of nerve cellsWhite matter is central, gray is on outside”
Location: White and Gray matter in Cerebrum and Spinal cord
in Cerebrum:White = Central; Gray = Outsidein Spinal Cord:White = Outside; Gray = Central
3 important landmarks in cerebral cortex
(1) Central Sulcus = groove; separates frontal + parietal lobes(2) Motor Cortex = Controls movement of individual muscles(3) Sensory Cortex = Detects sensations in various parts of the body
Sensory Homonucleus
Schematic model of human being mapped out on the sensory cortex – showing which neurons register sensations from different body parts
Thalamus: function
relay station for visual and audio info
hypothalamus: function
concerned with visceral activities of the body
pituitary gland: function
master endocrine gland –receives info from hypothalamus and sends out info to regulate the body
brainstem: different features
*detects movement and can direct the head and eyes towards it–Midbrain: also senses pleasure + pain–Cerebellum: Resposible for the bulk of regulation + coordination of muscular activity–Pons and Medulla: coordinate visceral activities–Reticular Formation: brainstem core; alerts the brain + inhibits motor and sensory impulses that can induce sleep
Muscle that elicits extension (when it contracts) = ______Muscle that elicits bending/flexing = _____”
ExtensorFlexor
the nerve pathway involved in a reflex action including at its simplest a sensory nerve and a motor nerve with a synapse between = _______.Can be mono or poly–synaptic”
Reflex Arc–monosynaptic or polysnaptic reflex arcs–can include interneurons (transmit impulses between other neurons)”
efferent vs afferent divisions of the PNS
Efferent (AWAY from CNS): Carry nerve impulses:CNS –––––> MuscleAfferent (TO CNS): Carry nerve impulses:Sensory stimuli ––––> CNS
The Autonomic Nervous system is part of the ______ division of the PNS
Efferent
One part of the _________ Nervous System is the ___________ Nervous System, which can be divided into the _________ and _________ Systems.
Peripheral –––> Autonomic ––––> Sympathetic + Parasympathetic
Where do nerve fibers leave from in the Parasympathetic Nervous System?
Sacral portion of spinal cord; and midbrain and medulla
Key functions of Parasympathetic vs Sympathetic Nervous Systems
Parasympathetic = rest and digestSympathetic = fight or flight
The preganglionic nerve fibers vs. the postganglionic nerve fibers. When long and short.
In parasympathetic system:pre = longpost = shortIn sympathetic system:pre = shortpost = long
What neurotransmitters do different nerve fibers of the parasympathetic and sympathetic systems release?
Parasympathetic System:Pre = AChPos = AChSympathetic System:Pre = AChPost = Norepinephrine
Cholingeric Nerve Fibers
Release ACh (Acetylcholine)
Most prominent nerve in parasympathetic division
Vagus Nerve ~75% of all neurons in the parasympathetic division are found in the vagus nerve–innervates many organs
Sympathetic Division has nerve fibers branching off from
Thoracic and Lumbar regions of the spinal cord
How adrenal medulla functions
(1) Preganglionic nerve fibers from thoracic region of spinal cord (sympathetic division) synapse directly with nerve fibers on the adrenal medulla (i.e., there are no postganglionic nerve fibers)(2) Adrenal medulla is stimulated and releases norepinephrine and epinephrine directly into the bloodstream (thus are hormones)–––> thus it is an endocrine gland*causes increase in HR and pupils to dilate
somatic nervous system
Part of the PNS related to voluntary movements
How somatic nervous system functions
(1) Nerve fibers leave CNS and don’t synapse until they reach their effector organ(2) ACh is released(3) Innervating Skeletal Muscle(4) Can be excitatory or inhibitory
Some types of sensory receptors (and what they sense)
(1) Mechanoreceptors: Pressure; hearing; balance; blood pressure(2) Nocireceptors: Pain(3) Thermoreceptors: cold and warmth(4) Chemoreceptors: Taste, smell, O2, CO2, glucose levels, etc.(5) Photoreceptors (of retina): Photons
How sensory receptors receive, transduce, transmit, info
(1) receptor receives sensory info(2) Stimulus received changes membrane potential of receptor (transduction)(3) If potential changes enough, an action potential results
Adaptation of Sensory Neurons (and which cells adapt a lot and which don’t)
Over time, frequency of action potentials diminishes, so can no longer feel the sensation–Pressure Receptors adapt a lot, and pain do not
Receptive Field
Axonal branches of a single neuron and the many receptors that the branches end at
Three Neurons involved in sensory pathways
(1) First Order Neurons: Recetive field –––> Spinal cord. Synapses with –(2) Second Order Neurons: Ascend spinal cord to thalamus.(3) Third Order Neurons: Reach specific region of somatosensory cortex
Receptor found on postganglionic parasympathetic neuron targets (aka effector organ neurons)
Muscarinic Receptors
Receptor found on preganglionic parasympathetic neuron targets (aka the postganglionic nerurons)
Nicotinic Cholingeric Receptors
Receptor found on postganglionic sympathetic neuron targets (aka effector organ neurons)
Adrenergic Receptors
Receptor found on preganglionic sympathetic neuron targets (aka the postganglionic nerurons)
Nicotinic Cholingeric Receptors
Nerve Fibers that release norephinephrine (or epenephrine = adrenaline)
Adrenergic nerve fibers
Receptor found on cells of the adrenal medulla
Nicotinic Cholingeric Receptors
receptor found on endplates of motor neurons
nicotinic cholingeric receptors
How to number Carbons
Carbon of the Carboxyl Group (COO) = #1
autosomal dominant genetic defect
if you inherit the gene from one parent you can get the disease
Vocab:attenuate” = _____”
to reduce
Essential Amino Acids in Humans(and mnemonic device)
Valine Methionine Histidine Leucine Phenylalanine Threonine Isoleucine Lycine Tryptophan= Very Many Happy Little Pigs Take Iced Lemon Tea
What does it mean for a circulatory system to be closed?
