Biology 2 Flashcards
Endocrinology
- Name and describe the TWO Homeostatic control mechanisms include reflex loops in which the response decision is made at a distance from the target cell.
- Name and describe the other TWO homeostatic control mechanisms ie the local response in which the signal and action occurs close to or at the target cell
- Endocrine: hormone reaches its site of action via the blood circulation.
Neuroendocrine: hormone is secreted from neurons into the blood to act at a distance
2.Paracrine: cytokine is secreted into the interstitial fluid to act locally on target cells.
Autocrine: cytokine is secreted into interstitial fluid to act on the cell that produced it
Senses
- How does the central nervous system, receiving signals from afferent receptors, know how intense a sensation is?
Frequency of action potentials.
- If the blood pressure doubled at the same time that the peripheral resistance were doubled, the blood flow through a vessel would be:
C. 16 times greater
D. 1/16 as much
B. halved
A. doubled
E. unchanged
E. unchanged
Well done!
- Total peripheral resistance decreases in a runner during strenuous exercise due to:
A. increased parasympathetic nervous stimulation of the working skeletal muscle
B. increased vasoconstriction of the large veins of the body
C. increased metabolites in the IS surrounding the muscle
Answer 2: C. increased metabolites in the IS surrounding the muscle
Cell membranes - water transport
- Osmosis - what happens to compartment size when the membrane is impermeable to the solute?
eg compartment A has 1L water and 2 Na+ ions, B has 1L water and 4 Na+ ions
Osmosis causes change in compartment size when the membrane is impermeable to the solute
eg end up with A say 500mL water and still 2 Na+ ions, B 1.5L water and still 4 Na+ ions
Jake is floating on the surface of a lake and breathing through a snorkel.
Does he need to increase his tidal volume to keep his alveolar ventilation normal?
Yes.
No
Yes
When is PAO2 highest in the lung?
end of expiration
end of inspiration
mid expiration
mid inspiration
end of inspiration
In a patient diagnosed with emphysema, the:
A. lung elastic recoil is greater than normal due to damage of elastic fibers.
B. functional residual capacity is greater than normal due to increased lung compliance.
C. airway compression during forced expiration is less than normal because pleural pressure decreases more than it does in a normal individual.
D. total lung capacity is less than normal due to increased lung compliance.
B. functional residual capacity is greater than normal due to increased lung compliance.
A decrease in blood pH will _________ the rate of breathing.
increase
decrease
not change
increase
- If two liters of blood are lost from the body, arterial hypotension occurs.
This can lead to the movement of fluid from the tissues into the capillaries in response to:
A. Higher capillary hydrostatic pressure
B. Lower capillary hydrostatic pressure
C. Higher capillary oncotic pressure
D. Lower capillary oncotic pressure
Answer 3: B. Lower capillary hydrostatic pressure
Neurons
- How are signals integrated by a post synaptic neuron?
(text + diagram of three pre-synaptic neurons firing)
The presynaptic neuron causes a graded potential to occur in the postsynaptic neuron.
The graded potential can depolarize the postsynaptic membrane, which makes the potential closer to threshold, and is called an excitatory postsynaptic potential (Figure 26, synapses 1 and 2).
Alternatively, the graded potential can hyperpolarize the postsynaptic membrane, which makes the membrane potential farther from threshold, and is called an inhibitory postsynaptic potential (Figure 26, synapse 3).
Since presynaptic neurons cause graded potentials in postsynaptic neurons, spatial and temporal summation of signals from multiple synapses can occur so the postsynaptic neuron can integrate information
Neurons
- What affects the speed of an action potential?
- Myelination and diameter (larger is faster)
The diameter of an axon also determines how quickly action potentials travel down its length.
Larger diameter axons have less resistance so action potentials travel more quickly along their length. This is exploited by the body.
Neurons that sense touch have large diameter axons while pain and itch neurons have small diameter axons
Muscle
- What is excitation-contraction coupling?
