Biology 2

Question 1

Endocrinology

1. 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.
2. 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

Answer 1

1. 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

Question 2

Senses

1. How does the central nervous system, receiving signals from afferent receptors, know how intense a sensation is?

Answer 2

Frequency of action potentials.

Question 3

15. 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

Answer 3

E. unchanged
Well done!

Question 4

2. 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 4

Answer 2: C. increased metabolites in the IS surrounding the muscle

Question 5

Cell membranes - water transport

1. 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

Answer 5

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

Question 6

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

Answer 6

Yes

Question 7

When is PAO2 highest in the lung?

end of expiration

end of inspiration

mid expiration

mid inspiration

Answer 7

end of inspiration

Question 8

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.

Answer 8

B. functional residual capacity is greater than normal due to increased lung compliance.

Question 9

A decrease in blood pH will _________ the rate of breathing.

increase

decrease

not change

Answer 9

increase

Question 10

3. 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 10

Answer 3: B. Lower capillary hydrostatic pressure

Question 11

Neurons

1. How are signals integrated by a post synaptic neuron?

_{(text + diagram of three pre-synaptic neurons firing)}

Answer 11

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

Question 12

Neurons

1. What affects the speed of an action potential?

Answer 12

1. 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

Question 13

Muscle

1. What is excitation-contraction coupling?

Answer 13

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

Question 14

Bone joints

1. Describe the types of joints _{(how they connect, not articulation)}

Answer 14

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}

Question 15

Acid-base

1. What is the Henderson-Hasselbalch approximation used for?
2. Write the equation

Answer 15

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

padlet

derivation

Question 16

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

Answer 16

D 125/70

Question 17

Cardiac muscle

1. Describe the three steps in the ELECTRICAL – CONTRACTION (E-C) COUPLING in cardiac muscle

Answer 17

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).

1. Depolarization of the T tubule membrane opens the voltage gated Ca++ channels (dihydropyridine receptor), permitting the entry of a small amount of Ca++.
2. This Ca++ opens the Ca++ gated Ca++ channel (ryanodine receptor) on the sarcoplasmic reticulum (SR) thereby releasing a lot of Ca++ into the cytoplasm.
3. 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

Question 18

4. 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

Answer 18

E. A, B, C, and D
Well done!

Question 19

Two types of lower motor neurons

1. During muscle contraction what are coactivated?

Answer 19

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.

S_{tretching 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.}

Question 20

Cell membrane pumps

1. How do they move solutes? _{(in terms of concentration)}
2. What energy do pumps use - if any?

Answer 20

1. From [low] to [high]
2. Pumps always use energy - ATP

Question 21

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

Answer 21

A contraction of the biceps and relaxation of the triceps

Question 22

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

Answer 22

filtration; absorption

Question 23

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

Answer 23

A. I band shortens

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

Question 24

1. What are the four factors that increase venous return to the heart?

Answer 24

Four factors can increase venous return (EDV):

1. Skeletal muscle pump in which contraction of leg muscles surrounding the veins aids in returning blood to the heart.
2. Respiratory pump in which deep breathing expands the chest and decreases the intra-thoracic cavity pressure.
3. Sympathetic nervous system activation leads to greater constriction of the arterial vessels and large veins which moves the blood to the heart.
4. Increase in blood volume as in blood doping.

Question 25

Long bone structure 1. Draw

Answer 25

[image LINK](http://classes.midlandstech.edu/carterp/Courses/bio210/chap06/Slide3.JPG)

Question 26

What filaments insert into the M line of the sarcomere? A. Thin filaments (actin) B. Thick filaments (myosin) C. Thick and thin filaments

Answer 26

[B. Thick filaments (myosin)](http://padlet.com/davidofbuderim/coz0oorilmez)

Question 27

Math foundation 1. Define Natural numbers 2. Define Integers 3. Define fractions 4. Define rational numbers 5. Define rational number field

Answer 27

1. 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} 2. An INT is an ordered pair of natural numbers written m\n(m less n) _{Integers include 0 and negatives of the natural numbers} 3. Fraction FRA: A fraction is an ordered pair (m,n) of natural numbers m/n 4. Rational number RAT: A Rational number is an ordered pair of Integers a/b (b_not=0) 5. (Rat, +, x) is a field _{[rational numbers, addition, multiplication] (most important field in mathematics)}

Question 28

When is PAO2 highest in the lung? A end of expiration B end of inspiration C mid expiration D mid inspiration

Answer 28

B end of inspiration

Question 29

How does the autonomic nervous system get Ca++ into smooth muscle to activate the muscle?

