Exam 1 SG BBH 203

Neurons

– Electrogenic cells that allow for rapid
signaling throughout the body
– About how many in the human brain? about 86 billion

Neurons- Cell body (soma)

The usual organelle; axon hillock

Neurons- Dendrites=garden (these are branch-like structures)

Dendrite Spines- Small protrusions on dendrites that receive signals from other neurons

Neurons- axon=short word, long structure!

Axon collaterals- side branches of an axon that allow a neuron to communicate with multiple other neurons; Axon terminals- the ends of axons that release neurotransmitters to transmit electrical impulses to other cells.

Glia= glue (keeps everything together)/ asset (awesome)- 6 major glial cells

Astrocytes (cns), Satellite Cells (PNS), Oligodendrocytes (CNS), Schwann Cells (PNS), Ependymal cells (CNS), Microglia (CNS)

Astrocytes (CNS)

clearing excess neurotransmitters, stabilizing and regulating the blood-brain barrier, and promoting synapse formation. Maintain chemical & structural environment

Satellite Cells (PNS)

stem cells that help muscles grow and repair themselves.

Oligodendrocytes (CNS) [COPS= CNS>oligodendrocytes; PNS>Schwann Cells)

cells in the central nervous system (CNS) that produce myelin, which insulates nerve fibers. Produces multiple axons

Schwann Cells [COPS= CNS>oligodendrocytes; PNS>Schwann Cells)

Schwann cells are glial cells that support and insulate peripheral nerve cells. They are the most common cell type in peripheral nerves.  produce one axon

Ependymal Cell (CNS)

Produce & regulate cerebrospinal fluid

Microglia (CNS)

Immune cells of the nervous system

Sensory- Afferent=accept

Any information that is incoming

Motor- Efferent= exit

Information that is outgoing

Myelin Sheath

an insulating layer, or sheath that forms around nerves, including those in the brain and spinal cord

Cerebrospinal fluid

clear, watery fluid that protects and nourishes the brain and spinal cord

Central Nervous System

the part of the body that controls and coordinates all of its functions. It's made up of the brain and spinal cord, which work together to process sensory information and respond by coordinating body activities. 

Peripheral Nervous Sytem The peripheral nervous system is a network of nerves that runs throughout the head, neck, and body

The peripheral nervous system is a network of nerves that runs throughout the head, neck, and body

Central nervous sytem-Nuclei(CNS) of things that are ball like (just like the cell bodies they contain)

groups of nerve cell bodies in the central nervous system (CNS) that give rise to cranial nerves

Central Nervous Stem- Tracts (tracts =think railroad tracks, which are long, parallel lines, just like axes bundled together

are bundles of nerve fibers that act as neural pathways

Central Nervous System- Commisure

a band of nerve tissue connecting the two hemispheres of the brain, the two sides of the spinal cord, etc.

Peripheral Nervous System- Ganglia {Ganglia are a gang (Set) of glia and a neuronal cell bodies

groups of nerve cell bodies in the peripheral nervous system (PNS) that carry signals to and from the central nervous system (CNS)

Peripheral Nervous System- Nerves= Tracts in CNS, nerves in PNS

the nerves that connect the brain and spinal cord to the rest of the body

Grey Matter { Groups everything but myelinated axons}

Nuclei- groups of nerve cell bodies in the brain and spinal cord, Ganglia- groups of nerve cell bodies in the peripheral nervous system (PNS) that carry signals to and from the central nervous system. Neuronal/glial cell bodies (somata), and Dendrites & axons (w/o myelin)

white mater [white matter= wires of the nervous system]

Axons (w/myelin)

Grey matter vs white matter

Functionally similar grey-matter densities = Nucleus (CNS)/Ganglion (PNS); Bundles of axons (myellinated or unmyelinated)= tracts (cns)/ nerves (pns )

Gyrus [when you’re on top (gyro, as peaks are atop sulci]

sticking out

Sulcus [sulci] [when you’re at your lowest]

grove-space fluid

Directionality- relative to neuro axis

Rostral (“beak”) & Caudal (“tail”); Dorsal (“back”) & Ventral (“Belly”). Cephalic Flexure- At junction between forebrain and midbrain.

Directionality- Relative to Body

-Superior & inferior, posterior & anterior

Orientation and Directionality

Media- (middle), lateral (side); Ipsilateral (same side), & Contralateral (opposite side), Bilateral (Both sides); Decussation: structure crosses or switches side- Ex: left hand works right side of brain

Anatomical Planes

Coronal, sagital, Horizontal/axial. Midsagittal= that special plane that bisects the brain (into left & right hemispheres) along the longitudinal fissure

Cerebrum/Cerebral hemispheres (Cerebrum)- Corpus Callosum [corpus callosum=sums your brain up by connecting two halves of the cerebrum)

A think candle of nerve fibers that connect the brains left and right hemispheres

Cerebrum/Cerebral hemispheres (Cerebrum)- Basal Ganglia-(body goals (basal ganglia + selects bodily movements)

a group of nuclei in the brain that control movement, emotions, and reward.