Blood doesn’t freely mix with body flood
High level summary: blood flow starting after returning from tissues
“(1) Right Atrium(2) Right Ventricle(3) Pulmonary Artery(4) Pulmonary Veins(5) Left Atrium(6) Left Ventricle(7) Aorta ––> Arteries ––> Arterioles ––> Capillaries*(where nutrient exchange occurs)(8) Venules ––> Veins ––> Superior + Inferior Vena Cava**and then back to right atrium”
Arteries = _________ heartVeins = ___________ heart(direction)
Arteries = AWAY from heartVeins = TO heart
Blood pressure measurement steps
(1) Inflate cuff so pressure > Arterial systolic pressure —> artery collapses (stops blood flow)(2) When cuff pressure < Arterial systolic pressure, blood will flow again = “systolic pressure”-will be turbulant flow (b/c high pressure + narrow opening)(3) As relax cuff, turbulant flow will eventually disappear - instead will have laminar (smooth) flow-this is the “diastolic pressure”
Arteries are composed of what tissue types? Why?
Thick walls composed of smooth muscle and connective tissue (with elastin and collagen)–helps maintain pressure (and not be too high or low)
Endothelial cells
Blood Vessel Epithelial cells
Damage to endothelial cells = ________Lots of damage results in __________
damage = atherosclerosislots of damage = get hardening of arteries = arteriosclerosis
Arteries are important because they represent a major area of _______ in the cardiovascular system.
RESISTANCE(thus the strong walls)
Sphincter at the entrance to capillary bed; what it is composed of and what it does
Precapillary Sphincter–composed of smooth muscle which helps to regulate blood flow to the area
What allows blood to flow in only one direction in a vein?
Specialized Valves in veins = prevent backflow
Varicose beins
valve problem in veins; get backflow which increases vein pressure
Valve between right atrium and right ventricle
Right Atroventricular ValveakaTricuspid Valve
Valve between Right Ventricle and Pulmonary Artery
Pulmonary Valve
Valve between left atrium and left ventricle
Left Atroventricular ValveakaMitral Valve
Valve between left ventricle and aorta
Aortic Valve
What happens once ventricles are filled with blood
–they contract and the AV valves close (preventing backflow) = “lub”
What happens as blood flows out of the pulmonary artery and aorta
Pulmonary and Aortic Valves close = “dub”
What causes the “lub” and “dub” heart noises?”
“lub” = AV valves closing”dub” = Pulmonary and Aortic valves closing
Why don’t the AV valves invert
b/c of tendinous cords = chordae tendinae which hold them in place
What is the major pacemaker of the heart
Sinoatrial Node (SA Node)
What happens if the SA node is damaged
AV node will take over and slow the heart rate to ~40bpm
Where impulse travels from SA Node
SA Node ––> Atroventricular Node (AV Node) ––> Bundle of His, which causes ventricles to contract and eject blood
Negative Feedback loop when blood pressure is too low
Stimulus: Decrease in arteriol pressure–which means less stretch on arteries––>––baroreceptors sense this and send impulses to medulla and brainstem––>–––medulla activates sympathetic nervous system––>––––Impulses sent (via sympathetic system) cause norepinephrine (or epinephrine) release at SA Node––>–––––SA Node increases heart rate––––––Increasing heart contractions–––––––Increasing Blood pressure
Cardiac Output
=Blood Pumped Per Minute –by each of the ventriclesin Liters/MinCardiac Output = (Stroke Volume)(Heart Rate)liters/min = (liters/beat)(beat/min)
Eqn for Poiseuille’s Law
Flow = ΔPπ(R^4)/(8ηL) = (P1–P2)*π(R^4)/(8ηL)where η = viscosity ΔP = Pressure drop from 2 ends of tube R = Radius of tube L = length of tube
4 key takeaways from Poiseuille’s Law
(1) Flow is proportional to R^4–––> VERY dependent on radius!(2) Flow is proportional to the inverse of L–––> short tubes = faster flow(3) Flow is proportional to the inverse of η–––> High viscosity = slower flow(4) ΔP is what drives blood flow in the cardiovascular system
How does temperature affect diffusion
Increase Temp ––> Increased Energy ––> Increased Diffusion
Fick’s Law Eqn
J = –(D)(A)(ΔC/Δx) = –DA(Cout – Cin)/ΔxWhere J = net rate of diffusion (usually mol/s) ΔC/Δx = concentration gradient
Concentration of pure water
55.5 mol/L
What happens to the concentration of water when you add solutes? Why?
It will decrease (from 55.5 mol/L) because solute is taking up space water was taking up
How does the concentration of water change when adding one mol of glucose vs one mol of NaCl. Why?
One mol of NaCl will displace twice as much water – because it will ionize to Na+ and Cl– meaning that it will take up twice as much space, and decrease water’s concentration by twice as much
What is an osmol
1 mol that doesn’t ionize
1 M NaCl soln = ______ osmol/L
2 osmol/L
Osmolarity
The total solute concentration of a solution
What is osmotic pressure (aka πosm)–and explain in terms of the semipermeable membrane experiment
The amount of pressure that stops osmosis–osmosis will occur until the added pressure (on the side of the tank with the added protein, due to the added volume) offsets the change in concentration (since water molecules will flow to the side with the higher osmolarity – the right side, through the semipermeable membrane)
Hydrostatic Pressure
the difference in H2O levels from one side of the semipermeable membrane to the other, Δh, which is a direct measurement of the osmotic pressure
Purpose of the lymphatic system
Collects excess fluid that leaks into the interstitial space from capillaries and returns it back to the circulatory system via the vena cava
Purpose of lymph nodes
filter out foreign particles that could cause disease
What happens if a lymph node is blocked?–How does this occur after heart surgery?
Edema results = increase in interstitial fluid–after heart surgery:heart can’t pump blood fast enough –> backup in veins –> backup in lymphatic system––– as a result, edema occurs – particularly in swollen ankles and legs (fluid pools there due to gravity)
Hydrostatic pressure in the capillaries forces fluid from ________––> _________ ––> _________
Capillaries –––> Interstitial Space –––> Lymphatic Capillaries
Blood clotting occurs via a ______ which allows for _______.
