Nerves and Muscles Flashcards
______
- Structural and functional unit of nervous system
NEURON (NERVE CELL)
NEURON (NERVE CELL)
- ______ cells
Excitable
______
- Specialized cells that transmit chemical and electrical signals to facilitate communication between the brain and the body.
NEURON (NERVE CELL)
NEURON (NERVE CELL)
- Have ______ and all the ______ in cytoplasm.
nucleus, organelles
NEURON (NERVE CELL)
- More than ______ neurons in the human brain
10^12
NEURON (NERVE CELL)
Different from other cells by two ways:
Neuron has branches or processes called ______ and ______
axon, dendrites
NEURON (NERVE CELL)
Different from other cells by two ways:
Neuron does not have ______. So, it cannot undergo ______
centrosome, division
Neurons come in many different ______ and ______.
shapes, sizes
______
- Has the Ability to receive, process, integrate, and transmit information from external and internal sources to initiate most physiological behavior
NEURON (NERVE CELL)
______
- Produce sensation, thought, learning, movement, emotion, and many other processes.
NEURON (NERVE CELL)
NEURONS
Use ______ to transmit information within a single cell and ______ between cells.
electrical signals, chemical signals
At birth, the human brain consists of an estimated ______ neurons. Unlike other cells, neurons don’t ______ or ______. They are replaced by ______ only.
100 billion, reproduce, regenerate, neuroglia
BASIC COMPONENTS OF NEURON:
CELL BODY (SOMA/PERIKARYON)
DENDRITES
AXON
BASIC COMPONENTS OF NEURON:
______
- Contains the nucleus and DNA
CELL BODY (SOMA/PERIKARYON)
BASIC COMPONENTS OF NEURON:
______
- Multiple, short processes that extend outward from the cell body
DENDRITES
BASIC COMPONENTS OF NEURON:
______
- Contain Nissl bodies and neurofibrillae
DENDRITES
BASIC COMPONENTS OF NEURON:
DENDRITES
- “______” - receiving signals from other neurons via their synapses with axon terminals
Receptive Processes
BASIC COMPONENTS OF NEURON:
DENDRITES
Receptive Processes
- ______ - basophilic granules
Nissl Bodies
BASIC COMPONENTS OF NEURON:
DENDRITES
Receptive Processes
- ______ - consist of microfilament and microtubules
Neurofibrillae
BASIC COMPONENTS OF NEURON:
______
- Single, long process
AXON
BASIC COMPONENTS OF NEURON:
AXON
- Originates from a ______ of the cell body (______).
thickened area, axon hillock
BASIC COMPONENTS OF NEURON:
AXON
- The first portion of the axon is called the ______.
initial segment
BASIC COMPONENTS OF NEURON:
AXON
- Divides into ______ each ending in ______ that are also called ______.
presynaptic terminals, synaptic knobs, terminal buttons or boutons
BASIC COMPONENTS OF NEURON:
AXON
- ______ - cell membrane
Axolemma
BASIC COMPONENTS OF NEURON:
AXON
- ______ - cytoplasm
Axoplasm
BASIC COMPONENTS OF NEURON:
AXON
- ______ - A protein–lipid complex wrapped around the axon produced by Schwann cell
______ Neuron
______ Neuron
Myelin Sheath
Myelinated
Non-myelinated
BASIC COMPONENTS OF NEURON:
AXON
- ______ - gaps between two segments
Node of Ranvier
______
- Supporting cells present within the brain and spinal cord.
- Numerous
Neuroglia
NEUROGLIA TYPES:
MACROGLIA
MICROGLIA
NEUROGLIA TYPES:
______
- Large glial cells; ______ in origin.
- ______ (fibrous and protoplasmic astrocytes)
- ______.
MACROGLIA, ectodermal, Astrocytes, Oligodendrocytes
NEUROGLIA TYPES:
MICROGLIA
- Small glial cells; ______ in origin.
- More numerous in ______
- Act as ______
mesodermal, grey matter, phagocytes
Classification of Neurons
Based on functions:
SENSORY
MOTOR
Classification of Neurons
Based on functions:
SENSORY
- “______ nerve cells”
Afferent
Classification of Neurons
Based on functions:
______
- Carry sensory impulses from the periphery to the CNS.
SENSORY
Classification of Neurons
Based on functions:
______
- Short axon and long dendrites.
