Nervous System
What is the function of connective tissue in the nervous system?
Connective tissue provides support and structure for nervous tissue. It also helps to protect the nervous system from damage.
Can some of the cells in nervous tissue be regenerated if they are damaged?
Some of the cells in nervous tissue, such as neuroglial cells, can be regenerated if they are damaged. However, neurons cannot be regenerated. This is why damage to the nervous system can be so devastating.
What are some of the supportive functions of neuroglial cells?
Providing structural support Supplying nutrients to neurons Removing waste products from neurons Protecting neurons from damage Helping to form the myelin sheath
What are the three main functional parts of a typical neuron,
Receptive region, conducting region, secretory region
What does the spinal cord enable between the brain and the body, and what independent functions can it perform?
The spinal cord facilitates communication between the brain and the body below the head and neck, and it can also carry out certain functions independently.
How many neurons does the spinal cord have compared to the brain?
The spinal cord has about 100 million neurons, fewer than the brain's 100 billion.
What is the function of satellite cells?
Satellite cells provide structural support to neurons in the PNS. They also regulate the chemical environment around neurons and play a role in neuronal regeneration after injury.
What is the function of Schwann cells?
Schwann cells produce myelin sheaths around axons in the PNS. They also play a role in supporting axon regeneration after injury.
What is the function of dendrites in a neuron?
Sense incoming signals, convert to electrical signal, transmit signal to the cell body
Sensory stimuli are first detected by structures of the PNS called ______?
Sensory receptors
Similar to epithelial tissue, nervous tissue is highly cellular. What percentage of nervous tissue volume is composed of cells?
80% of nervous tissue volume consists of cells.
Conductivity
A material's ability to allow heat or electric charges to flow. Similar to how an electrical impulse is conducted through a copper wire, electrical changes across the plasma membrane of a neuron don't stay in one place. Instead, they are rapidly conducted along the entire length of the membrane.
What is the composition of a nerve, and what elements surround it?
A nerve is composed of a bundle of long neuron axons. It is surrounded by connective tissue sheaths and packaged together with blood vessels.
What are the six main types of neuroglia?
Astrocytes, Oligodendrocytes, Microglia, Schwann cells, Ependymal cells, Satellite cells
Visceral motor division can also be called _____?
Autonomic Nervous system
How diverse are sensory receptors, and what is an example of their range?
Sensory receptors vary from small skin neurons sensing temperature to complex muscle receptors detecting stretch.
What organelles are present in axons, and which ones are absent?
Axons contain mitochondria, intermediate filaments, vesicles, and lysosomes, but they lack protein-making organelles such as ribosomes or Golgi apparatus.
How are nerves classified?
Based on their origin or destination 1) cranial nerves go to or come from the brain, 2) spinal nerves go to or come from the spinal cord.
What are the branches extending from some axons called?
Branches extending from some axons are called axon collaterals.
Name two structural division of nervous system?
Central Nervous System and Peripheral Nervous system
Where are sensory stimuli first detected, and what are the structures responsible for this in the PNS?
Sensory stimuli are first detected by structures called sensory receptors in the PNS.
What are the three types of functions in the nervous system?
Sensory, integrative, and motor functions.
Cell body is also known as
Soma
Through which vertebral foramen does the spinal cord pass, and where does it continue?
The spinal cord passes through the first cervical vertebra and continues to the first or second lumbar vertebra.
How many pairs of cranial nerves and spinal nerves are there? Back:
There are 12 pairs of cranial nerves and 31 pairs of spinal nerves.
How many types of neuroglia are there, and where are they found?
There are six different types of neuroglia in the nervous system, with four in the Central Nervous System (CNS) and two in the Peripheral Nervous System (PNS).
What is the role of neurons in the CNS with sensory input?
They integrate sensory inputs to form a comprehensive picture for potential responses.
Neurons are the excitable cell type responsible for sending and receiving signals in the form of ____________?
action potentials
Motor function ?
actions performed in response to integration
Where does the brain merge with the spinal cord in the central nervous system?
at the foramen magnum.