Answer 29

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

Question 30

How do **hormones** get Ca++ into smooth muscle to activate the muscle?

Answer 30

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

Question 31

Nervous system 1. When is the parasympathetic system mostly activated? 2. When is the sympathetic system mostly activated? 3. Give a car analogy for these two systems

Answer 31

_{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. 3. 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.}

Question 32

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

Answer 32

A both cardiac muscle and single-unit smooth muscle

Question 33

Draw skeletal muscle functional view | (sarcomere)

Answer 33

[Image LINK](http://www.nature.com/nrm/journal/v12/n6/images/nrm3118-f1.jpg) IZ MA

Question 34

Muscle Skeletal muscle fibers are classified by the speed of their myosin ATPase and preferred metabolism 1. Name them

Answer 34

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.

Question 35

Neuron 1. What is convergence in neuron signalling? 2. What is divergence in neuron signalling?

Answer 35

_{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 1. receive signals from many presynaptic neurons **(convergence)** or it can 2. 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}

Question 36

Neuron 1. What is Saltatory conduction of an action potential? 2. How does it work? 3. Why is it used?

Answer 36

_{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**

Question 37

SPINAL CORD ANATOMY 1. Where do sensory signals come into the spinal cord? 2. What do these neurons do to motor neurons in the spinal cord?

Answer 37

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

Question 38

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.

Answer 38

B PaCO2 and PaO2 to show little or no change from resting values.

Question 39

Consider the following pulmonary function test data from a patient with pulmonary fibrosis in answering the question below. Predicted Observed %Predicted Vital Capacity (Liters) 4.1 1.4 34 Expiratory Reserve Volume (Liters) 1.4 0.2 14 Residual Lung Volume (Liters) 2.3 1.2 52 Total Lung Capacity (Liters) 6.4 2.6 41 Tidal Volume (Liters) 0.6 Anatomic Dead Space (Liters) 0.14 For this patient, the functional residual capacity (FRC) would be closest to: A. 2.4 Liters B. 1.4 Liters C. 2.8 Liters D. 1.2 Liters

Answer 39

B. 1.4 Liters

Question 40

When a baroreceptor activity decreases due to a decrease in blood pressure: A sympathetic activity increases. B cardiac output increases. C peripheral resistance decreases. D A and B E B and C

Answer 40

D A and B

Question 41

Cell transporters 1. What solutes can a transporter move across the cell membrane?

Answer 41

The transporters are specific to a solute (or several). ie they are NOT general purpose transporters

Question 42

Two types of lower motor neurons Stretching of the intrafusal fibers in the muscle spindle is sensed by stretch receptors and sent via afferent sensory neurons to the spinal cord. 1. This allows for monitoring of the ......???..... of the muscle which helps control muscle tone.

Answer 42

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.

Question 43

Muscle Which of the following occurs during muscle contraction? A. the A bands get shorter B. the I bands get shorter C. the Z lines get closer together D. the Z lines get farther apart A and C B and C

Answer 43

B and C

Question 44

Homeostasis 1. What is homeostasis in the human body? 2. Why is it important? 3. What is the main area of the body that organs act on to maintain homeostasis?