SENSORY
Classification of Neurons
Based on functions:
MOTOR
- “______ nerve cells”
Efferent
Classification of Neurons
Based on functions:
______
- Carry motor impulses from the CNS to the peripheral effector organs
MOTOR
Classification of Neurons
Based on functions:
______
- Very long axon and short dendrites.
MOTOR
Classification of Neurons
Based on the number of processes that emanate from their cell body:
Unipolar Cell
Bipolar Cell
Pseudounipolar Cell
Multipolar Cells
Classification of Neurons:
UNIPOLAR NEURONS
BIPOLAR NEURONS
PSEUDONIPOLAR CELLS
MULTIPOLAR CELLS
Classification of Neurons:
______
- One process, with different segments serves as receptive surface and releasing terminals.
UNIPOLAR NEURONS
Classification of Neurons:
______
- Two specialized processes:
______ that carries information to the cell
______ that transmits information from the cell.
BIPOLAR NEURONS, Dendrite, Axon
Classification of Neurons:
______
- Some sensory neurons are in a subclass of bipolar cells
PSEUDONIPOLAR CELLS
Classification of Neurons:
______
- A single process splits into two, function as axons:
One going to skin or muscle
Another to the spinal cord
PSEUDONIPOLAR CELLS
Classification of Neurons:
______
- One axon and many dendrites.
MULTIPOLAR CELLS
Classification of Neurons:
______
- e.g motor neurons, hippocampal pyramidal cells, and cerebellar Purkinje cells
MULTIPOLAR CELLS
NEURON
Four Important Zones:
(1) A dendritic zone
(2) Site where action potentials are generated
(3) Axonal process
(4) Nerve endings
NEURON
Four Important Zones:
______
- Multiple local potential changes generated by synaptic connections are integrated;
A dendritic zone
NEURON
Four Important Zones:
______
- Initial segment in spinal motor neurons, the initial node of Ranvier in cutaneous sensory neurons
Site where action potentials are generated
NEURON
Four Important Zones:
______
- Transmits propagated impulses to the nerve endings;
Axonal process
NEURON
Four Important Zones:
______
- Action potentials cause the release of synaptic transmitters.
Nerve endings
______
- Property of nerve fibers
EXCITABILITY
______
- Response by generating a nerve signal when it is stimulated by a stimulus (______, ______, ______ or ______)
EXCITABILITY, mechanical, thermal, chemical, electrical
______
- Production of action potential
EXCITABILITY
______
- An active, self-propagating process
CONDUCTION
______
- Impulse moves along the nerve at a constant amplitude and velocity normally transmitted (______) along the axon to its termination.
CONDUCTION, conducted
CONDUCTION
- Neurons produce ______ or ______ potentials reflecting changes in the conduction of ions across the cell membrane.
nonpropagated, propagated
CONDUCTION
______ (______) potentials (Based on ______)
- Synaptic, generator, or electrotonic potentials
Nonpropagated, local, location
CONDUCTION
______ action potentials
- Primary electrical response and main form of communication
Propagated
Neurons send messages ______.
electrochemically
Chemicals in the body are “______” called ______.
electrically-charged, ions
______ caused when different ions cross the neuron membrane.
Action potential
Important ions in the nervous system
- ______ and ______ (both have 1 positive charge,+)
Sodium, potassium
Important ions in the nervous system
- ______ (has 2 positive charges,++)
Calcium
Important ions in the nervous system
- ______ (has a negative charge,-)
Chloride
Nerve cells are surrounded by a semi-permeable membrane that ______ some ions to pass through and ______ the passage of other ions.