Cascade Process allows for amplification
The two different pathways in blood clotting
Intrinsic Route - due to contact with some abnormal surface (e.g., “internal” damage to the blood vessel)Extrinsic Route - due to trauma of the tissue (e.g., blood vessel breaks and goes outside of the blood vessel or “external”)
Many of the factors involved in blood clotting are called _________
serine proteases
Staring with Factor Xa, describe the high level cascade leading to blood clotting
(1) In presence of Factor Xa (as well as Va, an auxiliary factor); prothrombin (which ws converted from preprothrombin –––> thrombin(2) Thrombin converts: fibrinogen –––> fibrin(3) Fibrin forms the blood clot (needs transglutimase in order to be converted to crossed–linked fibrin clot in order to do the clotting)
How is preprothrombonin converted to prothrombin
A Carboxylase enzyme (carboxylates Glu residues)–the enzyme requires Vitamin K+ and HCO3–
Why is preprothrombin converted to prothrombin?
B/c Prothrombin is a good chelating agent = it has a high affinity for Ca2+ (which is essential for blood clotting)
How do blood platelets bind the factor necessary in the blood clotting?
The negative charge on phospholipid heads on blood platelets allows γ–carboxyglutamate residues on prothrombin to bind via Ca2+–Factor Xa also has γ–carboxyglutamate residues and also binds. Xa then cuts prothrombin releasing thrombin
Why fibrinogen must be converted to fibrin
fibrinogen is large and soluble with a large negative charge (which will cause repulsion)–must release some of the negative charges (as fibrinopeptides) to get to insoluble fibrin, which has a +5 central charge (in addition to still negative charged ends) –––> now can have aggregation of fibrin monomers with one another (leading to fibrin clot)
Soft clot vs Hard clot (in blood clotting)
Soft Clot = initial fibrin clotHard Clot = there is a cross–linking via the enzyme transglutaminase (to get cross–linked fibrin clot)
Once a damaged area has been repaired via blood clotting, what happens
Plasmin (a serine protease) hydrolyzes regions in fibrin clot to dissolve it into smaller fragments (removing clot)–Tissue Plasminogen Activator (TPA) converts plasminogen to plasmin
What is dicoumarol
Vitamin K antagonist – causes abnormal prothrombin that doesn’t bind to Ca2+
What is warafarin
Vitamin K antagonist – causes hemorrhaging in rats and mice
High Level summary of how air passes down respiratory tract
(1) Oral cavity(2) Pharynx(3) Larynx(4) Trachea(5) 2 Bronchi (one to each lunch) ––– >Lungs:(6) Many bronchioles(7) MANY MANY alveoli
respiration
process by which oxygen is brought to the cells of tissues and CO2 is removed as a waste product
Composition of an alveolus2 factors leading to fast diffusion
Each alveolus consists of a single layer of epithelial cells juxtaposed to a very thin basement membrane 2 factors of fast diffusion–epithelial layer and endothelial layer of capillaries are barely separated–have millions of alveoli (large surface area)
Atmospheric Pressure at sea level = ______
1 atm = 760 mm Hg = 760 torr = 101,325 Pa
Rough makeup of Atmospheric Pressure (by molecule)
78% N221% O20.3% CO20.7% H2O
How to calculate partial pressures
Multiple the % of the pressure a molecule/gas makes up by the total pressure (partial pressures are INDEPENDENT of one another)
Why does the Partial Pressure of O2 decrease at altitude?
TOTAL pressure decreases (but O2 is still 21% of the total)
What does it mean if a gas is at equilibrium with a liquid
The # molecules dissolving into the liquid is the same as the # of molecules leaving the liquid ––> the partial pressure of the molecule/gas is the same in the gas phase as in the liquid
Total pressure of any gas is proportional to ________________.
Its concentration of molecules in the air.
What is the total pressure of air acting on membranes of epithelial cells in the alveoli of the lungs equal to?
The sum of the total partial pressures of all gases in the air
Structure of respiratory tract – how foreign objects leave the tract
Epithelial cells line lumen of passageways to bronchioles and have cilia which beat upwards.–also have mucus secreating glands.**cilia beat moving mucus and foreign objects trapped in mucus upward to oral cavity where its swallowed by reflex.
How does smoking affect respiratory system
–it decreases cilia activity while also decreasing the body’s defense against lung infections by bacteria
Type of tissue that lines upper and lower respiratory tract (and how that impacts function)
Upper passageways = maintain openings by cartilage ringsLower down (bronchioles, for ex) = smooth muscle instead
diaphragm–type of tissue–location
Skeletal muscle separating thoracic cavity and abdomen
Pleural membranes involved in breathingWhat is in between them
Visceral Pleura = covers lungs Parietal Pleura = adheres to diaphagmin between = intrapleural space = contains watery fluid
How does breathing occur (beginning with muscle contraction)
Rib Cage muscles contract and pull rib cage up+out while diaphragm muscles pull the diaphragm downward –––> thus enlarging thoracic cavity––> causes pleural membranes to move via suction – expanding lungs, creating subatomic pressure in alveoli ––> allowing for inspiration–when stop contracting, tissue returns to normal length and air in alveoli is forced out = expiration”
What would happen to the lungs without connection to visceral pleura?
lungs would collapse
What allows for diffusion of Oxygen to capillaries and CO2 to alveoli?
Pressure differences between capillaries and alveoli
The greater the pressure differences, the more diffusion there is of O2 from ________ –> __________CO2 from _________ –> _________
O2: blood in capillaries –> tissue cellsCO2: tissue cells –> blood in capillaries
How is oxygen carried in the blood
Mostly through hemoglobin; a little through diffusion
hemoglobin
transport protein in red blood cells – transports O2
Structure of hemoglobin
quaternary structure–has 4 polypeptide subunits––each has a heme group with a Fe2+ in the center––in total can bind 4 O2
What happens to O2 solubility in blood due to hemoglobin?
When hemoglobin takes up O2, more O2 can leave gas phase in alveoli and enter the blood – thus increasing O2 solubility in blood
How saturated is hemoglobin in the capillaries?–How much of this O2 does hemoglobin give up to tissues?
