BILD 2: Exam 1

Stefan Leutgeb and Jill Leutgeb

Which of the following is a characteristic of nervous system signals

A.) They allow gradual changes to take place in the body

B.) They usually impact the entire body

C.) They travel in the blood stream

D.) They travel quickly throughout the body

E.) They require a change in ion concentrations to be transmitted

D.) they travel quickly throughout the body

What tissue lines most exchange surfaces of multicellular animals?

A.) Smooth muscle

B.) Neural tissue

C.) Connective tissue

D.) Epithelial tissue

E.) Neural and Epithelial tissue

D.) Epithelial tissue

Which is the name of the epithelial cell surface that faces the outside of the body?

A.) Apical

B.) Interstitial

C.) Botton

D.) Lumen

E.) Basal

A.) Apical

A nerve is a collection of _________.

A.) Nerve cell bodies

B.) Axons

C.) Dendrites

D.) Synapses

E.) Nerve cell nuclei

B.) Axons

The activity of the sodium-potassium pump results in the movement of which ions across the plasma membrane

A.) It pumps sodium and potassium ions into the cell

B.) It pumps sodium ions out of the cell and potassium ions into the cell

C.) It pumps sodium and potassium ions out of the cell

D.) It pumps sodium ions into the cell and potassium ions out of the cell

B.) It pumps sodium ions out of the cell and potassium ions into the cell

Which of these ions is more abundant in the interior of a neuron than in the fluid surrounding the neuron?

A.) Cl^-

B.) Ca⁺⁺

C.) Na⁺

D.) K⁺

D.) K⁺

Which of the following describes the ion channels of a resting neuron

A.) The channels are always open, irrespective of their type

B.) The channels are always closed, but ions move closer to the channels during excitation

C.) The channels are open or closed depending on their type, and are specific as to which ion can traverse them

D.) The channels are open in response to stimuli, and then they close simultaneously

E.) The channels are always open, but the concentration gradients of ions frequently change

C.) The channels are open or closed depending on their type, and are specific as to which ion can traverse them

The Nernst equation specifies the equilibrium potential for a particular ion. This equilibrium potential is a function of ______.

A.) The osmotic gradient

B.) Hydrostatic pressure

C.) The ion concentration gradient

D.) The temperature (thermal) gradient

E.) The electrical gradient

C.) The ion concentration gradient

Action potentials move along axons _________.

A.) By reversing the concentration gradients for sodium and potassium ions

B.) By activating the sodium-potassium “pump” at each point along the axonal membrane

C.) More rapidly in myelinated than in unmyelinated axons

D.) More slowly in axons of large diameter than in axons of small diameter

C.) More rapidly in myelinated than in unmyelinated axons

Which Roman numeral in the graph indicated the point when the membrane potential is closest to the equilibrium potential for potassium?

A.) I

B.) III

C.) V

D.) IV

E.) II

D.) IV

Excitatory postsynaptic potentials (EPSPs) occurring at multiple synapses on the same postsynaptic neuron can add together through ______.

A.) Spatial Summation

B.) Action potentials

C.) Highly branches dendrites

D.) Temporal Summation

A.) Spatial Summation

An inhibitory postsynaptic potential (IPSP) will occur if a membrane is made more permeable to _______.

A.) Potassium ions

B.) cAMP

C.) Acetylcholine

D.) Sodium Ions

A.) Potassium ions

Which of the following is an amino acid that functions as a neurotransmitter at most inhibitory synapses in the brain?

A.) Acetylcholine

B.) Nitric Oxide

C.) GABA

D.) Endorphin

C.) GABA

Where are neurotransmitters released in a synapse?

A.) The presynaptic membrane

B.) The smooth endoplasmic reticulum

C.) Axon hillocks

D.) Cell bodies

A.) The presynaptic membrane

Which of the following structures contains an abundance of axons?

A.) The white matter of the brain and the white matter of the spinal cord

B.) The white matter of the brain and the gray matter of the spinal cord

C.) The gray matter of the brain and the gray matter of the spinal cord

D.) The gray matter of the brain and the white matter of the spinal cord

A.) The white matter of the brain and the white matter of the spinal cord

Which part of the nervous system activates the flight-or-flight response?

A.) Sympathetic

B.) Somatic

C.) Parasympathetic

D.) Enteric

A.) Sympathetic

Which of the following controls balance and coordinates movements in humans?

A.) Hypothalamus

B.) Spinal cord

C.) Cerebrum

D.) Cerebellum

D.) Cerebellum

Which of the following regions arose developmentally from the hindbrain?

III

Which part of the brain are sleep and arousal regulated?

A.) The reticular formation

B.) The cerebral cortex

C.) The limbic system

D.) The basal nuclei

A.) The reticular formation

Which of the following functions is associated with Broca’s region?