Answer 44

1. The body gets lots of input perturbing the current state. Organs act to get back to the desired conditions. 2. The cells require their surroundings to be within quite narrow bands in order to function 3. ECF (Extra cellular fluid) - maintaining their constiruents relatively constant

Question 45

Diseases affecting striated muscle cells are uncommon but are devastating and often lethal because normal striated muscle function is required for: A. heart beat B. swallowing C. breathing D. B and C E. A, B and C

Answer 45

E. A, B and C A. Cardiac muscle is a striated fiber containing the same arrangements of contractile filaments as skeletal muscle _{Smooth muscle is an involuntary, non-striated type associated with blood vessels and visceral organs Smooth muscle regulates air flow in lungs}

Question 46

Sex linked traits Draw a Punnett square for sex linked traits - hemophilia Who is the carrier? Who is affected?

Answer 46

Mother is the carrier Son is affected

Question 47

1. How does Ca++ enter smooth muscle to activate the membrane?

Answer 47

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

Question 48

Alveoli are less compliant at: Low lung volume High lung volume Functional residual capacity (FRC)

Answer 48

High lung volume

Question 49

17. The main site of variable resistance in the systemic circulation, contributing more than 60% of the total resistance are: E. veins A. muscular arteries B. elastic arteries D. venules C. arterioles

Answer 49

C. arterioles Well done!

Question 50

Dihybrid cross Show the dominant and recessive genes for a dihybrid cross Show the Mendelian ratio of traits in the second generation

Answer 50

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).

Question 51

Hearing 1. How is sound transmitted to the cochlea?

Answer 51

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

Question 52

Cardiac muscle 1. In cardiac muscle the action potential activates the C++ gates in the ???

Answer 52

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

Question 53

Fused tetanus can occur in normal skeletal muscle when there is: A. delayed efflux of calcium through the ryanodine receptor B. a large graded potential (end plate potential) generated at the neuro-muscular junction. C. a temporal summation of individual contractions leading to maximal tension. D. an increase in the activity of the T tubule CaATPase

Answer 53

[C. a temporal summation of individual contractions leading to maximal tension.](http://padlet.com/davidofbuderim/coz0oorilmez)

Question 54

Predict the effect of aging (increased afterload) on baroreceptor activity. resets to higher set point resets to lower set point activated chronically inhibited chronically remains unchanged

Answer 54

resets to higher set point

Question 55

Osmosis - Osmolarity 1. Define osmolarity and compare with molarity 2. eg 1M NaCl

Answer 55

1. Osmolarity = **particles**/L considers ALL molecules Molarity = mol/L 2. 1M NaCl = 2 OsM NaCl because it is Na⁺ Cl^- ions in solution

Question 56

How are myocardial contractile cells linked mechanically? and electrically?

Answer 56

MYOCARDIAL CONTRACTILE CELLS are tightly linked to one another by **intercalated discs, specialized adhesive junctions, which ensure transmission of force** from one myocardial cell to an adjacent cell. The cells also contain **gap junctions that facilitate transmission of electrical impulses** from cell to cell. Myocardial contractile cells have a resting membrane potential of approximately -85 millivolts (mV). Depolarization occurs when the permeability to sodium increases, and sodium flows into the cell (Phase 0, Figure 57). As the membrane potential reaches about +20 mV, the voltage gated sodium channels inactivate. The muscle cell begins to repolarize as K+ leaves the cell through open voltage gated K+ channels (Phase 1). At this membrane potential, voltage gated Ca++ channels open causing the action potential to flatten as the K+ efflux balances the Ca++ influx. The plateau (Phase 2) ends when Ca ++ channels close and K+ efflux exceeds Ca++ influx. In Phase 3, K+ efflux repolarizes the muscle cell. The resting membrane potential is maintained by the activity of the Na-K ATPase (Phase 4)

Question 57

Hydrophobic and hydrophillic molecules Explain and characterise

Answer 57

A **hydrophilic** molecule or portion of a molecule is one that is typically **charge-polarized** and capable of **hydrogen bonding**, enabling it to dissolve more readily in water than in oil or other hydrophobic solvents. _{Hydrophobicity is the physical property of a molecule (known as a hydrophobe) that is seemingly repelled from a mass of water.[1] (Strictly speaking, there is no repulsive force involved; it is an absence of attraction.)} **Hydrophobic** molecules tend to be **non-polar** and, thus, prefer other neutral molecules and non-polar solvents. Hydrophobic molecules in water often cluster together, forming micelles. Water on hydrophobic surfaces will exhibit a high contact angle. _{Examples of hydrophobic molecules include the alkanes, oils, fats, and greasy substances in general. Hydrophobic materials are used for oil removal from water, the management of oil spills, and chemical separation processes to remove non-polar substances from polar compounds}