E-C coupling (excitation-contraction coupling) (Figure 44) refers to the electrical events which trigger a contraction. Each skeletal muscle is innervated by an alpha motor neuron. An action potential arriving at the neuromuscular junction releases the neurotransmitter acetylcholine from the
Bone joints
- Describe the types of joints (how they connect, not articulation)
Fibrous This type of joint is held together by only a ligament. Examples are where the teeth are held to their bony sockets and at both the radioulnar and tibiofibular joints.
Cartilaginous These joints occur where the connection between the articulating bones is made up of cartilage for example between vertebrae in the spine
Synovial joints are by far the most common classification of joint within the human body. They are highly moveable and all have a synovial capsule (collagenous structure) surrounding the entire joint, a synovial membrane (the inner layer of the capsule) which secretes synovial fluid (a lubricating liquid) and cartilage known as hyaline cartilage which pads the ends of the articulating bones.
There are 6 types of synovial joints which are classified by the shape of the joint and the movement available
Acid-base
- What is the Henderson-Hasselbalch approximation used for?
- Write the equation
The Henderson-Hasselbalch approximation allows us one method to approximate the pH of a buffer solution
pH = pKa + log ([A−] / [HA])
HA is the acid, A- is the conjugate base
Which of the following arterial blood pressures (mmHg) has the largest pulse pressure?
A 130/85
B 120/90
C 115/75
D 125/70
D 125/70
Cardiac muscle
- Describe the three steps in the ELECTRICAL – CONTRACTION (E-C) COUPLING in cardiac muscle
ELECTRICAL – CONTRACTION (E-C) COUPLING
As in skeletal muscle, contraction in cardiac muscle is dependent on the entry of Ca++ from the T tubule (Figure 51).
- Depolarization of the T tubule membrane opens the voltage gated Ca++ channels (dihydropyridine receptor), permitting the entry of a small amount of Ca++.
- This Ca++ opens the Ca++ gated Ca++ channel (ryanodine receptor) on the sarcoplasmic reticulum (SR) thereby releasing a lot of Ca++ into the cytoplasm.
- In turn, Ca++ binds to troponin which unmasks the actin (thin filament), cross bridges form, and shortening occurs.
With repolarization of the T tubule membrane, no further Ca++ enters the cells and the SR CaATPase removes Ca++ from the cytoplasm. This removal of Ca++ ends the contractile cycle and the muscle relaxes
- Vascular resistance is related to the:
B. diameter of a blood vessel
D. viscosity of the blood
A. length of a blood vessel
C. nature of the blood flow (turbulent vs lamellar)
E. A, B, C, and D
E. A, B, C, and D
Well done!
Two types of lower motor neurons
- During muscle contraction what are coactivated?
Two types of lower motor neurons
The portion of a skeletal muscle that controls posture and movement, the extrafusal muscle fibers, are innervated by alpha motor neurons.
A specialized type of skeletal muscle fiber, the intrafusal muscle cell, resides in the muscle spindle in the interior of the muscle (Figure 38). The intrafusal muscle fibers are innervated by gamma motor neurons.
During muscle contraction, alpha and gamma motor neurons are coactivated.
Stretching of the intrafusal fibers in the muscle spindle is sensed by stretch receptors and sent via afferent sensory neurons to the spinal cord. This allows for monitoring of the length of the muscle which helps control muscle tone.
Cell membrane pumps
- How do they move solutes? (in terms of concentration)
- What energy do pumps use - if any?
- From [low] to [high]
- Pumps always use energy - ATP
In the muscle stretch reflex, stretching of the biceps muscle leads to:
A contraction of the biceps and relaxation of the triceps
B relaxation of the biceps and contraction of the triceps
C contraction of the biceps and contraction of the triceps
D relaxation of the biceps and relaxation of the triceps
A contraction of the biceps and relaxation of the triceps
Due to differences in opposing forces, there is usually a
net _____ occurring at the arteriolar end of most capillaries coupled with
net ___ at the venous end.
absorption; filtration
filtration; absorption
filtration; absorption
During contraction of the sarcomere, which of the following changes in length?
