Nervous Systems and Brain Cells - Week 7

Question 1

CENTRAL NERVOUS SYSTEM

Answer 1

Is made up of the BRAIN STEM and SPINAL CORD:

The brain controls how we think, learn, move, and feel.

The spinal cord carries messages back and forth between the brain and the nerves that run throughout the body.

CNS is responsible for receiving, processing and responding to sensory info

Both the brain and the spinal cord are protected by bone: the brain by the bones of the skull, and the spinal cord by vertebrae , a set of ring-shaped bones. They’re both cushioned by layers of membranes (called meninges) and cerebrospinal fluid. The fluid flows through hollow spaces in the brain called ventricles and around the spine in the spinal column. It protects the central nervous system, nourishes it, and takes away waste products.

Question 2

BRAIN STEM

Answer 2

Connects the cerebrum of the brain to the spinal cord and cerebellum.

It controls basic functions such as breathing and heart rate.

It is composed of three sections in descending order: the midbrain, pons and medulla oblongata

Question 3

CEREBRUM

Answer 3

Is the largest part of the brain and it is located at the front and top of the skull.

It is split into two halves called ‘hemispheres’.

It comes from Latin name meaning ‘brain’.

Is responsible for higher cognitive functions such as thinking, memory, and perception

Question 4

CEREBELLUM

Answer 4

It is responsible for motor movement and balance (posture & balance, mental function, movement, motor learning, vision).

There are 4 lobes of the cerebrum (frontal, parietal, occipital, temporal).

It holds more than half of the neurons (cells that make up your nervous system).

Question 5

SPINAL CORD

Answer 5

Serves as a pathway for transmitting sensory and motor signals between the brain and the rest of the body.

It is part of the Central Nervous System

Question 6

PERIPHERAL NERVOUS SYSTEM

Answer 6

It is part of your nervous system that consists of nerves and ganglia and lies outside of your brain and spinal cord.

It plays key role in both sending information from different areas of your body back to your brain, as well as carrying out commands from your brain to various parts of your body.

The PNS is subdivided into Somatic and Automatic Nervous System.

Question 7

SOMATIC NERVOUS SYSTEM

Answer 7

It is a component of PNS.

It controls intentional processes and is responsible for VOLUNTARY movements and sensory perception.

It receives sensory input form the external environment and delivers motor/ muscle output to skeletal muscles.

*Sensory output is received through the dorsal roots to the spinal cord
*Motor outputs is delivered via the Ventral roots of the spinal cord to the muscle

This system allows us to control our movements and respond to stimuli consciously.

The brain receives sensory information (of touch) at the somatosensory cortex and produces behaviour by modulating motor output form the primary motor cortex.

There are 6 areas that the nerves join the CNS - cranial, cervical, thoracic, lumbar, sacral, coccygeal and there are 4 lobes of the cerebrum.

e.g., a somatic reflex -> pulling a hand away after touching a hot stove

Question 8

AUTONOMIC NERVOUS SYSTEM

Answer 8

It is a component of PNS.

It regulates INVOLUNTARY functions of the body, such as heart rate, digestion, breathing and blood pressure.

It regulates survival mechanisms e.g., heart rate increase and start sweating.

It consists of two divisions: the sympathetic and parasympathetic, which are parallel systems that work in opposition to each other

Question 9

SYMPATHETIC NS (AUTONOMIC NS) - PERIPHERAL NS

Answer 9

4 F’s (fight, flight, fright/ freeze, fornicate/ fawn).

It is in the Automatic Nervous System, which is part of Peripheral Nervous System. It extends from thoracic and lumbar spine and has short preganglionic (cell body) nerves and long postganglionic nerves.

It carries signals that put your body on alert. It prepares the body for ‘fight or flight’ responses in danger or stressful situations.

Question 10

PARASYMPATHETIC NS (AUTONOMIC NS) - PERIPHERAL NS

Answer 10

It is a network of nerves that relaxes your body after periods of stress and danger.

It is non emergency, which is responsible for (digestion, growth, immune response, energy storage.

It extends from cranium and sacral spine (craniosacral) and has long preganglionic nerves and short postganglionic nerves

It controls homeostasis and the body at rest and is responsible for the body’s “rest and digest” function

Question 11

PERIPHERAL NERVES

Answer 11

They reside outside your brain and spinal cord. They relay information between your brain and the rest of your body.

It is made up of 12 Cranial Nerves, which come out of the opening in the skull and 31 Spinal Nerves (Cervical Nerves = 8 pairs; Thoracic Nerves = 12 pairs; Lumbar Nerves = 5 pairs; Sacral Nerves = 5 pairs; Coccygeal Nerves = 1 pair).