Cerebral Cortex [FTOP= Frontal, temporal, occipital, parietal)

The cerebral cortex is the outermost layer of the brain, made up of gray matter and responsible for most of the brain's information processing. It's involved in many higher brain functions, including memory, thinking, and consciousness. 

Frontal Lobe- Move (motor cortices, Brocas area, which is also motoric) to the front of the line, where you get to make the important decisions (prefrontal cortex)

the part of the brain at the front that controls thinking, movement, memory, and social skills primary motor cortex/precentral gyrus, premotor cortex & supplemental motor area, Broca’s area, prefrontal corte,

Parietal Lobe [Pariahs are sensitive to criticism, just as the Parietal lobe is sensitive to touch (somatosensory), primary somatosensory cortex/ post central gyrus, posterior parietal cortex

a part of the brain that processes sensory information, such as touch, pain, and temperature.

Occipital Lobe (occipital=ocular (seeing), Primary visual cortex, calcimine fissure (you can’t see out of calcified (Calcarine eyes)

the part of the brain that processes visual information.

Temporal lobe [temporal relates to timing which is critical for music (auditory) and language (wernickes area)

Hippocampus, amygdala, primary auditory cortex, wernickes area

Longitudinal fissure [longitudinal fissure=slices your brain in half long way]

Neocortex, allocortex, central sulcus [central sulcus is in a roughly coronal plane] a deep groove in the brain that separates the left and right cerebral hemispheres

Diencephalon

Thalamus, hypothalamus [hypothalamus controls [homeostasis] - autonomic nervous system (regulate by homeostasis not a part of it)

Brainstem [MiPoMe (midbrain, pons, medulla, from most rostral to most caudal)

Midbrain, pons, medulla, cranial nerves (branch off from brainstem, but not a part of it)

Cerebellum {cerebrellum rings to the bell to keep everything coordinate)

a small, fist-sized part of the brain that controls balance, posture, and voluntary muscle movement.

Neural Networks

computational models that process data in a way that mimics the human brain.

Brain Connectome

a comprehensive map of neural connections in the brain,

Spinal Cord [call the lawyers Steve cox=cervical, thoracic, lumbar, sacral, coccygeal]

Cervical, thoracic, lumbar, sacral, coccygeal. send motor commands from the brain to the body, send sensory information from the body to the brain, and coordinate reflexes.

Meninges [the meninges PAD (pia, arachnoid, dura) the brain from inside to out.

Dura mater, arachnoid mater, pia mater, subarachnois mater

Ventricular system [Ventricles are lined with ependymal cells]

a network of fluid-filled spaces in the brain that produce and circulate cerebrospinal fluid (CSF)

Anterior [CNS] circulation

the part of the brain's blood supply that comes from the internal carotid arteries (ICAs)

Posterior [CNS] circulation

derives blood from the bilateral vertebral arteries (VA)

Dural sinuses

collect blood from different venous systems, drain into the internal jugular veins, and are resistant to compression due to their position between rigid layers.

Blood-brain barrier

a semipermeable membrane that protects the brain from harmful substances in the blood.

Electrical Potential [electrical potential is like the electrical pressure on a charge

the amount of energy needed to move a unit of charge from one point to another in an electric field. 

Membrane Potential (Vm)- the voltage difference between the inside and outside of a biological cell.

Resting membrane potential (vrest)- the electrical voltage difference across a cell membrane when a cell is not actively sending signals

Threshold Potential- the minimum level of depolarization that causes a neuron to fire an action potential

Na*-K* Atpase

The Na⁺/K⁺-ATPase, also known as the sodium-potassium pump, is a vital membrane protein that maintains the balance of sodium and potassium ions across the cell membrane. This pump uses energy derived from ATP to transport three sodium ions out of the cell and two potassium ions into the cell against their concentration gradients.

Depolarization/ hyperpolarization In common language, polarization (for
example, in politics) has a negative connotation. When you depolarize the neuronal
membrane, you’re removing that negativity and making it more positive. When you
hyperpolarize, you’re taking something that’s already negative (resting membrane
potential) and making it more negative.]

• Depolarization:

  • Membrane potential becomes less negative.

  • Occurs when Na⁺ channels open, allowing Na⁺ to enter the cell.

  • Essential for initiating and propagating action potentials.

• Hyperpolarization:

  • Membrane potential becomes more negative.

  • Happens when K⁺ channels open (K⁺ leaves the cell) or Cl⁻ enters the cell.

  • Inhibits action potential initiation by moving the membrane potential further from the threshold.