A. I band shortens
B. A band shortens
C. Both A and I bands shorten
Upon muscle contraction, the A-bands do not change their length (1.85 micrometer in mammalian skeletal muscle), whereas the I-bands and the H-zone shorten
- What are the four factors that increase venous return to the heart?
Four factors can increase venous return (EDV):
- Skeletal muscle pump in which contraction of leg muscles surrounding the veins aids in returning blood to the heart.
- Respiratory pump in which deep breathing expands the chest and decreases the intra-thoracic cavity pressure.
- Sympathetic nervous system activation leads to greater constriction of the arterial vessels and large veins which moves the blood to the heart.
- Increase in blood volume as in blood doping.
What filaments insert into the M line of the sarcomere?
A. Thin filaments (actin)
B. Thick filaments (myosin)
C. Thick and thin filaments
Math foundation
- Define Natural numbers
- Define Integers
- Define fractions
- Define rational numbers
- Define rational number field
- Natural number NUM: A string of ones. Start with nothing make a stroke call it one. Add one to itself by adding another stroke and so on
- An INT is an ordered pair of natural numbers written m\n(m less n)
Integers include 0 and negatives of the natural numbers
- Fraction FRA: A fraction is an ordered pair (m,n) of natural numbers m/n
- Rational number RAT: A Rational number is an ordered pair of Integers a/b (bnot=0)
- (Rat, +, x) is a field [rational numbers, addition, multiplication] (most important field in mathematics)
When is PAO2 highest in the lung?
A end of expiration
B end of inspiration
C mid expiration
D mid inspiration
B end of inspiration
How does the autonomic nervous system get Ca++ into smooth muscle to activate the muscle?
MEMBRANE ACTIVATION
Contraction of smooth muscle, like skeletal muscle, is dependent on a rise of cytosolic Ca++ due to changes in the plasma membrane. However, smooth muscle does not have T tubules. Instead Ca++ enters from the ECF by diffusion through calcium channels in the plasma membrane. These Ca++ channels include: voltage-gated channels, ligand-gated channels and mechano-gated channels. The inputs that regulate contraction include:
Autonomic nervous system via voltage gated Ca++ channels.
Hormones via ligand-gated Ca++ channels.
Stretch via mechano-gated Ca++ channels.
At any one time, multiple inputs, some excitatory and others inhibitory, can be activated in a single cell. The net effect is dependent on the relative intensity of these inputs. Note that the intracellular Ca++ of smooth muscle can increase (or decrease) due to changes in the membrane potential from graded depolarization, hyperpolarization, or an action potential
How do hormones get Ca++ into smooth muscle to activate the muscle?
MEMBRANE ACTIVATION
Contraction of smooth muscle, like skeletal muscle, is dependent on a rise of cytosolic Ca++ due to changes in the plasma membrane. However, smooth muscle does not have T tubules. Instead Ca++ enters from the ECF by diffusion through calcium channels in the plasma membrane. These Ca++ channels include: voltage-gated channels, ligand-gated channels and mechano-gated channels. The inputs that regulate contraction include:
Autonomic nervous system via voltage gated Ca++ channels.
Hormones via ligand-gated Ca++ channels.
Stretch via mechano-gated Ca++ channels.
At any one time, multiple inputs, some excitatory and others inhibitory, can be activated in a single cell. The net effect is dependent on the relative intensity of these inputs. Note that the intracellular Ca++ of smooth muscle can increase (or decrease) due to changes in the membrane potential from graded depolarization, hyperpolarization, or an action potential
Nervous system
- When is the parasympathetic system mostly activated?
- When is the sympathetic system mostly activated?