Question 12

LOBES OF CEREBRUM CORTEX

Answer 12

The cerebrum consists of two cerebral hemispheres the outer layer called the cortex (grey matter) and the inner layer (white matter).

There are four lobes in the cortex, the frontal lobe, parietal lobe, temporal lobe, occipital lobe

Question 13

FRONTAL LOBE

Answer 13

It is the front-most part of your brain, which is directly behind the forehead.

Is responsible for executive functions like judgement, higher order function such as attention, thinking, memory, emotions and reasoning.

It controls over voluntary movement and many abilities (including the way you think, how you move and how you remember things.

It’s also a key part in your social skills, and helps you understand and control how you talk, behave and interact with others.

It is in the Primary Motor Cortex and Central Sulcus separates it with Parietal Lobe

Question 14

PARIETAL LOBE

Answer 14

It is located near the back and top of the head in the Primary Somatosensory Cortex.

It is responsible for some of the sensory processing such as touch, sensation, tactile, proprioception, body awareness and space.

Eg. they inform us about objects in our external environment through touch (i.e., physical contact with skin) and about the position and movement of our body parts (proprioception).

Question 15

TEMPORAL LOBE

Answer 15

It is a part of your brain that helps you use your senses to understand and respond to the world around you.

It is responsible for smell and have olfactory nerves, taste, perception, auditory processing, storing and retrieving memories, and understanding language, managing emotions

Question 16

OCCIPITAL LOBE

Answer 16

It sits at the back of the head and are responsible for visual perception, including colour, form and motion.

The occipital lobes transmit visual information to the temporal lobes, which aids in giving meaning to visual information, storing memories, and responding to external stimuli in the world.

Question 17

HORMONES

Answer 17

Hormones are chemicals that coordinate different functions in your body by carrying messages through your blood to your organs, skin, muscles and other tissues. These signals tell your body what to do and when to do it.

Hormones help coordinate your body’s functions, from metabolism to growth and development, emotions, mood, sexual function and even sleep.

*Hypothalamus & Pituitary (many different hormones)
*Pineal gland (melatonin)

Question 18

HYPOTHALAMUS

Answer 18

It is the size of an almond, which is located in the ventral brain, which is below the third ventricle (below the) thalamus and above the pituitary gland.

Its main function is to keep your body in a stable state called ‘‘homeostasis. It is directly influencing your autonomic nervous system or by managing hormones.
It produces and releases hormones from the pituitary gland (cortisol, vasopressin, oxytocin).
The hypothalamus and pituitary gland form a complex regulatory system that controls a wide range of bodily functions, including growth, metabolism, reproduction, and stress response.

Question 19

PITUITARY GLAND

Answer 19

Often referred as the ‘master gland’ which is below the hypothalamus.

It receives signals for the hypothalamus and releases hormones that control activity of other endocrine glands throughout the body.

These hormones include growth hormone, thyroid-stimulating hormone, adrenocorticotropic hormone, follicle-stimulation hormone, luteinising hormone, and prolactin

Question 20

PINEAL GLAND

Answer 20

It is a very small gland in the centre of your brain. The pineal gland makes a hormone called melatonin. Melatonin helps your body control day-night sleep patterns and your internal body clock (circadian rhythms).

Question 21

ANTERIOR (FRONT) LOBE OF PITUITARY

Answer 21

It regulates growth, metabolism, and reproduction through the hormones that it produces.

Question 22

POSTERIOR (BACK) LOBE OF PITUITARY

Answer 22

Plays an important role in fine motor coordination, specifically in the inhibition of involuntary neurotransmitters, especially GABA

Question 23

CORTISOL (HORMONE)

Answer 23

Is a steroid hormone that is produced by your 2 adrenal glands, which sit on top of each kidney. When you are stressed, increased cortisol is released into your bloodstream.

Question 24

VASOPRESSIN (HORMONE)

Answer 24

It is a nonapeptide synthesized in the hypothalamus, which controls of the body’s osmotic balance, blood pressure regulation, sodium homeostasis, and kidney functioning.

Regulation of body fluid (decreases water excretion by the kidneys by increasing water reabsorption in the collecting ducts)

Question 25

OXYTOCIN

Answer 25

Is a hormone that makes you feel love and trust. It is involved in childbirth and breastfeeding. It’s sometimes known as the ‘love hormone’.

Oxytocin controls several processes in the body and also helps nerve cells in the brain to send messages to each other. It is important for social bonding.