allows, blocks
Action Potential process:
- Resting state
- Depolarising phase
- Repolarising phase begins
- Repolarising phase continues
______ is crucial for: Nerve function, Skeletal muscle function, Smooth muscle function, Heart function
Potassium homeostasis
______
- High potassium level in blood
Hyperkalemia
______
- Often caused by: Impaired kidney excretion due to renal failure, Adrenal insufficiency, Certain medical conditions
Hyperkalemia
______
- Symptoms: Muscle pain, Weakness, Cardiac arrhythmias, Nausea
Hyperkalemia
______
- Can lead to cardiac arrest and death
Severe hyperkalemia
______
- Rare genetic disorder
Hyperkalemic periodic paralysis (HYPP)
______
- Causes muscle paralysis due to high potassium levels
Hyperkalemic periodic paralysis (HYPP)
______
- Muscle membrane potential shifts, inactivating sodium channels and preventing action potential generation
Hyperkalemic periodic paralysis (HYPP)
______
- Lower than normal potassium level in the bloodstream
Hypokalemia
______
- Commonly caused by: Increased excretion of potassium (K+), Shift of potassium from extracellular to intracellular space
Hypokalemia
______
- Other causes: Rare genetic disorders (Bartter syndrome, Gitelman syndrome), Cushing syndrome, Potassium-wasting diuretics, Diabetic ketoacidosis, Renal tubular acidosis, Familial
Hypokalemia
______
- symptoms: Weakness, Fatigue, Constipation, Muscle cramping, Palpitations
Hypokalemia
______
- Psychological symptoms: Depression, Psychosis
Hypokalemia
Severe hypokalemia (below ______ mEq/L)
2.5
______
- Can lead to cardiac rhythm issues: Bradycardia, Tachycardia, Premature beats, Atrial or ventricular fibrillation
Severe hypokalemia
______
- Axoplasm, the cytoplasm of the neurons is in constant ______. The ______ is vital to nerve cell functions, since movements of various materials occur through it.
AXOPLASMIC TRANSPORT, motion, axoplasmic transport
The axoplasmic transport is of two types:
Anterograde transport
Retrograde transport
The axoplasmic transport is of two types:
______, i.e. transport of materials away from the cell body. Some materials travel ______-______mm a day along the axoplasm. ______ play an important role in this form of transport.
Anterograde transport, 100, 400, Microtubules
The axoplasmic transport is of two types:
______, i.e. axoplasmic flow towards the cell body, may also carry tetanus toxin and neurotropic viruses (e.g. polio, herpes simplex and rabies) along the axon into the neuronal cell bodies in the CNS. It has also been employed by the neuroanatomists for charting out neural pathways.
Retrograde transport
An ______ (from Greek, ______), or nerve fiber is a long, slender projection of a nerve cell, or neuron, in vertebrates, that typically conducts electrical impulses known as action potentials away from the nerve cell body.
axon, axis
PARTS OF A NERVE FIBER:
Axon
Myelin Sheath
Nodes of Ranvier
Endoneurium
Perineurium
Epineurium
Axolemma
Axoplasm
PARTS OF A NERVE FIBER:
______: The central component of a nerve fiber, responsible for transmitting electrical impulses.
Axon
PARTS OF A NERVE FIBER:
______: A protective, insulating layer around the axon (found in ______ fibers) that increases the speed of nerve signal transmission. It is formed by ______ in the peripheral nervous system or ______ in the central nervous system
Myelin Sheath, myelinated, Schwann cells, oligodendrocytes
Some nerve fibers have no Myelin Sheath and are called ______.
Non-Myelinated Nerve Fibers
PARTS OF A NERVE FIBER:
______: Gaps in the myelin sheath along the axon, allowing for the rapid transmission of electrical signals via a process called ______.
Nodes of Ranvier, saltatory conduction
PARTS OF A NERVE FIBER:
______: A delicate connective tissue sheath surrounding each individual nerve fiber.
Endoneurium
PARTS OF A NERVE FIBER:
______, a layer of dense connective tissue that encloses a fascicle of nerve fibers, providing an effective barrier against penetration of the nerve fibers by foreign substances.
Perineurium
PARTS OF A NERVE FIBER:
______, a thick connective tissue sheath that surrounds and encloses a bundle of fascicles, forming the outermost covering of the nerve; it includes fatty tissue, blood vessels, and lymphatics.
Epineurium
PARTS OF A NERVE FIBER:
______: The outer membrane of the axon that maintains the electrical signal within the nerve fiber.
Axolemma
PARTS OF A NERVE FIBER:
______: The cytoplasm of the axon, which contains essential organelles and nutrients for axonal function and transport.
Axoplasm
______ fibers: Faster, insulated, used in rapid signal pathways.
Myelinated
______ fibers: Slower, lack insulation, used in slower or more steady processes.
Non-myelinated
MYELINATED NERVE FIBERS
Myelin Sheath: These fibers are wrapped in a fatty insulating layer called ______, produced by ______ in the peripheral nervous system (PNS) or ______ in the central nervous system (CNS).
myelin, Schwann cells, oligodendrocytes
MYELINATED NERVE FIBERS
Conduction Speed: The presence of myelin allows for ______ transmission of nerve impulses through a process called ______, where the electrical signal jumps from one ______ (gaps in the myelin sheath) to another.
faster, saltatory conduction, Node of Ranvier