- Give a car analogy for these two systems
Many organs are innervated by the parasympathetic and sympathetic nerves, or bundles of axons. In most cases this allows one system to activate the organ and the other system to inhibit it.
1.2. In general, the parasympathetic system is activated during periods of rest or digestion while the sympathetic system is most active during the fight or flight situations.
The sympathetic system prepares us for fighting by increasing the heart rate, releasing glucose from the liver, and dilating our pupils. In addition, the sympathetic system can divert blood from the skin and digestive system to the heart, brain and skeletal muscles.
- The sympathetic branch of the autonomic nervous system can be thought of as the gas pedal on a car while the parasympathetic branch is like the brake.
This dual control of systems that cause opposing actions allows for fine control of an organ’s activity and overall body homeostasis.
Which of the following types of muscles have sufficient numbers of gap junctions between fibers to propagate action potentials between cells?
A both cardiac muscle and single-unit smooth muscle
B cardiac muscle only
C multi-unit smooth muscle only
D both cardiac muscle and multi-unit smooth muscle
E single-unit smooth muscle only
A both cardiac muscle and single-unit smooth muscle
Muscle
Skeletal muscle fibers are classified by the speed of their myosin ATPase and preferred metabolism
- Name them
Skeletal muscle fibers are classified into one of three types distinguished by the speed of their myosin ATPase and preferred metabolism:
- *fast, glycolytic fibers** fatigue quickly
- *fast, oxidative, glycolytic fibers** resist fatigue
- *slow, oxidative fibers** resist fatigue
Fast fibers undergo cross-bridge cycling about 4 times faster than slow fibers. Oxidative fibers contain lots of mitochondria for aerobic metabolism during tasks that require endurance. Glycolytic fibers use only small amounts of oxygen and are larger in diameter than oxidative fibers. As a result of their larger diameter, each glycolytic fiber can produce more tension than an oxidative fiber. Most skeletal muscles include all three fiber types. However, each motor unit contains only a single type of muscle fiber. Motor units containing slow, oxidative fibers contain fewer fibers than motor units containing fast fibers.
Recruitment is the process of activating different types of muscle fibers within a fascicle in response to need. Recruitment starts with slow, oxidative fibers that do not provide a lot of force but can provide fine muscle control. If more tension is needed, fast-oxidative-glycolytic fibers can be recruited. Finally, fast, glycolytic fibers that fatigue rapidly increase tension the most dramatically are recruited.
Neuron
- What is convergence in neuron signalling?
- What is divergence in neuron signalling?
Neurons signal to one another through a specialized junction called a synapse. The synapse is where the electrical signal from one neuron (presynaptic neuron) is transmitted to another neuron (postsynaptic neuron).
Depending on the role of a particular neuron, it can
- receive signals from many presynaptic neurons (convergence) or it can
- send signals to many postsynaptic neurons (divergence).
The presynaptic neuron causes a graded potential to occur in the postsynaptic neuron. The graded potential can depolarize the postsynaptic membrane, which makes the potential closer to threshold, and is called an excitatory postsynaptic potential (Figure 26, synapses 1 and 2).
Alternatively, the graded potential can hyperpolarize the postsynaptic membrane, which makes the membrane potential farther from threshold, and is called an inhibitory postsynaptic potential (Figure 26, synapse 3). Since presynaptic neurons cause graded potentials in postsynaptic neurons, spatial and temporal summation of signals from multiple synapses can occur so the postsynaptic neuron can integrate informationNeuron
Neuron
- What is Saltatory conduction of an action potential?
- How does it work?
- Why is it used?
In the human body, axons can be quite long (from the spinal cord to the tip of the toe).
In order for an action potential to travel quickly along an axon that may be one meter long, some axons are myelinated.
Myelin is an insulator that is made up of many layers of specialized plasma membrane that is formed by Schwann cells in the peripheral nervous system and oligodendrocytes in the central nervous system.