98% saturated with O2 in capillaries–only gives up ~25% to tissues
what happens to the O2 dissociation curve of hemoglobin when pH is decreased?–one example of when this cold occur
Curve shifts down and right–ex: exercise
–what happens to the O2 dissociation curve of hemoglobin when 2,3–BPG (a byproduct of glycolysis) binds to hemoglobin?–one example of when this cold occur
Curve shifts down and right–ex: O2 deprivation
What happens when hemoglobin O2 dissociation curve shifts?
Shifts down and right = causes hemoglobin to release more O2 to tissues at the same PO2
How is CO2 carried in the blood?
(1) 70% – in HCO3– form(2) 20% – on hemoglobin(3) 10% – dissociated in plasma and red blood cells
How does CO2/HCO3– conversion occur in tissues
(1) CO2 diffuses into RBC where it is converted to H2CO3 via carbonic anhydrase(2) H2CO3 ionizes to H+ and HCO3–(3) HCO3– diffuses into blood plasma and is carried to capillaries of lungs by circulatory system
How does CO2/HCO3– conversion occur in the lungs?
(1) HCO3– diffuses into RBC where it combines with H+ and becomes H2CO3(2) H2CO3 is converted to CO2 via carbonic anhydrase(3) CO2 diffuses into blood plasma and then diffuses into capillaries and then to the alveoli
What part of the brain coordinates breathing
Brainstem – particularly medulla and pons
How do medulla and pons coordinate breathing
Δ[H+] and Δ[CO2] –––> affect chemosensitive areas of medulla and Δ[O2] is sensed by chemoreceptors of cartoid arteries and aorta arch–––>–transmit signals to brainstem*nerve impulses from medulla and pons cause respiratory muscles to contract
bronchioles are innervated by ___________ nerves
Parasympathetic
What is asthma
hypersensitivity to airborne antigens –––> spasm and constrict smooth muscles of bronchioles
The total cross sectional area of ________ is the largest of all types of vessels in the cardiovascular system
all the capillaries
_______ regulate the flow of blood throughout the body
areterioles
Blood pressure has the highest velocity and the highest pressure when __________
After exiting the left ventricle
______________ measures turbulant flow.
Reynold’s Number.Usually turbulant when Re > 2000
Reynold’s Number Equation
Re = vdp / nwhere v = velocity d = vessel diameter p = density n = viscosity
Which walls are stronger: arterial walls or vein wallsWhich are more distensible
ARTERIAL walls are strongerthus VEIN walls are more distensible
Which walls are less distensible – systemic artery walls or pulmonary artery walls?Why?
Systemic Artery WallsB/c they are under more pressure and thus less distensible
what is the effect of blood centrifugation?
Separates plasma and Red Blood Cells –with a buffy coat in between (made up of WBC and platelets)
What is the ames test?
Ames test for mutagens:Mix suspected mutagen (a chemical) with bacteria (as well as, for example, liver extract), incubate, and see if many mutated colonies appear. If they do, the suspected mutagen is in fact a mutagen.
How many rings do purines and pyrimidines have?
Purines have 2 ringsPyrimidines have 1 ring
What about the SA node allows for it to be a pacemaker
Gradual depolarization – called pacemaker potential – which brings the membrane potential to threshold, when an action potential can occur
Alkane and alkene chemical formulas
Alkane = CnH2n+2Alkene = CnH2n
Phosphorylation = the addition of _______
Phosphate: PO4 3–
Acetylation = the addition of
Acetate: C2H3O2–
Carboxyl Group (chemical formula)
COOH
The heart rate is controlled by ____
Medulla Oblongata
Where does Transcription of mRNA from DNA occur?
the nucleus
Where does Protein Translation occur? Where does the protein go next?
- Occurs in the Endoplasmic Reticulum
- Leaves the ER in vesicles and is transported to the Golgi Apparatus for post-translational modification before being packaged so that can leave the cell
Which cellular organism do eukaryotes have but viruses, bacteria, and archae lack
Golgi Apparatus
What type of enzyme is responsible for the cleavage of phosphate bonds using water to remove a molecule of inorganic phosphate?
phosphatases
What will happen if you were to put mouse antibodies in a human?
The human would produce antibodies against the mouse antibodies (b/c it would recognize it as foreign)
If a father is non-diseased for a recessive-X-linked-disease, what is true (or could be true) about his daughter?
She must NECESSARILY by non-diseased
If a mother is homozygous for a recessive X-linked gene, what is true (or could be true) about her son?
He must NECESSARILY by affected
What are introns?
region of DNA that is removed during the processing of mRNA (e.g., AFTER transcription)
Where does transcription occur in prokaryotes
In the cytoplasm;
so ribosomes can bind and begin translation before transcription is complete
What is nondisjunction?
-The failure of homologous daughter chromosomes to separate during anaphase I of meiosis
OR
-The failure of sister chromosomes to separate during anaphase II of meiosis
Mistranslation of codons will likely increase ______ (in proteins)
protein misfolding
“high affinity transport”
vs
“high transport capacity”
“High affinity transport” = transporter has a high affinity for a particular substrate (so will bind even when have low [substrate])
“High transport capacity” = transporter can transport a lot of the substrate (so if have high [substrate], the transporter will be able to transport a lot])
Kt depends on what (and not on what)?
enzyme kinematics
-Is a property of the transport protein itself. Does NOT depend on the concentration of the transport protein.
Kt depends on what (and not on what)?
enzyme kinematics
-Is a property of the transport protein itself. Does NOT depend on the concentration of the transport protein.
What is the Michaelis Menton Equation
V(0) = V(max)*[S} // K(m) + [S]
What is the Lineweaver Burk Plot eqn?
