Bio 161 Exam 2

Which part of the brain is not functioning correctly if an individual cannot learn new facts and retain them?

hippocampus

Where is the thymus gland located

in the chest

Which one of the following is entirely located within the CNS

interneuron

Neurotransmitters transmit_____ between_____ from neurons to glands from neurons to organs, and from neurons to muscles

signals, neurons

Which of the following is a benefit of using chemical signals rather than electrical signals to send messages to the next neuron?

Electrical signals are too weak to cross the synaptic cleft, Multiple neurotransmitters are able to be released at once, increasing the range of responses generated, the distance between neurons is too far for an electrical signal to travel

Thus, the Z line moves inward and the ___ nearly disappears

H zone

Actin filaments slide past myosin filaments, causing the ____ to shorten

I band

Place the events in the transmission of an action potential in the correct order: 1. An action potential begins in the receiving neuron. 2. Neurotransmitters are released into the synaptic cleft. 3. An action potential arrives at an axon terminal. 4. Calcium ions enter the axon terminal. 5. Sodium ions diffuse into the receiving neuron. 6. Synaptic vesicles fuse with the plasma membrane. 7. Neurotransmitter molecules bind to the membrane of the receiving neuron

3,4,6,2,7,5,1

During one cycle, the sodium-potassium pump binds and moves

3Na+ and 2K+

what supplies the energy for muscle contraction

ATP

Energy is released when

ATP is broken down into ADP and phosphate

There are more than 100 known or suspected neurotransmitters.____ and noreprinephrine are active in the PNS and the CNS

Acetylcholine

What does troponin bind to, and what happens when it binds?

Ca2+; tropomyosin shifts

Interneurons

Lie entirely within the CNS, can receive input from sensory neurons and other interneurons, sum up information received from all other neurons, and communicate with motor neurons

Acetylcholine has which effect on the postsynaptic neuron?

Ligand-gated sodium ion channels open and sodium diffuses in

During depolarization which of the following statements about voltage-gated ion channel is true

Na+ gates open before K+ gates

During depolarization, which of the following statements about voltage-gated ion channels is true?

Na+ gates open before K+ gates

___ is involved in sleep, emotions, and perception

Serotonin

Motor Neurons

Take messages away from the CNS to an effector, communicate with effectors that carry out responses to environmental changes

What do smooth, cardiac, and skeletal muscles all have in common?

The cells of these muscles are all called muscle fibers

When the nerve signal reaches the axon terminal, what happens next?

The synaptic vesicles release neurotransmitter

Once neurotransmitters flow into the synaptic cleft between two neurons

They bind to receptor proteins on the surface of the postsynaptic neuron, they start a chain of events that results in a new action potential being generated within the postsynaptic neuron, they cause receptors to release sodium ions into the postsynaptic neuron

Several of the structures in the muscle cell are given special names. For example, the cytoplasm of a muscle fiber is called the sarcoplasm. Which of the following is truly a unique structure to muscle cells (not just a renamed one)?

Transverse (T) system

During contraction of a muscle, calcium ions bind to the

Troponin molecule

The gap where there is no myelin sheath around a nerve fiber is called a node of Ranvier.

True

the amount of ATP that normally exists in a muscle cell lasts for ____ during strenuous exercise

a few seconds

Muscle contraction is caused by

actin filaments sliding past myosin filaments

Muscle contraction can be studies using isolated, single muscle fibers. As opposed to a whole muscle, a single muscle fiber shoes____ contraction

all-or-none

The bond between the actin and myosin head is broken when

an ATP molecule binds to the myosin head

The actions of the____pituitary are influenced by releasing and inhibiting hormones produced by the hypothalamus. These either stimulate or inhibit the secretion of hormones by the anterior pituitary

anterior

the hypothalamus regulates the internal environment by communicating with the___ serving as a link between the nervous and endocrine systems

automatic nervous system

Why is the pancreas both an endocrine and an exocrine gland?

because it produces at least 1 hormone that is delivered through a duct and 1 that is delivered to the bloodstream

The hypothalamus also helps to regulate___

body temperature

what is the source of energy used to power the sodium-potassium pump?

breakdown of ATP

Skeletal muscle contraction allows the body to move, remain upright, and produce heat as ATP is ____

broken down

Most of the ATP generated by a muscle cell from ____, which uses either glucose or ____ to produce ATP. A muscle-specific molecule called ____ helps provide oxygen for this process

cellular respiration, fatty acids, myoglobin

The speediest way for muscle cells to make ATP is by breaking down ____, which occurs in the midst of the sliding filaments

creatine phosphate

How is alcohol classified?