A.) Vision

B.) Balance

C.) Speech

D.) Olfaction

E.) Hearing

C.) Speech

How does a neuron transmit information?

A neuron receives information, transmits it along an axon, and transmits the information to other cells via synapses 

• Inactivated Na⁺ channels and open voltage-gated K⁺ channels behind the zone of depolarization prevent the action potential from traveling backwards

• After initiation at the axon hillock, action potentials travel in only one direction: toward the synaptic terminals

Synapse vs. Synaptic Terminal

Synapse is junction between an axon and other cell and a synaptic terminal is the part of the axon that forms this junction

What is an electrical synapse and a chemical synapse?

Electrical synapse is when an electrical current flows from one neuron to another through gap junctions. Chemical synapses use chemical messengers called neurotransmitters to pass information

In a chemical synapse how is the generation of a postsynaptic potential created?

At many chemical synapses, the receptor that binds and responds to neurotransmitters is a ligand-gated ion channel, often an ionotropic receptor. Neurotransmitter binding causes ion channels to open, generating a postsynaptic potential

What are the two types of postsynaptic potentials?

• Excitatory postsynaptic potentials (EPSPs) are depolarizations that bind the membrane potential toward threshold

• Inhibitory postsynaptic potentials (IPSPs) move the membrane potential farther from the threshold or keep the membrane potential from reaching threshold

What happens if two EPSPs are produced in rapid succession? What about if EPSPs are produced nearly simultaneously by different synapses on the same postsynaptic neuron

Individual postsynaptic potentials can combine to produce a larger potentials in a process called summation, when two EPSPs come together temporal summation occurs. In spatial summation, EPSPs produced nearly simultaneously by different synapses on the same postsynaptic neuron add together. Through summation, and IPSP can counter the effect of an EPSP. The summed effect of EPSPs and IPSPs determines whether an axon hillock will reach threshold and generate an action potential 

What are the five major classes of neurotransmitters?

Acetylcholine

• Involved in muscle stimulation, memory formation, and learning

Biogenic Amines

• Include norepinephrine, epinephrine, dopamine, and serotonin; active in CNS and PNS. Dopamine, norepinephrine, epinephrine are made from tyrosine 

• Central role in a number of nervous system disorders

Amino Acids

• Glutamate: acts as a neurotransmitter

• Glycine: inhibitory synapses

• Gamma-aminobutyric acid (GABA): neurotransmitter at more inhibitory synapses in the brain

Neuropeptides

• Short chains of amino acids that also function as neurotransmitters

• Include substance P and endorphins which affect our perception of pain

Gases

• Nitric oxide (NO) and carbon. monoxide (CO) are local regulators

What are the three types of adaptations in mammals?

Form, function, and behavior

Since structure and function are correlated, what clue does anatomy often provide

Clues to physiology or also known as biological function

What do physical laws govern.

Governs strength, diffusion, movement, and heat exchange limit the range of animal forms

Rate of exchange is proportional to what

The rate of exchange is proportional to surface area, while the amount of material that must be exchanged is proportional to volume.

What do larger animals need since they have larger volumes

They need specialized systems to move materials internally

What is the hierarchal organization of the body

Single cells → Tissues → Organs → Organ Systems  

What are the four types of animal tissues

Epithelial, connective, muscle, and nervous

Define epithelial tissue

Covers the outside of the body and lines the organs and cavities within the body

In epithelial tissue what is the part the faces the outside

Apical surface

Function of connective tissue

Holds may tissues and organs together in place

Type of cells found in connective tissue

• Fibroblasts: secrete fiber proteins 

• Macrophages: which engulf foreign particles and cell debris by phagocytosis 

What are the six types of connective tissue

• Fibrous connective tissue is found in tendons, which attack muscles to bones, and ligaments, which connect bones at joints 

• Bone is mineralized and forms the skeleton 

• Adipose tissue stores fat for insulation and fuel 

• Blood is composed of blood cells and cell fragments in blood plasma 

• Cartilage is strong and flexible support material 

Function of muscle tissue

muscle cells consists of filaments of the protein actin and myosin, which together enable muscles to contract

Three types of muscle tissue

• Skeletal Muscle: Striated muscle is responsible for voluntary movement 

• Smooth Muscle: Responsible for involuntary body activities

• Cardiac Muscle: Responsible for contraction of the heart  

Function of nervous tissue

functions in receipt, processing, and transmission of information

What does nervous tissue contain

• Neurons, or nerve cells, which transmit nerve impulses 

• Glia cells, or glia, which support cells 

What are the functions of glia in the central nervous system (5 Types)

• Ependymal cells promote circulation of cerebrospinal fluid 

• Microglia protect the nervous system from microorganisms 

• Oligodendrocytes and Schwann cells from the myelin sheaths around axons 

• Astrocytes provide structural support for neurons, regulate extracellular ions and neurotransmitters, and induce the formation of blood-brain barrier that regulates the chemical environment of the CNS

• Radial glia play a role in the embryonic development of the nervous system 

What are the two major systems of coordination and control in animals

Endocrine and nervous system

What is ganglia?

