exam 2 human physiology

In the case of a hemorrhage the blood volume decreases, which leads to a decrease in stroke volume. What will happen to cardiac output?

Decreased cardiac output

For most receptor pathways a ____ soluble molecule will bind to the surface receptor, whereas a _____ soluble molecule will bind to a receptor on the inside of a cell

Water / Lipid

In chemical messenger pathways, the molecule that initially binds to the receptor, usually on the outside of the cell is known as the?

First messenger

In a G-coupled receptor (GPR), the G protein is a combination of three subunits. Which subunit leaves the other subunits as it gains an affinity for GTP

Alpha

In a cAMP associated G-coupled receptor pathway, the G protein subunit mentioned in the previous question eventually activates a special protein embedded in the membrane that will catalyze the conversion of ATP into cAMP. What is the protein?

Adenylyl cyclase

When comparing lipid soluble and water soluble messengers, which will have a slower but more sustained response?

Lipid soluble messengers

A second messenger is a substance that

is generated in the cytoplasm as a result of receptor activation by the first messenger / is brought into the cell as a response to the first messenger / helps relay the signal transduction message to lead to cell's response

Caffeine works by inhibiting cAMP phosphodiesterase. What effect will this have on cells?

Increased activation due to increased cAMP concentrations

In cross bridge cycling for a muscle cell, __1__ ions are first released from the __2___. These ions bind to the __3__, which cause them to pull up on ___4___ on the thin filament, also known as ___5___. This opens up binding sites for the thick filament, otherwise known as ___6___. This allows an ___7___ thick filament to bind to the thin filament. From here, the thick filament ___8___, initiating the sliding filament mechanism while also releasing ___9___. ___10___ then binds to the thick filament, allowing the two filaments to ___11___. ___12___ of ATP by the thick filament reenergizes the cross bridge so that the process can start again.

1. Calcium / 2. Smooth ER / 3. Troponin / 4. Tropomyosin / 5. Actin / 6. Myosin / 7. Energized / 8. Flexes / 9. ADP / 10. ATP / 11. Detach / 12. hydrolysis

What is the definition of a motor unit

A single motor neuron plus all the muscle fibers it innervates

Anti-histamines work by binding to the same receptor that histamine would normally bind to. This means that anti-histamines and histamines share the same ____ for the protein

Specificity

Which of the following are ways in which binding of a chemical messenger with a cell's receptor can bring about a cellular response?

Opening or closing of specific ionic channels in the plasma membrane / activation of an intracellular second-messenger system / promoting or inhibiting intracellular enzymes / activating or inhibiting intracellular enzymes

Heroin is an opioid agonist. What would you expect to see for the number of opioid receptors in an individual that is addicted to heroin

A decrease in number due to down-regulation

Naloxone (narcan) is a high affinity antagonist to the opioid receptor, the same receptor to which heroin is an agonist. If both heroin and naloxone were in the bloodstream, what would the user experience?

A decrease in the effects of heroin

Amplification during a second-messenger cascade is beneficial because amplification....

allows small amounts of hormones to produce large responses in target cells

A myelin sheath is?

An area of the axon covered in layers of membrane that is impermeable to ion movement

Which is FALSE about neurons?

A neuron receives information on its axons and delivers it to other neurons through it dendrites

Which is TRUE about typical, resting neurons?

The permeability of the plasma membrane to potassium ions is much greater than its permeability to sodium ions, causing the RMP to be closer to the equilibrium potential for potassium.

An action potential does not re-stimulate the adjacent membrane that was previously depolarized because

That area of the membrane is in the absolute refractory period

what is the best description of a tetanic contraction in a skeletal muscle cell

Multiple action potentials in the motor neuron cause a sustained contraction

An action potential travels down the axon where it reaches ___1___ channels in the axon terminal. These channels are triggered when the membrane potential inside the cell becomes more ___2___ As these ions rush in, they attach to __3__. proteins. These proteins allow vesicles that carry

___4____ to combine with the plasma membrane of the neuron, thereby releasing neurotransmitter into the synaptic cleft. The secreted substances then bind to ____5___ gated ion channels, which mostly allow ___6___ ions to move into the cell. This then initiates a wave of electrical current across the muscle fiber. The action potential reaches a ___7.___ where it is able to travel deep into the muscle fiber. DHP receptors sense the action potential and pull on _____8____ receptors that are on the surface of the ____9____ These receptors are channels that allow ____10____ ions to flow out of the organelle into the cytosol

1. Ca (calcium) / 2. positive / 3. Snare / 4. neurotransmitter / 5. Ligand / 6. Na (sodium) / 7. Transverse tubule / 8. Ryanodine / 9. Sarcoplasmic Reticulum / 10. Ca (calcium)

Which is TRUE about the Na/K ATPase pump in neurons?

it maintains a concentration gradient for K such that diffusion forces favor movement of K out of the cell

Which of the following statements regarding action potentials generated in a neuronal membrane is FALSE

Action potentials travel in both directions along the axon

High extracellular concentration; involved in a typical action potential

Na - Sodium

Binds to calsequestrin in the Smooth ER

Ca - Calcium

Activated by a G proteins and adenylyl cyclase

cAMP

High concentration within the sarcoplasmic reticulum

Ca - Calcium

High intracellular cytosol concentration; involved in repolarization

K - potassium

Synthesized from guanosine triphosphate in a reaction catalyzed by guanylyl cyclase

cGMP

Neuronal axons typically have abundant

voltage-gated channels for Na that open in response to depolarization in a positive feedback loop

A motor neuron needs to innervate muscle fibers at a very fast rate. What characteristic will give the neuron the ability to conduct a signal the fastest?