Question 26

BBB

Answer 26

Blood Brain Barrier, which protects and nourishes the brain.

It regulates molecules that can move in and out (e.g., from brain supply to a tissue).

It shields the brain from toxic substances in the blood, supplies brain tissues with nutrients, and filters harmful compounds from the brain back to the bloodstream.

Only highly lipophilic drugs and small uncharged molecules can cross from blood capillaries to cerebrospinal fluid (CSF) by diffusion.

*In Parkinson’s disease there is low dopamine (L dopa is prerequisite for dopamine that doesn’t have to go through the blood brain)

Question 27

CEREBROSPINAL FLUID (CSF)

Answer 27

It protects, removes the waste and nourishes the brain. It provides cushion to delicate brain and spinal tissue.

Cerebrospinal fluid (CSF) is a clear, colourless body fluid in the Ventricle system, which is found within the tissue that surrounds the brain and spinal cord of all vertebrates.

CSF (flows down the spinal cord and then gets recycled and goes back to the brain) is made by the choroid plexus in the lateral and third ventricles.

Question 28

GLIAL CELLS

Answer 28

Glial cells, or neuroglia, are cells that surround the neurones of the central nervous system embedded between them, providing both structural and physiological support. They are supporting cells of neurons.

Glial cells exist in the both central nervous system (CNS) and the peripheral nervous system (PNS). The most notable glial cells include oligodendrocytes, astrocytes (radial), microglia, and ependymal cells in the CNS and Schwann cells, satellite cells, and enteric glial cells in the PNS.

Question 29

AMINO ACID AND GLUCOSE

Answer 29

Are important nutrients that are actively transported across to CSF by proteins in the capillary membrane called ‘transporters’. Transportation across the membrane requires energy use.

Question 30

VENTRICLES

Answer 30

It is a communicating network of cavities filled with cerebrospinal fluid (CSF) and located within the brain parenchyma.
The cerebral ventricular system is made up of 4 ventricles that include 2 lateral ventricles (1 in each cerebral hemisphere), the 3 ventricle in the diencephalon (he third ventricle is a narrow, funnel-shaped structure that lies in the centre of the brain. It lies below the corpus callosum and body of the lateral ventricles, between the two thalami and walls of hypothalamus, and above the pituitary and midbrain), and the 4 ventricle in the hindbrain.

Question 31

BRAIN MENINGES

Answer 31

Meninges are three membranes layers that cover and protect your brain and spinal cord (central nervous system). These membranes — the dura mater, arachnoid mater and pia mater — protect and anchor your brain and provide a support system for blood vessels, nerves, lymphatics and the cerebrospinal fluid that surrounds your central nervous system

Question 32

NEURONS

Answer 32

They are nerve cells that send messages all over your body to allow you to do everything from breathing to talking, eating, walking, and thinking (huge network communication and complex processing).

Most have 4 main parts:
-Soma (cell body)
-Dendrites
-Axon
-Presynaptic Terminals

Neurons are classified based on the shape and type of dendrites they have.

There are two main classifications: stellate (star-shaped) and pyramidal (triangular) neurones.

They can be categorised as having spines (spinous) or not having spines (aspinous) on the dendrites. The presence and absence of dendritic spines is involved in learning and memory process. Dendritic trees constantly change, either growing or receding, which aids in neuroadaptation. The number of dendrites a neuron has, the more information it can gather.

There are 100 billion neurons in the human brain and even more glial cells.

Question 33

SOMA

Answer 33

Cell body of a neuron contains the nucleus (DNA/ mRNA) and other structures common to living cells. These structures support the chemical processing of the neuron; the most important of which is the production of neurotransmitters.

The soma where proteins are made to be transported throughout the axon and dendrites and synapses.

Question 34

DENDRITES

Answer 34

They are the receiving or input portions of a neuron. They are usually short, narrow and highly branched structures. In neurons, these dendrites resemble a tree or branches of a tree, extending from the cell body of the nerve cell.

Question 35

AXON

Answer 35

Carries information TO the terminal (presynaptic) boutons (or buttons).

Axon, also called nerve fibre, portion of a nerve cell (neuron) that carries nerve impulses away from the cell body. A neuron typically has one axon that connects it with other neurons or with muscle or gland cells.

Neurones are classified by axon length:
Gogli type 1 - long internuncial; Gogli type 2 - small interneurons

Question 36

PRESENAPTIC TERMINAL

Answer 36

The presynaptic terminal is separated from the neuron or muscle or gland cell onto which it impinges by a gap called the synaptic cleft.

The presynaptic terminal is at the end of an axon and is the place where the electrical signal (the action potential) is converted into a chemical signal (neurotransmitter release).