Clusters of neurons

How are electrical signals created

By the movements of ions across the cell’s plasma membrane

What is membrane potential

the voltage the cell has across its plasma membrane

What is the model of the resting potential

• The concentration of K⁺ is higher in the inner chamber and lower in the outer chamber 

• K⁺ diffuses down its gradient to the outer chamber 

• Negative charge builds up in the inner chamber 

What is the resting potential of a typical neuron

-60 to -80 mV

What is hyperpolarization?

A change in a cell's membrane potential that makes the inside of the cell more negative (further from zero) than its resting state, making it harder for the neuron to fire an action potential by increasing the stimulus needed to reach the firing threshold

What is depolarization?

Reduction in the magnitude of the membrane potential. There is Na⁺ going in

What is repolarization?

Repolarization is the process where a cell, like a nerve or heart muscle cell, returns to its resting, negatively charged state after being excited (depolarized). There is K⁺ going out

Describe the generation of action potentials

Voltage-gated Na⁺ and K⁺ channels respond to a change in membrane potential. When a stimulus depolarizes the membrane voltage-gated Na⁺ channels open, allowing Na⁺ to diffuse into the cell. The movement of Na⁺ into the cell increases the depolarization that causes even more voltage-gated Na⁺ channels. Voltage-gated K⁺ channels also open, but slower. Therefore, a stimulus that causes the membrane voltage to cross threshold results in a massive change in membrane voltage called an action potential 

What is a refractory period

The refractory period is the result of temporary inactivation of voltage-gated Na⁺ channels

What causes an action potential’s speed to increase

Myelin sheaths made by glia

• oligodendrocytes in the CNA and Schwann cells in the PNS

Where are action potentials formed

At nodes of Ranvier which are gaps in the myelin sheath where voltage-gates Na⁺ channels are found

What is saltatory conduction?

Where actions potentials in myelinated axons jump between the nodes of Ranvier

What are mechanisms of terminating neurotransmission

• May diffuse out of the synaptic cleft 

• May be degraded by enzymes 

• May be taken up by the presynaptic terminal/surrounding cells 

How can synapses be strengthened or weakened

• Amount of neurotransmitter released 

• Number of receptors in postsynaptic cell

What are the three stages the nervous system goes through to process information

Sensory input, integration, and motor output

Function of sensory neurons

Transmit information about external stimuli such as light, tough, or smell

Function of interneurons

Integrate (analyze and interpret) the information

Function of motor neurons

transit signals to muscle cells, causing them to contract

What makes up gray matter

neuron cell bodies, dendrites, and unmyelinated axons

What makes up white matter

Bundles of myelinated axons

What is the function of the peripheral nervous system (PNS)

transmits information to and from the CNS and regulates movement and internal environment. Afferent neurons transmit information to the CNS, and efferent neurons transmit information away from the CNS

Where are the cranial nerves

 go in/out of the brain, mostly connected to the head and upper body

Where are the spinal nerves

go in/out of the spinal cord and extend to parts of the body below the head 

What are the two efferent components of the PNS

• The Motor system 

  • Carries signals to skeletal muscles and can be voluntary or involuntary

• Autonomic nervous system 

  • Regulates smooth and cardiac muscles and is generally involuntary 

Function of the enteric nervous system

exerts direct, partially independent, control over the digestive tract, pancreas and gallbladder 

What are the divisions of the autonomic nervous system

• The sympathetic division regulates arousal and energy generation (“fight-or-flight” response) 

• The parasympathetic division has antagonistic effects on target organs and promotes calming and a return to “rest and digest” functions 

In both sympathetic and parasympathetic systems, the pathway for information flow involves which types of neurons

• Preganglionic neurons have cell bodies in the CNS and release acetylcholine as a neurotransmitter 

• Postganglionic neurons of the parasympathetic division release acetylcholine 

The brainstem is made up of what parts

Midbrain and hindbrain

In the brainstem what is the function of the midbrain, pons, and medulla oblongata

• The midbrain contains centers for receipt and integration of sensory information, arousal 

• The pons regulates breathing centers in the medulla 

• The medulla oblongata contains centers that control several functions including breathing, cardiovascular activity, swallowing, vomiting, and digestion 

What part of the brain controls arousal and sleep. What is the diffuse network of neurons that control this called

Brainstem and cerebrum control arousal and sleep. The network of neurons is the reticular formation

How does reticular formation work

Acts as filter of sensory input, blocking familiar and repetitive information. It controls the timing of sleep periods characterized by rapid eye movements and vivid dreams