Question 58

Cardiac muscle 1. What is the absolute refractory period of cardiac muscle? 2. How long does the action potential last? 3. How long is a single contraction? 4. What are the implications for tetanus of the heart muscle?

Answer 58

[REFRACTORY PERIOD AND ABSENCE OF TETANUS](http://padlet.com/davidofbuderim/djz4ork23k1n) Absolute refractory period of the cardiac muscle action potential refers to the time interval when the voltage gated sodium channels are inactivated. **The absolute refractory period lasts ~180 msec.** **The action potential lasts 200-220 msec.** **A single contraction is 250 msec.** _{Recall that these voltage gated Na+ channels must undergo a conformational change from an “inactivated” state to a “closed” state before they can reopen and initiate another action potential. As a consequence of phase 2, the voltage gated Na+ channels remain “inactivated” for an extended period of time and do not “close” until repolarization in phase 3 (~180 msec). No amount of stimulus can cause an action potential during the absolute refractory period.} An important point regarding the refractory period is that contractions cannot sum and therefore **there is no fused tetanus (summed contractions).** Fused tetanus in the heart would lead to death as it would prevent the rhythmic pumping of blood.

Question 59

In a cell, if the equilibrium potential for Na+ is +50 mV and the equilibrium potential for K+ is -50 mV, what is the membrane potential if the membrane is equally permeable to Na+ and K+? +50 mV +25 mV 0 mV -25 mV -50 mV

Answer 59

0 mV

Question 60

In the eye, **relaxation** of the ciliary muscles encircling the lens will cause the lens to: become more rounded flatten ciliary muscles do not affect lens shape

Answer 60

flatten

Question 61

What sort of contractions can smooth muscle perform?

Answer 61

MYOSIN ATPase has a slow rate of hydrolysis. It hydrolyzes ATP at about 10% of the rate observed in skeletal muscle. Consequently smooth muscle produces **slow, sustained contractions using only 10%** of the ATP that skeletal muscle would require for the same work

Question 62

Neurons 1. Draw the organisation of the efferent peripheral nervous system _{(show paths, neurotransmitters and receptors)}

Answer 62

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

Question 63

genotype = phenotype = dominant trait - expressed in ... A/a recessive trait - expressed in ...A/a homozygous = A/a heterozygous = A/a allele =

Answer 63

genotype = genetic makeup phenotype = expression of a trait dominant trait - expressed in AA Aa aA recessive trait - expressed in aa homozygous = individual having AA or aa heterozygous = individual having aA or Aa allele = A or a *An allele is a variant form of a gene. Some genes have a variety of different forms, which are located at the same position, or genetic locus, on a chromosome. Humans are called diploid organisms because they have two alleles at each genetic locus, with one allele inherited from each parent.*

Question 64

Cardiac Performance Consider the Pressure-Volume (PV) Loop below. The black PV loop (designated by ABCD) depicts the Left Ventricle of a normal heart. 1. The red PV loop depicts the LV of a heart with: A. decreased systemic pressure (after load) B. increased systemic pressure (after load)

Answer 64

Answer 1: B. increased systemic pressure (after load)

Question 65

Cell membrane secondary active transport 1. Give a general definition of secondary active transport mechanism 2. Describe how glucose and Na+ are transported across a cell from the intestines into the blood

Answer 65

1. secondary active transport couples the activity of a co-transporter with a pump 2. They enter the cell together via a symporter the glucose leaves the cell via diffusion the Na+ leaves via an active pump (using ATP) and K+ enters [image LINK](https://classconnection.s3.amazonaws.com/27/flashcards/2060027/jpg/glucose_transport_epithelial_cells1349801502218.jpg)