Question 37

NEURITES

Answer 37

Neurites are small processes on developing neurons that ultimately grow out into axons or dendrites.

Neurons create connections via extensions of their cellular body called axons and dendrites, which are commonly referred to as “neurites” or “processes”.

Question 38

NEUROTRANSMITTERS

Answer 38

Neurotransmitters are your body’s chemical messengers, which is released at the end of a nerve fibre by the arrival of a nerve impulse and, by diffusing across the synapse or junction, effects the transfer of the impulse to another nerve fibre, a muscle fibre, or some other structure.

They carry messages from one nerve cell across a space to the next nerve, muscle or gland cell.

They include serotonin, dopamine, glutamate, and acetylcholine. Neurotransmitters serve several functions, such as regulating appetite, the sleep-wake cycle, and mood.

Question 39

NEURAL CONNECTIONS

Answer 39

Neural pathway - If an electrical signal passes down an axon, its tip releases chemicals called neurotransmitters into the synapse. These neurotransmitters tell the receiver cell to either activate its own electrical charge, which sends the signal to the next neuron in the chain, or tell the receiver cell to stay quiet.

Question 40

WHITE VS GREY MATTER:

Answer 40

Grey matter: made up of neurone cell bodies

White matter: made up of the accents, which are covered by the myelin, this fatty white substance that allows neural signals to travel from the cell body down the accent to communicate with others.

Question 41

MYELIN

Answer 41

Myelin is an insulating layer (coating), or sheath that forms around each nerve cell (neurons), including those in the brain and spinal cord.

It is present in Central Nervous System and Peripheral Nervous System. It is made of lipids, water, proteins and fatty substances. This myelin sheath allows electrical impulses to transmit quickly and efficiently along the nerve cells.

Question 42

TYPES OF BRAIN CELLS

Answer 42

Major cell types of the central nervous system comprise NEURONS, GLIA CELLS (astrocytes, oligodendrocytes, ependymal cells, and microglia), choroid plexus cells, cells related to blood vessels and coverings

Question 43

CLASSIFICATION BY NEURITES (AXONS AND DENDRITES)

Answer 43

Cells can be unipolar, bipolar, multipolar -> defined by the number of neurites connected to the soma.

Pyramidal cells: an apical dendrite extends from the apex of the pyramidal cell soma.

Basilar dendrites are connected to the base of the soma (not the axon).

Question 44

DENDRITES SPINE ABNORMALITIES

Answer 44

Dendrites close to amyloid plaques have less spines = less synapses for communication

Question 45

AFFERENT VS EFFERENT NEURONS

Answer 45

Afferent (Retrograde) neurons - arriving TO (in) the connection –> are sensory neurons that carry nerve impulses from sensory stimuli towards the central nervous system and brain.

Efferent (Anterograde) neurons - exiting FROM (out) the connection are motor neurons that carry neural impulses away from the central nervous system and towards muscles to cause movement.

Synaptic Connection - gap - neurons are not connected physically but they communicate

Question 46

GLIAL CELLS IN CNS

Answer 46

Astrocytes
Oligodendrocytes
Ependymal
Microglia

Question 47

ASTROCYTES CELLS (GLIAL CELL - CNS)

Answer 47

Astrocytes are a subtype of glial cells that make up the majority of cells in the human central nervous system (CNS). They perform metabolic, structural, homeostatic, and neuroprotective tasks such as clearing excess neurotransmitters, stabilizing and regulating the blood-brain barrier, and promoting synapse formation.

Question 48

OLIGODENDROCYTE (GLIAL CELL -CNS)

Answer 48

Oligodendrocytes are the myelinating cells of the CNS that allow the fast and efficient transfer of neuronal communication through the myelination of axons. By covering axons with laminated, lipid-rich membranes, oligodendrocytes produce the electric insulation needed for fast saltatory axonal conduction

Question 49

EPENDYMAL (GLIAL CELL - CNS)

Answer 49

It is a type of glial cell. These cells line in the ventricles (neurogenesis) in the brain and the central canal of the spinal cord, which become filled with cerebrospinal fluid.

Question 50

MICROGLIA (GLIAL CELL - CNS)

Answer 50

From micro (small); glia (glue). Responsible for phagocytosis, which is removing dead or degenerating neurons of glia - they are in charge of keeping everything clean.

Microglia are resident cells of the brain that regulate brain development, maintenance of neuronal networks, and injury repair.

Question 51

PLASMA (CELL) MEMBRANE

Answer 51

Cell membrane of neuron (or glia cells).