- slope
- y-intercept
- x-intercept
1 // V[0] = (K(m)/V(max))*(1/[S]) + 1/V(max)
(y = mx + b)
y-intercept = 1/V(max) slope = K(m) / V(max) x-intercept = -1/Km
Compare the three types of enzyme inhibitors
(1) Competitive inhibitor:
- binds to free E
- increases Km, Vmax is same (so in LW plot, slope increases, but y-int is same)
(2) Uncompetitive inhibitor:
- binds to ES complex
- decreases Vmax (in LW plot, slope is the SAME, but y-int increases)
(3) Noncompetitive (“mixed”) inhibitor:
- binds to ES or free E
- Vmax decreases, Km increases (in LW plot, slope increases, and y-int increases also)
Kcat
= Vmax / [E]t
-is equal to the turnover # (# of rxns / s)
Calculating enzyme catalytic efficiency
catalytic efficiency = Kcat / Km
What is Km equal to
(1/2) Vmax
cytochrome c
A heme protein that only cycles between a ferrous and ferric state during oxidative phosphorylation —> thus a 1-electron carrier
What isomeric form of amino acids are used to form proteins during ribosomal protein synthesis
ONLY the L-isomers
How many ATP molecules are formed per molecule of glucose….
- under aerobic conditions
- under anaerobic conditions
- aerobic = use cellular respiration; 38 ATP produced
- anaerobic = use fermentation; 2 ATP produced
What are the 3 types of protein filaments that make up the cytoskeleton
(1) microfilaments (aka actoin filaments)
(2) Intermediate filaments
(3) Microtubules
What type of filaments are actin filaments?
Microfilaments
Path of blood flow after heart and then back to heart
- Heart –>
- Aorta –>
- Arteries –>
- Arterioles –>
- Capillaries (and out to tissues) –>
- Venules –>
- Veins –>
- Inferior or superior vena cava –>
- Heart
What would happen if someone had fewer visual pigments?
Fewer signals would be sent to the brain
How many visual pigments are there (what are they?)
3, which absorb
- red
- green
- or blue light
What does Brown Adipose Tissue contain a large number of (and what does it do)
Large number of mitochondria that generate heat during thermogenesis
In the absence of oxygen, what happens to pyruvate (instead of ___)?
-Pyruvate is converted into lactate in the cytoplasm and is NOT transported to the mitochondria to be converted to acetyl-CoA
If a genome were to be 23% Adenine, what would it be of G, C, and T
23% T
(100% - 2*23%) = 54%; 54%/2 = 26%, so
27% G
27% C
Basic structure of fatty acids
- Carboxylic head group and
- a hydrocarbon tail
Systemic veins carry _____ levels of CO2 and systemic arteries carry ______ levels of CO2
—what does this say about HCO3- conc?
- Veins = HIGH CO2
- Arteries = LOW CO2
-same for HCO3-
How do gases enter and exit the RBC
Through diffusion across the RBC plasma membrane.
What is a benefit of RBCs not containing nuclei (why don’t they contain nuclei)?
- More room for hemoglobin, so more oxygen can be taken up
- RBCs push out their nuclei
What is a lysosome
an organelle in the cytoplasm of eukaryotic cells containing degradative enzymes enclosed in a membrane.
What is the pathway of endocytosis?
Early endosomes –> late endosomes –> lysosomes (to degrade the material)
-can have vesicles pass between the Golgi and endosomes in both directions
Helices are a type of ____ structure
Secondary strcuture
What is a lysozyme
an enzyme that degrades the wall of bacteria (causes lysis)
The LOWER the Kd value, the _____ the affinity for the antibody
HIGHER
What is Kd for atibodies?
The equilibrium dissociation constant
- a ratio of koff / kon between the antibody and its antigen
- Kd and affinity are inversely related
What do proteases do?
Enzymes that perform protein catabolism by hydrolysis of peptide bonds
What is an operon?
A functioning unit of genomic DNA containing a cluster of genes under the control of a single promoter
Most of the lining of the mouth is derived from what type of germ layer?
Invagination of ectoderm
Most epithelial tissue inside the body is derived from what germ layer?
Endoderm
What type of tissue makes up the bronchi, bladder, stomach, etc.
Epithelial tissue
what is chelation
a type of bonding of ions and molecules to metal ions (such as Ca2+)
Blood contains many more (WBC/RBC) than (WBC/RBC)
Many more RBCs than WBCs
How is turbulent flow measured?
Using Reynold’s # (usually Turbulent when Re>2000).
Re = vd/(n/p)
where v = velocity, d = vessel diameter, n = viscosity, and p (row) = density
Structure of purines vs pyrimidines
purines have 2 rings, and pyrimidines have 1 ring
Number of Oxygens on the nitrogenous bases
G & C = each have 1 oxygen
T (or U) = 2 oxygens
A = 0 oxygens
Chemical structure of
-alkanes vs. alkenes
Alkanes (non-cyclical) = CnH(2n+2)
Alkenes (non-cyclical) = CnH(2n)
Cellulose
glucose polysaccharide found in plant walls
Cellulase
enzyme that hydrolyzes cellulose to release glucose
-humans don’t have cellulase so can’t digest cellulose
Starch and glycogen
Important polysaccharides in nature
Amylases
hydrolyze starch and glycogen to release glucose
What type of animals can digest cellulose
Animals with a rumen - which contains microorganisms that secrete cellulase (an example of a symbiotic relationship)
Proteases
enzymes that hydrolyze proteins to their constituent amino acids
enzymes that hydrolyze proteins to their constituent amino acids
proteases
lipases
enzymes that hydrolyze fat (aka triglycerides; which is stored in adipocytes) into fatty acids + glycerol
enzymes that hydrolyze fat (aka triglycerides; which is stored in adipocytes) into fatty acids + glycerol
lipases
where are triacylglycerides stored?
adipocytes
Vitamins
Molecules needed in only small amounts, but are essnetial
Essential amino acids
the 9 (of the 20 basic amino acids) that humans need to obtain in our diet (the rest humans can synthesize
5 general components to a complete diet
(1) Carbohydrates (in sugar form)
(2) Fats
(3) Protein
(4) Vitamins
(5) Minerals
Inner layer of the small intestine
- made up of - features
- epithelial cells
- convulated for increased surface are digestion
- external exocrine glands (from pancreas/liver/etc.) are scattered here)
- also ave endocrine cells that release hormones
How does the lower GI tract contract as food passes through?