Question 66

A decrease in blood pH will _______ the rate of breathing. A. decrease B. increase C. not change

Answer 66

B. increase

Question 67

Cardiac Performance Consider the Pressure-Volume (PV) Loop below. The black PV loop (designated by ABCD) depicts the Left Ventricle of a normal heart. 3. What occurs at D and H? A. AV valve closes B. aortic valve opens C. AV valve opens D. aortic valve closes

Answer 67

Answer 3: D. aortic valve closes

Question 68

The dark (A band) region of skeletal muscle contains: A. Thin filament (actin) only B. Thick filament (myosin) C. Myosin-actin overlap region only

Answer 68

[B. Thick filament (myosin)](http://padlet.com/davidofbuderim/coz0oorilmez)

Question 69

What filaments insert into the Z line of the sarcomere? A. Thin filament (actin) B. Thick filament (myosin) C. Thick and thin filaments

Answer 69

[A. Thin filament (actin)](http://padlet.com/davidofbuderim/coz0oorilmez)

Question 70

The Circulatory System 1. If blood flow to an arm is obstructed for more than 30 seconds while taking a blood pressure, then release of the cuf will be followed by a temporary rise in blood flow and a return to resting levels. The higher blood flow is caused by \_\_\_. A. an increase in total peripheral resistance (TPR). B. a temporary increase in mean arterial pressure. C. local vasodilation due to the build up of metabolites. D. shifting blood flow from other organs.

Answer 70

Answer 1: C. local vasodilation due to the build up of metabolites.

Question 71

n the last half mile of a marathon run, you would expect which of the following? A PaCO2 to increase B PaCO2 to decrease C PaCO2 to remain 40 mmHg

Answer 71

B PaCO2 to decrease

Question 72

Nancy arrived at the emergency room in a coma. You suspect a drug overdose which has depressed her rate and depth of breathing. As a consequence you expect her PaCO2 level to be: increased decreased normal

Answer 72

increased

Question 73

Living things taxonomy Draw from common ancestor of all organisms - through humans [mnemonic]

Answer 73

"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

Question 74

SPINAL CORD ANATOMY 1. The cell bodies of the neurons that innervate skeletal muscle of the body are found in the **??..??...?..?..??..??**

Answer 74

SPINAL CORD ANATOMY 1. 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}

Question 75

After a skeletal muscle fiber is treated with a membrane permeable drug that speeds up the action of the SR Ca+2-ATPase, how would contraction differ after multiple and frequent action potentials? A the maximal tension would be increased compared to an untreated fiber B fused tetanus would be reached in the same amount of time as an untreated fiber C fused tetanus would be reached later than an untreated fiber D fused tetanus would be reached sooner than an untreated fiber

Answer 75

C fused tetanus would be reached later than an untreated fiber the SR Ca+2-ATPase pumps Ca++ back into the Sarcoplasmic Reticulum

Question 76

The impulse from the pacemaker cells flows in a unidirectional manner throughout the heart via specialized conducting tissue (Figure 55) and into the heart muscle. 1. Draw and identify the tissues and the order

Answer 76

[padlet-electrical conduction in the heart](http://padlet.com/davidofbuderim/gpf807lxm9f9)

Question 77

Balance 1. How do the Ololith organs in the inner ear work?

Answer 77

Otolith organs The otolith organs contain sheets of hair cells that have **calcium carbonate crystals**, called otoliths, embedded in gel that surrounds the stereocilia of the hair cells. Since the otoliths are **heavier than the fluid** around the hair cells, they remain stationary and pull on the stereocilia during linear movements. _{The utricle contains hair cells that point straight up in a standing postion and respond to horizontal linear acceleration. The saccule contains hair cells that are oriented at a 90 degree angle compared to those of the utricle (Figure 35). This allows them to detect up and down motions}

Question 78

What is the electrical event on the ECG that precedes ventricular diastole?