The conducting region of the neuron is the __________.
axon
What is the organ of the central nervous system enclosed completely by the skull?
brain
CNS is made up of ________ and _________
brain and spinal cord
What are the organs of the CNS?
brain and spinal cord
What do integrative functions in the nervous system involve?
detected sensory stimuli and determine an appropriate response.
What is the autonomic nervous system (ANS)?
division of the peripheral nervous system division of the peripheral nervous system
ANS control involuntary function of the body such as ______?
heart rate, blood pressure, digestion, and respiration.
Where do the majority of biosynthetic processes of a neuron occur?
in the central cell body.
What is the function of the myelin sheath?
increase speed of electrical signals
What does the somatic sensory division include besides muscles and skin signals?
it includes neurons transmitting signals from vision, hearing, taste, smell, and balance organs
What is the most conspicuous part of a neuron?
its large cell body, also known as the soma.
What is the function of astrocytes?
maintain blood-brain barrier; provide structural support; regulate ion, nutrient, and dissolved gas concentrations; absorb and recycle neurotransmitters; form scar tissue after injury
What maintains the characteristic shape of the cell body in a neuron?
maintained by the neuronal cytoskeleton, which is composed largely of intermediate filaments.
What is electrophysiology?
the study of the electrical activity of cells
ANS carries neurons to _____?
thoracic and abdominal viscera
roles of motor neurons
to carry out the motor functions of the nervous system.
What are the key functions of the somatic motor division?
to enable voluntary movement, maintain posture and balance, and control reflexes.
What is the function of the myelin sheath?
to protect the neuron, provide insulation, and increase the speed of impulse transmission
What are ion channels?
proteins that create specific pathways for charged molecules. Ion channels are proteins embedded in the plasma membrane that allow specific ions to pass through the membrane. They play a crucial role in generating and regulating electrical signals in neurons.
What are the two types of axonal transport
slow axonal transport and fast axonal transport
These are called ______?
special sensory division
What is the composition of myelin?
t contains phospholipids, other lipids such as cholesterol, and proteins. In addition, myelin contains lipids unique to Schwann cells and oligodendrocytes.
Is the somatic motor division under voluntary or involuntary control?
voluntary control
What is another name for the somatic motor division?
voluntary motor division.
PNS sensory receptor is divided into ???
1) Somatic sensory division 2) Visceral Sensory division
PNS motor division is further divided into ?
1) somatic motor division 2) Visceral motor division
What are the functions of the ANS?
1. Controls all involuntary activities such as cardiovascular, respiratory, digestive, endocrine, urinary and reproductive systems. 2. Fight or flight response. (Sympathetic System) 3. Rest and Digest (Parasympathetic System)
How many cells, called neurons, does the brain consist of?
100 billion cells called neurons (NOOR-onz) or nerve cells.
What is the resting membrane potential?
Difference in electrical charge across the membrane at rest. In neurons, the resting membrane potential is typically around -70 millivolts (mV).
From where does an axon typically arise, and what is its structure?
Each axon arises from an area of the cell body called the Axon hillock and tapers to form the slender axon, often wrapped in the insulating myelin sheath.
What is the function of ependymal cells?
Ependymal cells produce cerebrospinal fluid (CSF), which acts as a shock absorber and provides nutrients to the CNS.
What is the function of epithelial tissue in the nervous system?
Epithelial tissue lines the surfaces of the brain and spinal cord. It helps to protect these organs from infection and injury.
How is sensory input gathered?
Gathered by the sensory (afferent) division of the PNS
What does sensory function involve?
Gathering information about internal and external environments.
What is the difference between graded potentials and action potentials
Graded potentials are local changes in the membrane potential that decay over time and distance. They cannot travel the entire length of an axon. Action potentials, on the other hand, are all-or-nothing events that cause a rapid depolarization of the membrane potential. They can travel the entire length of an axon, transmitting signals over long distances.
Besides intermediate filaments, what else does the neuronal cytoskeleton contain?