- Smooth muscle (surrounding the epithelial cells) contracts in peristaltic waves - controlled by parasympathetic system and hormones)
- fast due to gap junctions in circular and longitudinal muscles of GI tract
What enables quick peristaltic action in the lower GI tract
electrical continuity imposed by the gap junctions in the circular and longitudinal muscles of the GI tract
salavary amylase
begins digestion
-digests starch and glycogen (carbohydrates)
Epiglottis
tissue flap covering larynx opening so that food doesn’t enter, and instead food enters esophagus and then goes to stomach
the swallowing reflex is controlled by the _____
medulla
What contracts to prevent regurgitation of food back to the esophagus?
gastroesophageal sphincter
Functions of the stomach
(1) Break food down to smaller particles
2) detoxify food (by acidic secretions
What are the 4 major types of stomach secretions? (and what type of cells secrete them)
(1) Mucus = (by surface cells); protects lining of stomach and lubricates the food
(2) Gastrin = (by endocrine cells); secreted in response to protein entering the stomach; stimulates the secretion of pepsinogen and HCl
(3) HCl = (by parietal cells) pH ~ 1; converts pepsinogen -> pepsin. Once pepsin is formed, pepsin can also convert pepsinogen -> pepsin
(4) pepsinogen = (by chief cells); inactive form of the peptidase enzyme pepsin
What stimulates secretion of HCl and pepsinogen
gastrin
What do chief and parietal cells do?
Chief Cells –> Secrete pepsinogen (in stomach)
Parietal Cells –> Secrete HCl (in stomach), and also intrinsic factor (a glycoprotein)
intrinsic factor
- A glycoprotein secreted by parietal cells in the stomach
- complexes with Vitamin B12 and is then absorbed by intestinal epithelial cells and transported by bloodstream (without intrinsic factor, would be deficient in Vitamin B12 - which is necessary for RBC formation)
Why do ulcers occur in the stomach?
-if too much acid is secreted into the stomach
histamine and the stomach
histamine stimulates the release of HCl into the stomach.
Cimetidine drug
inhibits histamine from binding to parietal cells (in the stomach), thus inhibiting their release of HCl into the lumen of the stomach
Where does the majority of digestion occur?
90% of digestion occurs in the small intestines
Acidity of small intestine?
Small intestine neutralizaes the acid secreted by the stomach
Cholecystokinin (CCK)
- Small intestine distension causes its release
- diffuses through bloodstream to pancreas, where it causes pancreas to release digestive enzymes
Secretin
a hormone released by the small intestine in response to entering chyme from the stomach
-transported by bloodstream to pancreas - causing it to release bicarbonate ion and other fluid
CCK and Secretin
- why released
- effects
CCK:
- released when small intestine distends
- causes pancreas to release digestive enzymes
Secretin:
- released when chyme enters small intestine from stomach
- causes pancreas to release bicarbonate ion and other fluid
acini
- structures in the pancreas
- secrete fluid into small intestine that has a high bicarbonate content —> the bicarbonate ions will combine with HCl to produce carbonic acid, which is converted to CO2 and H2O –> will cause the pH in the small intestines to increase
Main secretions from pancreas
- insulin and glucagon (from endocrine cells)
- Bicarbonate ion (from acini strucutres)
main function of liver
-synthesizes bile (which is stored in the gallbladder)
bile
- where synthesized
- where stored
- synthesized in liver
- store in gallbladder
Effects of presence of fat in small intestines
- causes release of CCK by the small intestine
- CCK release causes gallbladder to contract and sphincter of oddi to relax —> resulting in bile passing into lumen of small intestine
What is the major pigment in bile (and what is it)
bilirubin - a breakdown product of hemoglobin
What are bile salts
contained in bile; important in fat digestion and absorption
Process of bile release (and what it does afterwards)
- Bile is released from gallbladder and passes through a duct that joins with the pancreatic duct through the sphincter of odd, and empties in the small intestine
- there it emulsifies fat and helps epithelial cells absorb fat
sphincter of oddi
a muscular valve that controls the flow of digestive juices between the liver/pancreas and the small intestine
Transport proteins in the small intestine
- where located
- function
- located on apical (lumen side) and basolateral (blood side) regions of the epithelial cells in the small intestine
- allow the absorption of many compounds, including Na+, glucose, minerals, etc.
Cholera Toxin
caused by massive loss of fluid by diarrhea
osmosis and the small intestines
Water diffuses into the lumen through osmosis
Main function of large intestine
- absorb most of water ad ions left in chyme as it passes from the small intestine
- what’s not absorbed passes in feces
Chylomicrons
- formation of
- where they go
- fatty acids and glycerol diffuse into intestinal epithelial cells where they are resynthesized into triglycerides - and aggregate into chylomicron structures
- chylomicrons are released into the basolateral membrane. They enter into lymph and are transported to the veins and eventually the tissues.
Where is the water in the human body distributed
- 2/3 of water is in cells (intracellular fluid)
- 1/3 of water is in the interstitial space (extracellular fluid)
How is water lost in the human body
- integuement (the skin, via evaporation)
- GI Tract
- lungs
- urinary system
The water lost from the body exactly matches _______
the water gained by the body by fluid consumption and regulation at the level of the kidneys
osmoconformers
Organisms that can change internal ionic concentration of its body fluids to meet that of surrounding environment
osmoregulators
Organisms that DON’T change their internal ionic concentration to meet that of their environment
Three main functions of vertebrate kidneys
(1) Filtration
(2) Reabsorption
(3) Excretion
How does filtration occur in the kidney (high level)
through the nephron: the functional unit of kidney. Which consists of a:
- glomerulus (collection of capillaries that receives blood from an artery terminating at the renal system
- bowman’s capsule
- tubular system
*blood is pumped into the glomerulus by the hydrostatic pressure of the heart, and that pressure forces the blood through the capillary walls and into Bowman’s capsule. (the cell-free ultra-filtrate in Bowman’s capsule lacks many of the plasma proteins found in blood
How does reabsorption occur in the kidney (high level)
Through many of the epithelial cells that line the tubular lumen of the nephron
- cilia of the epithelial cells propel filtrate through renal tubes
- glucose, small proteins, amino acids, salts, bicarbonate ions, and water and reabsorbed by the tubes and transported back to the blood
- epithelial cells can also secrete protons, K+, urea, uric acid, and ammonia
Where does blood enter the kidney from
-Blood from the descending aorta enters the renal artery and eventually enters the glomeruli
Where does blood leave the kidney from?