Large diameter

The receptor itself functions as an enzyme

receptor tyrosine kinase

Cytoplasmic kinase that interacts with a receptor

Janus Kinase

Receptor that has a 3-subunit protein associated with it

G-protein coupled receptor

Channel that opens in response to an action potential

Voltage-gated ion channel

Channel that opens in response to a chemical messenger

Ligand-gated ion channel

How is the strength of a stimulus encoded by neurons

By the frequency of action potentials

which of the neuron types has its cell body inside the central nervous system

Interneuron / efferent neuron

Which of the neuron types sends messages away from the stimulus

afferent neuron

which of the neuron types is the most abundant

interneuron

which of the neuron types can conduct an action potential

Interneuron / afferent neuron / efferent neuron

which of the neuron types lies entirely within the central nervous system

interneuron

in response to a hemorrhage, the body will autotransfuse and take fluid from elsewhere in the body. From where is the body able to pull extra fluid

The Interstitium / interstitial fluid

In an individual that is dehydrated, their hematocrit will usually go up, such that they have "thick" blood. What effect will this have on flow rate

A decrease in flow rate

in the excitation of the heart, the signal stops at the AV node for a short delay. what is the consequence of this delay

it allows the atria to fill up the ventricles fully before contracting

Cardiac nodal cell membrane potentials function as a(n) ____1___ potential. These types of membrane potentials occur when ___2____ depolarization occurs in the membrane after repolarization. In the nodalvcell, this depolarization is caused by ___3____ sodium channels that open when the membrane is repolarized. As depolarization occurs, the ___4___ calcium channels open, which help bring the membrane potential to threshold. From there, L-type ___5___ channels open, causing depolarization of the membrane. ____6___ channels then fully open to allow for repolarization

1. pacemaker / 2. Gradual / 3. F-type / 4. T-type / 5. calcium / 6. potassium

At rest, the ___1___ maintains the ion concentrations on both sides of the neuronal membrane. To generate an action-potential, ___2____ -gated ____3____ ion channels are opened, leading to an influx of those ions through the neuron membrane. As these channels are opened, the membrane ____4_____ When an ____5____ charge is reached inside the cell, the "ball and chain" portion of a(n) ____6___ ion channel inactivates that ion channel. At this point, the slower ____7____ ion channels finally open, leading to a(n) efflux of those ions across the cell membrane. The cell membrane ____8____ Once this state of charge on the membrane is reached, the ion channels

1. Sodium/Potassium. pump / 2. voltage / 3. Na (sodium) / 4. depolarizes / 5. positive / 6. Na (sodium) / 7. K (Potassium) / 8. repolarizes

An action potential is able to travel quickly through a cardiac muscle cell due to the presence of

Gap junctions within the intercalated discs

What occurs during isovolumetric ventricular contraction

No blood enters or leaves the ventricles

Which is a TRUE statement about smooth muscle

Smooth muscle does not use troponin-tropomyosin to regulate cross-bridge activity.

Rigor mortis (stiffness of the dead body) is caused by

Lack of ATP

Which of the following changes would most increase the resistance to blood flow in a blood vessel

halving the diameter of the vessel, making it smaller

The plateau of the action potential in cardiac ventricular cells results from the opening of voltage-gated long-lasting _______channels in the plasma membrane of the cell

Ca - calcium

The plateau mentioned in the previous question regarding the action potential in cardiac muscle cells leads to the prevention of what activity by the heart

Tetanic contraction

Visual signals travel on myelinated axons. While most pain signals travel on unmyelinated axons. Theoretically, if you get a paper cut, will you see the cut happen or feel the pain first

you will experience the visual sensation before the pain sensation

In the first few seconds of skeletal muscle contraction, what is the main mechanism by which ATP is replenished after the initial stores are depleted

energy and phosphate are transferred from creatine phosphate to ADP

In the clotting system, activated platelets will release chemicals that bring in more platelets, which in turn will release more chemicals to draw in more platelets. This is an example

Positive feedback

Which of the following is NOT true about endothelial cells of the cardiovascular system

They are only found in the capillaries

any situation where a decrease in blood flow to an organ or tissue leads to damage is called

shock

Blood control into the capillaries is controlled by the ____1___. At the arterial end of the capillaries, ____2____ pressure inside the capillary is higher, and this will favor _____3____. At the venous end, ____4____ pressure is higher from the interstitial fluid, and this will favor ____5____. This pressure is typically constant because of the presence of ____6____ in relatively stable concentration throughout the body. These biomolecules cannot pass through the ____7____ of the capillaries due to their size. As blood travels through the capillaries, it will ____8____ due to the cross sectional area of the capillaries

1. arteriole - arterioles / 2. Hydrostatic / 3. Filtration / 4. Osmotic - Oncotic / 5. Absorption / 6. Protein / 7. Intercellular cleft / 8. Slow down