In addition to intermediate filaments, the neuronal cytoskeleton contains microtubules that provide structural support and serve as a means for transporting chemicals between the cell body and the axon.
What structures do intermediate filaments bundle together to form in the neuronal cytoskeleton?
Intermediate filaments in the neuronal cytoskeleton bundle together to form larger structures called neurofibrils.
The ans is voluntary or involuntary control of the body?
Involuntary
What does the somatic sensory division of the PNS do?
It carries signals from skeletal muscles, bones, joints, and skin.
What does the visceral sensory division include, and which signals does it transmit?
It includes neurons transmitting signals from organs like the heart, lungs, stomach, intestines, kidneys, and urinary bladder.
What is the function of microglia?
Microglia are immune cells that scavenge debris, remove pathogens, and promote repair after injury or disease. They also play a role in neural development and synaptic pruning.
Why are mitochondria found in large numbers in the cell body of a neuron?
Mitochondria are found in large numbers in the cell body of a neuron, indicating the high metabolic demands of the neuron.
How does motor output from the brain and spinal cord reach muscles or glands, and what does it control?
Motor output travels via cranial and spinal nerves of the PNS to control muscle contraction or gland secretion.
What are the unique lipids found in myelin?
Myelin contains lipids unique to Schwann cells and oligodendrocytes. These lipids play a role in maintaining the stability and permeability of the myelin sheath.
What type of tissue is the majority of the material in nervous system organs?
Nervous tissue
Where do neurofibrils extend in a neuron?
Neurofibrils extend out into the dendrites and axon of the neuron.
What functions do neuroglia perform in the nervous system?
Neuroglia perform functions such as maintaining the environment around neurons, protecting them, and assisting in their proper functioning. Unlike neurons, neuroglia retain the ability to divide and fill in gaps left when neurons die.
What are neuroglia, and why were they originally named "neuroglial cells"?
Neuroglia, or neuroglial cells, were originally named for the idea that they "glued together" neurons, as the word root "glia" means "glue." However, it is now recognized that neuroglia serve many functions, including maintaining the environment around neurons, protecting them, and assisting in their proper functioning
Why are neurons considered long-lived cells?
Neurons are long-lived cells because, given adequate nutrition and oxygen in a supportive environment, some neurons can easily survive the entire lifespan of an organism.
Which cell type is most obvious when looking at a micrograph of nervous tissue?
Neurons are the most obvious cell type in nervous tissue. They are the excitable cells that are responsible for sending and receiving signals.
What does it mean when neurons are described as "amitotic"?
Neurons being "amitotic" means that, at a certain point in development, they lose their centrioles and, as a result, lack the ability to undergo mitosis.
What are the two key properties that neurons share with skeletal muscle fibers?
Neurons share two key properties with skeletal muscle fibers: excitability and conductivity.
What is the function of oligodendrocytes?
Oligodendrocytes are responsible for producing myelin, which insulates axons and speeds up the transmission of electrical signals. They also play a role in supporting axon growth and repair. in short == produce myelin (myelinate axons) in CNS
What organelles involved in protein synthesis are present in the cell body of a neuron?
Organelles involved in protein synthesis, including the Golgi apparatus and one or more prominent nucleoli, are present in the cell body of a neuron.
where is integration performed?
Performed by the CNS, mostly by the brain.
What is the role of an axon in a neuron?
The axon is the long "arm" of a neuron that generally carries electrical signals away from the cell body.
Which part of the neuron serves as the conducting region, and what is its role?
The axon serves as the conducting region of the neuron, transmitting signals from the cell body to other parts of the neuron.
Neuron or nerve cell ?
The basic unit of the nervous system, consists of a cell body, nucleus, dendrites, and axon. enable everything from the regulation of breathing and the processing of algebra to performing in the creative arts.
Why is the cell body of a neuron considered the most metabolically active part?
The cell body of a neuron is the most metabolically active part because it is responsible for maintaining the cytoplasmic volume of the neuron and manufacturing all the proteins the neuron needs.
What organelles are present in the cytoplasm of dendrites?