-by the renal vein, which empties into the inferior vena cava.
Where does urine exit the kidney from (and where does it go)
-the ureter transports urine to the bladder, where it exits via the urethra
Cortex vs. Medulla (or kidney)
- Glomeruli and bowman’s capsule are in the cortex, so it is granular in appearance
- medulla is striated and contains the loop of henle and the collecting ducts (which collect urine and empty into renal pelvis of kidney and then the ureter)
As renal artery enters the kidney, what happens to it?
It branches and becomes the afferent arterioles - which enter bowman’s capsule and form the glomerulus
What leaves the glomerulus and forms capillaries surrounding renal tubules?
- the efferent arteriole
- the blood that leaves the capillary network does so through a venule which empties into the renal vein that leaves the kidney
What extends from Bowman’s capsule (in order)?
(1) Proximal convoluted tubule (PCT)
(2) Loop of Henle
(3) Distal Convoluted Tubule (DCT)
(4) Collecting Duct
What is the osmolarity of filtrate in Bowman’s Capsule (and what is it equivalent to)?
~ 300 milliosomols = that of filtrate in PCT = that of plasma
What is dilute urine vs. concentrated urine
Dilute urine = osmolarity < that of filtrate in Bowman’s capsule, PCT, and plasma (<300 momols)
Concentrated urine = >300 mosmol
What is the PCT, and what are its functions and features
= Obligatory section of nephron (b/c it is where ~65% of all reabsorption and secretion occurs)
- epithelial cells are very metabolically active –> so have active transport
- many reabsorption methods require Na+
- All glucose, small proteins, Amino Acids, and Vitamins are reabsorbed here, as are most ions and water
- little regulation occurs here
Segments of Loop of Henle
(1) Thin Descending
(2) Thin Ascending
(3) Thick Ascending
Function: Thin descending loop of henle
Very permeable to H2O, but only relatively permeable to ions and molecules
Function: thin ascending loop of henle
More permeable to urea, less permeable to H2O
Function: thick ascending loop of henle
- Actively transports ions to interstitial fluid from lumen of loop
- impermeable to urea and water (so filtrate is becoming less dilute)
High level: ion and water concentration in kidney medulla (due to loop of Henle)
- loop of henle makes the medulla very SALTY.
- the ascending loop pumps out the salts
- the descending loop, which is permeable to water - has water diffuse out since the medulla is salty —> in this way, the saltiness allows water to leave the loop into the medulla
Distal Convoluted Tubule:
-segments and functions of each segment
(1) segment close to loop –>
- impermeable to urea and H2O, but permeable to ions (Na+, etc.) –> filtrate becoming more dilute
(2) segment close to collecting duct & portion of collecting duct in cortical region of kidney –>
- impermeable to urea
- sensitive to hormone aldosterone and ADH
aldosterone
- secreted in cortex by adrenal glands
- regulates Na+ concentration
- increased aldosterone –> Na+ is reabsorbed by epithelial cells (and K+ is simultaneously pumped into nephron lumen)
Antidiuretic Hormone (ADH)
- Produced by hypothalamus and released by posterior pituitary
- regulates water consumption
- increases ADH —> water reabsorbed from epithelial cells in collecting duct and passed into interstitial Fluid (concentrates urine, by removing water from the urine)
Homeostatic maintenance of Na+ concentration
-decreased Na+ ==> cells in adrenal cortex release aldosterone ==> causes DCT and collecting duct to reabsorb Na+
Homeostatic water maintenance
-decrease in plasma volume ==> decrease in Blood pressure, which is detected by osmoreceptors ==> hypothalamus synthesizes and transmits ADH to posterior pituitary where it is released to blood ==> ADH causes DCT and collecting duct to reabsorb H2O
Effects of alcohol use on water homeostasis
-Alcohol inhibits ADH
Main source of nitrogenous waste in the bod
Proteins and nucleic acids
3 Ways to remove nitrogen waste (as):
(1) Ammonia
(2) Urea
(3) Uric Acid
Ammonia vs. Urea vs. Uric Acid
Ammonia
-toxic & soluble
-in fish, glutamine is converted to ammonia which combines with a proton and is excreted (mammals can also excrete ammonium)
______________
Urea
-less toxic & soluble
-exreted by mammals (in urine; is a glutamine byproduct)
_______________
Uric Acid
-toxix & insoluble
-excreted by birds and reptiles (ammonia is converted to uric acid)
Normal pH of body
~7.4
How is body pH regulated
through buffering system –> H+ bound to buffer (such as HCO3-)
Cholera Toxin
Acute intestinal infection transmitted in contaminated food/water
-leads to rapid fluid loss
What type of hormone is norepinephrine
An amine hormone
-specifically, a catecholamine
What type of hormone is epinephrine
An amine hormone
-specifically, a catecholamine
What type of hormone is dopamine
An amine hormone
-specifcally a catecholamine
What type of hormone is aldosterone?
A steroid hormone
- more specifically, a corticosteroid
- even more specifically, a mineralocorticoid
What type of hormone is insulin?
a peptide hormone
What type of hormone is glucagon?
A peptide hormone
What type of hormone is cortisol?