Answer 78

T wave

Question 79

Draw a structure of human skin diagram

Answer 79

[image LINK](http://static5.depositphotos.com/1006480/507/v/950/depositphotos_5078000-Diagram-of-the-Human-Skin.jpg)

Question 80

An increase in tissue PCO2 will cause vasoconstriction in: A arterioles that perfuse the lung alveoli B arterioles that perfuse skeletal muscle C arterioles perfuse lung alveoli and skeletal muscle D veins only

Answer 80

A arterioles that perfuse the lung alveoli

Question 81

16. Abnormally slow conduction through the ventricles would change the \_\_\_\_\_\_\_\_in an EKG. B. T wave A. P wave C. QRS complex D. B and C

Answer 81

D. B and C Well done!

Question 82

Neuron 1. What is an action potential?

Answer 82

1. 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**.

Question 83

Osmosis - Osmolarity 1. In the body what is the osmolarity? 2. What is an equal osmolarity called? 3. What is a lower osmolarity called? 4. What is a higher osmolarity called?

Answer 83

1. 300 mOsM (milli Osmolars) 2. **iso**smotic 3. **hypo**osmotic 4. **hyper**osmotic

Question 84

Cardiac Performance Consider the Pressure-Volume (PV) Loop below. The black PV loop (designated by ABCD) depicts the Left Ventricle of a normal heart. 4. 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 84

Answer 4: A. Yes, each is 60 mls

Question 85

Muscle _{In muscle Thick and thin filaments are organized into a series of repeating functional units} 1. What are the units called? 2. Draw one (_{showing zones and bands})

Answer 85

[padlet](http://padlet.com/davidofbuderim/coz0oorilmez)

Question 86

The Golgi tendon organ fires action potentials most frequently when its associated muscle is in which state? relaxed stretched contracted

Answer 86

contracted

Question 87

What is the I band of the sarcomere? A. Thin filament (actin) only B. Thick filament (myosin) only C. Myosin-actin overlap

Answer 87

[A. Thin filament (actin) only](http://padlet.com/davidofbuderim/coz0oorilmez)

Question 88

Muscle tissue 1. Name the types of muscle tissue

Answer 88

1. Skeletal, Cardiac, smooth

Question 89

Golgi Tendon Reflex. 1. 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. 2. This is because the afferent neuron activates an **....?....** neuron which is synapsing with the .**...?...**. neuron (Figure 40).

Answer 89

Golgi Tendon Reflex. 1. 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. 2. 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.}

Question 90

If blood pressure doubled at the same time that peripheral resistance doubled, the blood flow through a vessel would be: doubled halved 16 times greater unchanged

Answer 90

unchanged

Question 91

Muscle 1. What contractile proteins do all three muscle types contain?

Answer 91

All three types of muscle contain the contractile proteins, **myosin and actin,** contract to generate force, and share 3 common principles: Sliding filament mechanism in which myosin filaments bind to and pull actin filaments as a basis for shortening. Regulation of contractile proteins by calcium ions. Changes in membrane potential lead to a rise in intracellular calcium resulting in contraction (E-C coupling)

Question 92

18. When a person rises quickly from a prone position: D. heart rate decreases A. the carotid baroreceptors become more active B. venous return is unchanged C. reflex vasoconstriction of the peripheral blood vessels occurs

Answer 92

C. reflex vasoconstriction of the peripheral blood vessels occurs Well done!

Question 93

Which of the following conditions leads to decreased lung compliance? A Decreased production of surfactant B Increased fibrosis C Increased fluid in the interstitial space surrounding the alveoli (edema) D A, B and C

Answer 93

D A, B and C

Question 94

John donated 1 liter of blood to the Red Cross. In response, the baroreceptors ____ their firing. increased decreased no effect

Answer 94

decreased

Question 95

Which of the following promote edema formation? A decreased blood protein concentration B lymphatic blockage C venous blockage (clot) D A and C E A, B, and C

Answer 95

E A, B, and C

Question 96

Nervous system 1. Name the main cell types in the nervous system

Answer 96

1. Neurons Glial cells (support neurons)