The Schwann cells and oligodendrocytes lay the myelin along the axons with regularly spaced gaps called nodes of Ranvier.
The myelin speeds conduction along an axon by insulating it and preventing leaking of ions in the area around an action potential. This allows the effects of the action potential, or the change in membrane potential, to be detected further down the axon in the neighboring node where there is a concentration of ion channels.
In a myelinated axon, the action potential jumps from node to node allowing it to travel more quickly and more efficiently
SPINAL CORD ANATOMY
- Where do sensory signals come into the spinal cord?
- What do these neurons do to motor neurons in the spinal cord?
SPINAL CORD ANATOMY
The cell bodies of the neurons that innervate skeletal muscle of the body are found in the ventral horn of the spinal cord (Figure 37, blue).
The neurons that innervate the skeletal muscle of the head are in the brainstem.
In the body, sensory signals come into the spinal cord from the dorsal root ganglia, which contain the cell bodies of sensory neurons (Figure 37, red). These neurons can excite motor neurons in the spinal cord.
Motor neuron axons travel through tissues as nerves and synapse on skeletal muscle cells.
Excitation of motor neurons causes acetylcholine to be released at the neuromuscular junction causing contraction of the muscle. The muscle relaxes when the motor neuron is no longer excited
At the first half mile of a marathon run you would expect which of the following?
A PaCO2 to decrease but no change in PaO2.
B PaCO2 and PaO2 to show little or no change from resting values.
C PaCO2 to increase and PaO2 to decrease.
D PaCO2 and PaO2 to decrease markedly.
B PaCO2 and PaO2 to show little or no change from resting values.
Sex linked traits
Draw a Punnett square for sex linked traits - hemophilia
Who is the carrier?
Who is affected?
Mother is the carrier
Son is affected
Dihybrid cross
Show the dominant and recessive genes for a dihybrid cross
Show the Mendelian ratio of traits in the second generation
Figure 2 Dihybrid cross.
The phenotypes of two independent traits show a 9:3:3:1 (DD, Dr, rD, rr) ratio in the F2 generation.
In this example, coat color is indicated by B (brown, dominant) or b (white), while tail length is indicated by S (short, dominant) or s (long).
When parents are homozygous for each trait (SSbb and ssBB), their children in the F1 generation are heterozygous at both loci and only show the dominant phenotypes (SsbB).
If the children mate with each other, in the F2 generation all combinations of coat color and tail length occur:
9 are brown/short (purple boxes), 3 are white/short (pink boxes), 3 are brown/long (blue boxes) and 1 is white/long (green box).
Hearing
- How is sound transmitted to the cochlea?
Sound transmission
The outer ear, which consists of the pinna and external auditory canal, amplify and direct the sound to the middle ear (Figure 32).
The middle ear is an air filled cavity with three bones, the malleus, incus, and stapes.
The sound hits and deforms the tympanic membrane between the outer and middle ear (Figure 32).
The three bones of the middle ear respond to the deformation of the tympanic membrane and amplify the vibration to the oval window on the cochlea of the inner ear.
Because the oval window is much smaller than the tympanic membrane, the vibrations are amplified.
This is important because in the inner ear, fluid is used to transmit the sound
Neurons
- Draw the organisation of the efferent peripheral nervous system
(show paths, neurotransmitters and receptors)
The nervous system contains many types of neurotransmitters along with their respective receptors. There are two main types of synapses that are not only found in the central nervous system but also in the periphery.
In cholinergic synapses the presynaptic neuron releases acetylcholine as the neurotransmitter and it is received by one of two main types of receptors in the postsynaptic neuron or cell.
Skeletal muscle and brain express nicotinic receptors which are ion channels that are gated by acetylcholine.
In heart, smooth muscle and glands, muscarinic receptors bind acetylcholine which starts a signal transduction pathway that regulates ion channels.
Adrenergic synapses release either norepinephrine or epinephrine into the synaptic cleft.