A steroid homone
- more specifically, a corticosteroid
- even more specifically, a glucocorticoid
Two subroups of steroid hormones (and the five subtypes that fit into the two subgroups)
(1) Corticosteroids
- Glucocorticoids
- Mineralocorticoids
(2) Sex Steroids
- Androgens (such as testosterone)
- Estrogens
- Progesterone
Hypertonic solution
Having a higher osmotic pressure than a particular fluid (typically body fluid or intracellular fluid)
Water moves from a region of _____ osmotic pressure to a region of _____ osmotic pressure
From low —-> high
What hormone is responsible for taking fat from the vascular system and facilitating its uptake into adipose tissue
Insulin
Parietal cells secrete ______ into _____ and also _____ into _______.
secrete H+ into the intestinal lumen and bicarbonate into the blood
pancreatic cells release bicarbonate into ______ along with _____ into _____
Bicarbonate into the intestinal lumen along with H+ into the blood
GnRH
Gondadatropin releasing hormone, released by the hypothalamus, causes the anterior pituitary to release gonadatropins (which go to the gonads)
Gonadatropins
- what
- released by what (and why)
- cause
- Luteinizing Hormone (LH) & Follicle stiulating hormones (FSH)
- released by the anterior pituitary, caused by release of GnRH by the hypothalamus
- stimulate the gonads - to produce steroid hormones and germ cells (ova or spermatazoa)
seminiferous tubules
series of convoluted tubules in testes
-where sperm is produced
where are sperm produced (and why?)
in Testes - which lies in scrotum, which is outside of the body cavity
-b/c sperm formation requires a lower temp (than body temp)
What is the process between spermatagonia and spermatazoa
starts at basement membrane of semineferous tubules _____
(1) Spermatagonia 1(2n) —mitosis—>
(2) Primary spermatocytes 1(2n) —-meiosis I–>
(3) Secondary spermatocytes 2(1n) —meisosis II–>
(4) Spermatids 4(1n) –transformation–>
(5) Spermatazoa 4*(1n)
What are the primary things occurring in the testes?
____
-cells related to each thing
(1) Sperm is produced (in semineferous tubules) [by spermatogenic cells]
(2) Leydig Cells synthesize testosterone (outside of tubules)
(3) Sertoli cells promote spermatagenesis and produce inhibin protein hormone (in tubules); sertoli cells are in constant contact with spermatagonic cells
Cytoplasmic Bridges in the semineferous tubules
Connect the spermatids
Acrosome
- tip of sperm
- has digestive enzymes that help gain access to egg interior after fertilization
Where are the DNA and mitochondria of the sperm?
- DNA = in head of sperm
- mitochondria = in midsection
function of mitochondria in sperm
-provides energy to tail so can swim
How is testosterone formed
Leydic cells convert cholesterol —> testosterone
Testosterone’s 2 main roles
(1) Can move into target tissues
(2) Can diffuse into Sertoli cells - where it binds to a receptor and is converted to dHT (dihydrotestosterone), which diffuses into nucleus of sertoli cells and instructs DNA to produce RNA (which affect spermatagoneic cells)
Function of LH in males
-binds to receptor on Leydig Cell, producing secondary signal —> increases conversion of cholesterol to testosterone
FSH Function in males
-Binds to receptor on Sertoli Cell and induces secondary response –> helps convert testosterone to dHT (and also induces the synthesis of the receptors)
How is GnRH inhibited (in males)?
-Testosterone inhibits GnRH
How is LH inhibited (in males)
-Testosterone inhibits LH
How is FSH inhibited (in males)
-Inhibit inhibits FSH
Sperm Travel
SEVEN UP (1) Seminiferous Tubules (2) Epididymus (3) Vans Deferens (4) Ejaculatory Duct N=nothing (5) Urethra (6) Penis
what makes up semen?
Small part sperm, the rest is secreted by:
-seminal vesicles
-prostate gland
-bulbourethral glands
(fructose, vitamins, zinc bicarb, prostagalandins, mucus,, etc.)
How long can sperm live in the vagina?
~48 hours
Sperm travel in females
(1) Vagina ->
(2) Oviduct (aka fallopian tubes) = site of fertilization.
Once have a fertilized egg:
(3) Egg implants in uterus - in uterine lining - ~1 wk after ovulation. Continues to grouw here until delivery
What is the egg called once it implants in the uterus
a blastocyst
Oogenesis vs spermatogenesis
2 main differences
(1) spermatogenesis yields 4 identical sperm, oogenesis yields 1 egg (and 2 polar bodies)
(2) Mitosis ceases within 2-3 months of fetal development in females –> so females are born with all the primary oocytes she’ll ever have (males continue producing primary spermatocytes)
What happens to the primary oocytes
Most degrade –> called atresia
-the rest will mature
Oogenesis (beginning to end)
(1) Oogonia 1(2n) –mitosis–>
(2) Primary Oocyte 1(2n) –Meiosis I—arrested in prophase, monthly with a surge of LH continues–>
(3) (first polar body) + Secondary Oocyte 1(1n) —Meiosis II—arrested in anaphase, only after fertilization continues—>
(4) (second polar body) + zygote 1(2n)
Primary follicle
a primary oocyte surrounded by a layer of follicle cells. Eventually 1 ill start to develop
follicular phase
- what it is
- how long
pre-ovulation, when primary oocyte matures
-lasts up to the ~14th day of woman’s monthly cycle
Zona pellucida
membrane surrounding primary oocyte - is surrounded by more follicle cells called granulosa cells and thecal cells
Theca Cells are the female equivalent of _____, and granulosa cells are the female equivalent of _____.
Theca = leydig Granulosa = Sertoli
What are the main events of the folliclar phase
(1) Fluid builds up in the primary follice, forming the antrium
(2) LH surge causes meiosis I - forming secondary oocyte - and production of enzymes that break down membrane on primary follicle
(3) after secondary oocyte is released, ovulation occurs (the beginning of the luteal phase)
Luteal phase
-what and when
After 14th day of monthly cycle, starts at ovulation and lasts until menstrual flow.
Main events of luteal phase
(1) Begins at ovulation
(2) Leftover follicle is transformed into corpus luteum which produces estrogen and progesterone
(3) Corpus luteum degenerates if no fertilization and cycle starts again (thus Luteal phase ends at the beginning of menstrual flow)
LH and FSH and estrogen levels during woman’s monthy cycle
(1) LH levels are flat until LH surge just before ovulation
(2) LH Surge also has an FSH surge with it (although not as much)
(3) estrogen surges before ovulation and then a little afterwards
(4) the increase in estrogen will lead to an increase in LH
What do theca cells do?
Convert cholesterol to testosterone in females
Testosterone in females?
- synthesized by theca cells from cholesterol
- diffuses into follicle cells and is converted to estrogen, which helps to develop the primary follicle