Electrochemical gradient-Chemical gradient [Chemical gradient depends only on relative ion
concentration (extracellular vs. intracellular)]

A chemical gradient is the difference in concentration of a molecule or ion across a membrane or in a solution

Ion Channels

proteins that act as pores in a cell membrane, allowing certain ions to pass through.

Graded (passive) potentials -[Grades in school come in many varieties (e.g., A, A-,
B+, B, etc.). If you invest more effort into a class, you’ll get a higher grade. Graded
potentials get bigger when the input(s) that generate them are larger.]

primarily generated by sensory input, causing a change in the conductance of the membrane of the sensory receptorcell.

Action potential [Rising up to act (towards peak of AP), falling down to rest (back
to Vrest )]

oRising phase
o Falling phase
o Afterpotential

Voltage-gated Na + channels [SIRP (sodium-in-rising-phase)=”stay informed, react
promptly”]

transmembrane proteins that allow sodium ions to flow into cells in response to changes in voltage

Voltage-gated K+ channels

proteins that open to allow potassium ions to pass through the cell membrane in response to changes in voltage

Nodes of Ranvier

gaps in the myelin sheath of a neuron's axon, allowing for the rapid propagation of electrical signals along the axon through a process called saltatory conduction, essentially "jumping" from node to node and significantly increasing the speed of nerve impulse transmission

Nodes of Ranvier - Saltatory conduction

the propagation of action potentials along myelinated axons from one node of Ranvier to the next, increasing the conduction velocity of action potentials.

Synapses

Chemical synapses
o Electrical synapses
o Presynaptic neuron
o Postsynaptic neuron
o Excitatory synapse
o Inhibitory synapse

Neurotransmitters [Giant Gorillas Swing Down Near Acorns=glutamate, GABA,
serotonin, dopamine, norepinephrine, acetylcholine]

Glutamate

GABA
o Serotonin
o Dopamine
o Norepinephrine
o Acetylcholine

Chemical synaptic transmission [Saavy Artists Create Exceptional Beauty, Presence, and
Charm:

1. Synthesis and storage of NTs
2. Action potential reaches axon terminal
3. Calcium diffuses into axon terminal
4. Exocytosis of synaptic vesicles
5. Binding of NTs to postsynaptic receptors
6. Postsynaptic effect

Postsynaptic potentials (PSPs

Excitatory postsynaptic potentials (EPSPs)
o Inhibitory postsynaptic potentials (IPSPs)

In 1-3 sentences, identify the distinction in the roles played by Broca’s and
Wernicke’s areas relative to speech and language.

Broca's area is primarily involved in speech production and language processing, aiding in the formation of coherent sentences. On the other hand, Wernicke's area is crucial for language comprehension, enabling us to understand spoken and written language. These regions work together to facilitate seamless communication.

In 2-4 sentences, explain why the brain receives a disproportionate amount of
arterial (oxygenated) blood relative to its size, and identify a potential consequence
of depriving the brain of arterial blood.

The brain, despite being only about 2% of the body's weight, consumes roughly 20% of its oxygen supply because of its high metabolic activity and energy demands for proper functioning and maintaining neural connections. Depriving the brain of arterial blood can lead to severe consequences like brain damage, cognitive impairments, or even stroke due to the lack of oxygen and nutrients.

In 1-3 sentences, identify the factor that determines the chemical gradient on a
particular variety of ion.

The chemical gradient of a particular ion is primarily determined by the difference in ion concentration across the cell membrane. This gradient is influenced by active transport mechanisms, such as ion pumps, and passive processes, like diffusion, that work to establish and maintain the gradient.

In 1-3 sentences, explain what is meant by the “all-or-nothing” principle of action
potential generation.

The "all-or-nothing" principle states that once an action potential is initiated in a neuron, it will travel along the axon without decreasing in strength. This means that either the neuron fully responds to a stimulus and generates an action potential, or it doesn't respond at all if the stimulus doesn't reach the threshold level. There is no partial or weak action potential; it's an all-or-nothing event.

In 1-3 sentences, describe the phenomenon of saltatory conduction in myelinated
axons

Saltatory conduction is the process by which electrical impulses rapidly travel along myelinated axons, jumping from one node of Ranvier to the next. This "hopping" mechanism significantly increases the speed of nerve signal transmission compared to unmyelinated axons, where impulses must travel continuously along the entire length of the axon. This efficient conduction ensures quick and coordinated neural communication.

Botulinum toxin interferes with the normal function of synaptic fusion proteins. In
1-3 sentences, explain why presynaptic neurons might fail to release
neurotransmitters in the presence of botulinum toxin, referencing both synaptic
fusion proteins and synaptic vesicles

Botulinum toxin disrupts the function of synaptic fusion proteins, which are essential for the docking and fusion of synaptic vesicles with the presynaptic membrane. This interference prevents the vesicles from releasing neurotransmitters into the synaptic cleft, leading to a failure in synaptic transmission. Without this crucial step, neural communication is impaired.