depressant

The glandular secretions of the pituitary gland are.___ controlled by the hypothalamus. Through the anterior pituitary, the hypothalamus also___ controls the secretions of the thyroid, adrenal cortex, and gonads

directly, indirectly

Within a neuron, information is transmitted down the length of a single axon through

electrical signals called action potentials

which of the following is produced by the adrenal gland

epinephrine, norepinephrine, glucocorticoids, mineralocorticoids

The cells of the nervous tissue are all neurons, or cells that transmit nerve impulses.

false

The voltage-gated potassium channels close before the membrane potential is brought back to its resting level.

false

the binding of ATP allows the muscle filaments to slide past one another

false the binding of ATP allows the bond between actin and the myosin head to break

There are 3 ways that muscles can obtain new ATP. 2 methods, ____ and creatine phosphate breakdown, are anaerobic and are therefore available even when oxygen supplies are low during vigorous activity

fermentation

Which of the following secretes erythropoietin

kidney

During fermentation, glucose is broken down into____, which can result in cramping and fatigue

lactate

The contraction of a single muscle fiber can be divided into three stages: the____ period (time between stimulation and initiation of contraction), the____ period (when the muscle shortens), and the____period (when the muscle returns to its former length).

latent, contraction, relaxation

Filament ____ does not change whether a sarcomere is contracted or relaxed

length

Depolarization occurs because

more Na+ diffuse into the cell than K+ diffuse out of it

The movement of actin in relation to myosin, which is explained by the sliding filament model, is responsible for ____

muscle contraction

When the strength of a stimulus is above a threshold level, the muscle contracts and then relaxes. This action is called a ____ and lasts only a fraction of a second

muscle twitch

which of the following is the site of ATP binding and hydrolysis

myosin

During muscle contractions, cross-bridges form between

myosin heads and actin filaments

within the ____ ,a synaptic cleft lies between each axon terminal and muscle fiber. Nerve impulses cause synaptic vesicles to discharge ___

neurotransmitter junction, acetylcholine (ACh)

The hormones ADH and oxytocin, produced by the hypothalamus, are stored in the____ pituitary. ____ is involved in maintaining the water-salt balance in the blood. ____ causes uterine contraction in childbirth and stimulates a mother's milk letdown

posterior, ADH, Oxytocin

Select all of the following that could happen to the neurotransmitter after it binds to the receiving membrane receptor

reabsorbed by the sending membrane, degrades due to lack of Ca+

The neurotransmitter is____ by the sending neuron, where it has been stored in ____ at the axon terminal

released, synaptic vesicles

the neurotransmitter diffuses across the synaptic cleft and binds to receptors in the ____, which generates electrical signals that spread across it and down the ____

sarcolemma, T tubules

This stimulates the release of calcium ions from the ____, which leads to sarcomere contraction

sarcoplasmic reticulum

One motor axon goes to___

several muscle fibers

the sodium-potassium pump functions to pump

sodium ions out of the cell and potassium ions into the cell

skeletal muscle has ____ cells with multiple nuclei. It functions in___ movement of the body

striated, voluntary

When the muscle is not allowed to relax completely between stimuli, ____ occurs. The contractions gradually increases in intensity

summation

The neurotransmitter travels across the____ and then binds to a____ in the membrane of the receiving neuron

synaptic cleft, receptor

Sensory Neurons

take messages to the CNS, Have receptors to detect changes in the environment

Skeletal muscle is attached to the skeleton. A layer of connective tissue covers the skeletal muscle. This tissue contributes to the ____, which attached the muscle to the bone

tendon

When maximal sustained contraction is reached, ____ is achieved. This stage will continue until ____ occurs, and the muscle relaxes even though stimulation continue

tetanus, fatigue

During muscle contraction

the A band remains the same and the I band narrows.

During a resting potential, which of the following situations is true?

the axon is not conducting an impulse and the inside of the axon is negative compared to the outside of the axon

which of the following statements about the resting membrane potential is true

the exterior of the cell has a net positive charge and the interior has a net negative charge

Hyperpolarization, or afterpotential, occurs because

the increased potassium ion permeability lasts slightly longer than the time required to bring the membrane potential back to its resting level

Which of the following is true regarding the action potential of a neuron?

the voltage generated must cross the threshold for it to occur, it's an all-or-none phenomenon, meaning there are no partial action potentials, it occurs when the membrane depolarizes, meaning it has a rapid change in the electrical potential

How are the nervous system and the endocrine system alike?

they both regulate the activities of other systems

After cross-bridges form, phosphate is released and then ADP follows

true

In a contracting muscle, the Z lines come closer together

true

When cross-bridges form and the muscle fibers contract, the actin myofilament slides past the myosin filament

true

An action potential arriving at the presynaptic terminal causes

voltage-gated calcium ion channels to open, and calcium ions to diffuse into the cell