Functions of the cerebellum

Important for coordination and error checking during motor, perceptual, and cognitive functions. Also coordinates balance

What are the three regions of the diencephalon

• Epithalamus 

  • Includes the pineal gland (sources of melatonin) and generates cerebrospinal fluid from blood 

• Thalamus 

  • The main input center for sensory information to the cerebrum and the main output center for motor information leaving the cerebrum 

• Hypothalamus 

  • Regulates homeostasis and basic survival behaviors such as feeding, fighting, fleeing, and reproducing 

    • Includes the body’s thermostat and central biological clock (suprachiasmatic nucleus) 

Function of the cerebrum

The cerebrum, the largest structure in the human brain, is essential for language, cognition, memory, consciousness, and awareness of our surroundings. The cerebrum controls skeletal muscle contractions and is the center for learning, emotion, memory, and perception. Each lobe of the cerebral cortex (frontal, temporal, occipital, and parietal) is the focus of the specific brain activities. The outer layer of the cerebrum is called the cerebral cortex

Function of somatosensory receptors

Provide information about touch, pain, pressure, temperature, and the position of muscles and limbs

What are the functions of the two hemispheres in the brain

• The left hemisphere is more adept at language, math and logical operations 

• The right hemisphere is stronger at facial and pattern recognition, spatial relations, and nonverbal thinking 

What is Broca’s area

Patients could understand language and not speak. Frontal lobe is active when speech is generated 

What is Wernicke’s area

Patients could speak, but not comprehend speech. Temporal lobe is active when speech is heard 

What are the functions for each lobe in the brain

What is the limbic system and what are its functions

Generation and experience of emotions involve many brain structures, including the amygdala, hippocampus, and parts of the thalamus. These structures are grouped as the limbic system. Storage and recall of emotional memory are dependent on the amygdala, an almond-shaped brain structure near the base of the cerebrum 

What is schizophrenia

Schizophrenia is typically characterized by hallucinations and delusions. Research suggests that schizophrenia affects neuronal pathways that use dopamine as a neurotransmitter. Many drugs that alleviate the symptoms of schizophrenia block dopamine receptors  

What are the two broad forms of depressive illness

• major depressive disorder, patients have a persistent lack of interest or pleasure in most activities 

• Bipolar disorder is characterized by manic (high mood) and depressive (low-mood) phases 

• Treatments for these types of depression include drugs that increase the activity of biogenic amines in the brain 

What is Alzheimer’s Disease

Mental deterioration (dementia) characterized by confusion and memory loss. There is also massive shrinkage of brain tissue, reflecting the death of neurons in many areas of the brain. The neurofibrillary tangles observed in Alzheimer’s Disease are primarily made up of tau protein 

What is Parkinson’s Disease

Motor disorder caused by death of dopamine-secreting neurons in the midbrain. It is characterized by muscle tremors, flexed posture, and a shuffling gait 

What are the four basic functions sensory pathways have in common

Sensory reception, transduction, transmission, and perception

Function of sensory reception

A sensory receptor converts stimulus energy into a change in the membrane potential. Sensory receptors are sensory cells (sensory neurons or non-neironal receptors/organs). They interact with stimuli, both inside and outside the body  

What happens during transduction

Conversion of stimulus energy into a change in the membrane potential of a sensory receptor/sensory neuron 

What occurs during transmission

Sensory cells without axons release neurotransmitters at synapses with sensory neurons through the nervous system as action potentials

What occurs during perception

Stimuli from different sensory receptors travel as action potentials along dedicated neural pathways. The brain distinguishes stimuli from different receptors based on the path by which the action potentials arrive

What is amplification and sensory adaption

• Amplification is strengthening of a sensory signal during transduction 

• Sensory adaptation is a decrease in responsiveness to continued stimulation 

What are the 5 types of sensory receptors

Mechanoreceptors, chemoreceptors, electromagnetic receptors, thermoreceptors, and pain receptors (nociceptors)

Function of mechanoreceptors

Sense physical deformation caused by formed of mechanical energy 

• They typically have mechanical gated ion channels, can be linked to structures that end outside the cell, such as “hairs” (cilia) 

• Bending or stretching of the structure generates tension and alters the permeability of the ion channels and this results in changes to the membrane potential 

• The mammalian sense of touch relies on mechanoreceptors that are dendrites of sensory neurons 

Function of chemoreceptors

Transmit information about the total solute concentration of a solution 

• Others respond to specific molecules in body fluids 

• When a stimulus molecule binds to a chemoreceptor the chemoreceptor become either more or less permeable ions 

Function of electromagnetic receptors

Detect electromagnetic energy such as light, electricity, and magnetism 

• The platypus has electroreceptors on its bill that can detect the electric field generated by prey 

• Many animals can migrate using Earth’s magnetic field to orient themselves