The norepinephrine or epinephrine binds to one of two classes of receptors, alpha-adrenergic or beta-adrenergic receptors.
Both types of receptors use signal transduction to affect the postsynaptic cell which can be in the heart, smooth muscle, or a gland
Cardiac Performance
Consider the Pressure-Volume (PV) Loop below. The black PV loop (designated by ABCD) depicts the Left Ventricle of a normal heart.
- The red PV loop depicts the LV of a heart with: A. decreased systemic pressure (after load) B. increased systemic pressure (after load)
Answer 1: B. increased systemic pressure (after load)
Cardiac Performance
Consider the Pressure-Volume (PV) Loop below. The black PV loop (designated by ABCD) depicts the Left Ventricle of a normal heart.
- What occurs at D and H? A. AV valve closes B. aortic valve opens C. AV valve opens D. aortic valve closes
Answer 3: D. aortic valve closes
Living things taxonomy
Draw from common ancestor of all organisms - through humans
[mnemonic]
“King Phillip Came Over From Great Spain”
Kingdom Phylum Class Order Family Genus Species
Diagram then
Kingdoms - animals, plants
Phylum - Chordata (animals with backbone), etc
Class - mammalia, reptilia etc
Order - primates, bats etc
Family - hominidae (humans & great apes), baboons etc
Genus - homo, orangutan, etc
Species - homo sapiens, etc
SPINAL CORD ANATOMY
- The cell bodies of the neurons that innervate skeletal muscle of the body are found in the ??..??…?..?..??..??
SPINAL CORD ANATOMY
- The cell bodies of the neurons that innervate skeletal muscle of the body are found in the ventral horn of the spinal cord (Figure 37, blue).
The neurons that innervate the skeletal muscle of the head are in the brainstem.
In the body, sensory signals come into the spinal cord from the dorsal root ganglia, which contain the cell bodies of sensory neurons (Figure 37, red). These neurons can excite motor neurons in the spinal cord.
Motor neuron axons travel through tissues as nerves and synapse on skeletal muscle cells.
Excitation of motor neurons causes acetylcholine to be released at the neuromuscular junction causing contraction of the muscle. The muscle relaxes when the motor neuron is no longer excited
Neuron
- What is an action potential?
- An action potential is an electrical signal like graded potentials but they differ in several ways.
Action potentials are large changes in membrane potential that have a similar pattern of membrane potential change.
In this way, an action potential is an all-or-none phenomenon because either there is a large change in membrane potential if the stimulus was adequate or there is little change in membrane potential.
In addition, action potentials have the same intensity as they travel along a membrane – they do not diminish over distance.
Cardiac Performance
Consider the Pressure-Volume (PV) Loop below. The black PV loop (designated by ABCD) depicts the Left Ventricle of a normal heart.
- Are the stroke volumes (SV) for these two hearts equal? A. Yes, each is 60 mls B. No, red loop SV is 150 ml; black loop SV is 120 mls. C. No, red loop SV is 90 mls; black loop SV is 60 mls
Answer 4: A. Yes, each is 60 mls
Golgi Tendon Reflex.
- If the Golgi tendon organs of a muscle are stretched and stimulated, muscle ….?…. is inhibited through inhibition of the motor neuron leading to that muscle.
- This is because the afferent neuron activates an ….?…. neuron which is synapsing with the .…?…. neuron (Figure 40).
Golgi Tendon Reflex.
- If the Golgi tendon organs of a muscle are stretched and stimulated, muscle contraction is inhibited through inhibition of the motor neuron leading to that muscle.
- This is because the afferent neuron activates an inhibitory neuron which is synapsing with the motor neuron (Figure 40).
In addition, the opposing muscle is stimulated to contract through the interaction of an excitatory interneuron with the afferent neuron (Figure 40).
The Golgi tendon reflex acts to protect muscles and tendons from damage due to excessive tension. In addition, they may play a role in equalizing the load across different parts of a muscle.