It is the membrane found in all cells that separates the interior of the cell from the outside environment.

The plasma membrane separates the inside of the cell (intracellular fluid) from the outside of the cell (extracellular fluid).

The plasma membrane protects the cell from its external environment, mediates cellular transport, and transmits cellular signals. The fluid mosaic model describes the plasma membrane structure as a mosaic of phospholipids, cholesterol, proteins, and carbohydrates

Question 52

PHOSPHOLIPID

Answer 52

Phospholipids are major membrane lipids that consist of lipid bilayers. This basic cellular structure acts as a barrier to protect the cell against various environmental insults

*Will let uncharged molecules through, but not ions
*Ions require channels in the form of large protein molecules

Question 53

NUCLEUS

Answer 53

The nucleus serves both as the repository of genetic information and as the cell’s control centre. DNA replication, transcription, and RNA processing all take place within the nucleus.

Contains DNA (deoxyribonucleic acid) to provide
information for protein synthesis in the neuron.

Question 54

ENDOPLASMIC RETICULUM

Answer 54

The endoplasmic reticulum can either be smooth or rough, and in general its function is to produce proteins for the rest of the cell to function. The rough endoplasmic reticulum has on it ribosomes, which are small, round organelles whose function it is to make those proteins.

Question 55

RIBOSOMS (IN ROUGH ENDOPLASMIC RETICULUM)

Answer 55

Translate protein making instructions
(from messenger ribonucleic acid (mRNA).

Question 56

POLYRIBOSOMS

Answer 56

Polyribosomes - free floating ribosomes working together on the same strand of mRNA

Question 57

GOGLI APPARATUS

Answer 57

Golgi Apparatus (Camillo Golgi 1898) - sorting of proteins for delivery to specific parts of the neuron.

It is responsible for transporting, modifying, and packaging proteins and lipids into vesicles for delivery to targeted destinations

Question 58

MITOCHONDRION

Answer 58

Mitochondrion - Energy producers of the cell.

Mitochondria are membrane-bound cell organelles (mitochondrion, singular) that generate most of the chemical energy needed to power the cell’s biochemical reactions.

Question 59

ADENOSINE THRIPHOSPATE

Answer 59

Adenosine triphosphate (ATP) is the source of energy for use and storage at the cellular level. The structure of ATP is a nucleoside triphosphate, consisting of a nitrogenous base (adenine), a ribose sugar, and three serially bonded phosphate groups

Question 60

ORGANELLE

Answer 60

Organelle is a subcellular structure that has one or more specific jobs to perform in the cell, much like an organ does in the body. Among the more important cell organelles are the nuclei, which store genetic information; mitochondria, which produce chemical energy; and ribosomes, which assemble proteins

Question 61

HOW DO PROTEINS MADE IN THE SOMA REACH THE TERMINAL

Answer 61

Molecules in vesicles attach
via kinesin to microtubules
and move toward the terminal.

Axoplasmic Transport - allows the impulse to travel down the axon, which can vary in terms of speed.

Question 62

KINESIN

Answer 62

Kinesins are biological motor proteins that are ATP-dependent and function to assist cells with the transport of molecules along microtubules.

*ATP - Adenosine triphosphate (ATP) is the source of energy for use and storage at the cellular level.

Question 63

AXOPLASMIC TRANSPORT

Answer 63

Transportation of proteins from soma to terminal.

Axoplasmic Transport - allows the impulse to travel down the axon, which can vary in terms of speed.

Question 64

GLIAL CELLS

Answer 64

Glial cells are the supporting cells of neurons:
*Astrocytes - most numerous, fill the space between neurons
-Regulates the chemical environment of the extracellular space
-Supplies nutrients, ions, oxygen from blood supply
-Synchronise neurons (wraps around many)
-Can be regulated by neurotransmitters!
*Oligodendrocytes - wrap cells in myelin (fatty insulation)
-Myelin sheath is interrupted by nodes of Ranvier (helps with propagation of electrical signal along the axon)
-This glial cell shares myelin with several axons
*Schwann cells (periphery) - similar to oligodendrocyte, but does not share myelin - each cell myelinates only a single axon
*Radial glia - guide neuron migration and axon growth (embryonic)
*Microglia - rid toxins

Question 65

GOGLI STAIN

Answer 65

Impregnates tissue with silver nitrate – see physical structure (the morphological heterogeneity) of neuron

Question 66

NEURONAL TRACES

Answer 66

Neuronal tracing, or neuron reconstruction is a technique used in neuroscience to determine the pathway of the neurites or neuronal processes, the axons an dendrites, of a neuron.