The cytoplasm of dendrites contains most of the same organelles as the cell body, including mitochondria, ribosomes, and smooth endoplasmic reticulum.
What organelles are present in the cytoplasm of the cell body of a neuron?
The cytoplasm of the cell body of a neuron includes lysosomes, smooth endoplasmic reticulum (ER), and other organelles found in most cells.
What is the diameter range of a neuron's cell body (soma)?
The diameter of a neuron's cell body (soma) ranges from 5 to 100 μm.
What feature of most neurons gives them a significant receptive surface area?
The extensively forked "dendritic trees" of most neurons give them a huge receptive surface area.
What is the termination point of the fine branches known as Telodendria?
The fine branches known as Telodendria terminate in axon terminals or synaptic knobs, which communicate with a target cell.
How does the specialized form of each type of neuroglial cell relate to its function?
The form of each type of neuroglial cell is specialized for its function, illustrating the Structure-Function Core Principle in biology
What reflects the high level of biosynthetic activity in the cell body of a neuron?
The high level of biosynthetic activity in the cell body of a neuron is reflected in the composition of organelles, including the abundance of free ribosomes and rough endoplasmic reticulum (RER), forming dark-staining clusters known as Nissl bodies.
What is the primary component of the peripheral nervous system, and what is its function?
The peripheral nervous system is mainly composed of nerves, which carry signals to and from the central nervous system.
What envelops the axon, and what are the components of its cytoplasm called?
The plasma membrane that envelops the axon is called the axolemma, and its cytoplasm is known as axoplasm.
What is the secretory region of a neuron, and where is it located?
The secretory region of a neuron is formed by the axon terminals. In this region, chemicals are secreted, triggering changes in the target cells.
What is the myelin sheath?
This term refers to a type of tissue formed by specialized cells called schwann cells.
How is sensory input carried from sensory receptors to the spinal cord and brain?
Through cranial and spinal nerves of the PNS.
How is an axon traditionally defined, and what criteria are used to define it now?
Traditionally, an axon was defined as a process that carries a signal away from the cell body. However, new criteria consider axons as processes capable of generating and conducting action potentials.
What is the significance of neuroglia retaining their ability to divide?
Unlike neurons, which are mostly amitotic, neuroglia retain the ability to divide, filling in gaps left when neurons die. This ability contributes to their role in supporting and maintaining the nervous system.
How does the resting membrane potential change when a neuron is stimulated?
When a neuron is stimulated, the flow of ions across the plasma membrane changes, causing the resting membrane potential to fluctuate. These fluctuations in the membrane potential are called graded potentials or local potentials
What is the somatic motor division?
a division of the nervous system that transmits signals to skeletal muscles.
Excitability (irritability)
ability to receive and respond to stimuli. Neurons are excitable, meaning they can respond to various stimuli, including chemical signals, local electrical signals, and mechanical deformation. These stimuli generate electrical changes across the plasma membrane of the neuron.
How is motor output performed in the nervous system?
carried out by the motor (efferent) division of the PNS.
What are the three main parts of a neuron?
cell body, dendrites, axon
A nerve is surrounded by which type of connective tissue?
connective tissue sheaths.
What does the PNS motor division consist of
consists of motor neurons,
What type of muscles does the somatic motor division control?
controls skeletal muscles, which are responsible for voluntary movement.
PNS is made up of
cranial and spinal nerves
What are the organs of the PNS?
nerves and cranial
What are the two main types of cells found in nervous tissue?
neurons and glial cells
Do dendrites generate or conduct action potentials?
no
Define effectors
organs that carry out the effects of the nervous system. maybe muscle or gland especifically
How does the resting membrane potential arise?
· Na+K+ATPase - 3 Na+ move out, 2 K+ move in. · K+ leak channels - K+ flows out. Ion channels play a crucial role in maintaining the resting membrane potential by allowing ions to move across the plasma membrane in a controlled manner. The selective permeability of ion channels allows for the maintenance of the ion concentration gradients that establish the resting membrane potential.
