exam 1

Sensory receptors perform sensory function (detect changes)

Myelin is insulation around the axon

Myelin Formed by: Oligodendrocytes in CNS; Schwann cells in PNS

Axons with myelin appear white due to lipid content

Myelin significantly increases the speed of nerve conduction

A demyelinating disease is any condition that damages the protective coating on your nerve cells (myelin)

Guillain-Barré syndrome (GBS) is a rare autoimmune disorder where the body's immune system mistakenly attacks the peripheral nerves, which are the nerves outside the brain and spinal cord

Multiple sclerosis (MS) is a chronic, autoimmune disease that affects the central nervous system (brain and spinal cord)

Clusters of neuron cell bodies in the Peripheral Nervous System (PNS) are called ganglia, while in the Central Nervous System (CNS) they are called nuclei. 

Autonomic NS- regulates involuntary bodily processes, including heart rate, respiration, digestion, and pupil contraction; Operates automatically without conscious direction

Somatic NS- sensory information from sensory organs to the CNS and relays motor commands to muscles; controls voluntary movements

An impulse is transmitted from one neuron to another through a chemical process at a junction called a synapse

A subthreshold stimulus is a stimulus that is not strong enough to trigger an action potential in a cell

Excitatory postsynaptic potential (E PSP):

• Membrane change in which neurotransmitter opens Na+ Channels.

• Depolarizes membrane of postsynaptic neuron, as Na+ enters axon.

• Action potential in postsynaptic neuron becomes more likely

Inhibitory postsynaptic potential (I PSP):

• Membrane change in which neurotransmitter opens K+ channels (or Cl− channels).

• Hyperpolarizes membrane of postsynaptic neuron, as K+ leaves axon

• Action potential of postsynaptic neuron becomes less likely

Resting Membrane Potential- Electrical charge when there is no net ion movement across plasma membrane

Na+] High outside cell

[K+] High inside cell

Action potentials occur in excitable cells, including neurons, muscle cells, and some endocrine cells

An action potential is a rapid electrical signal generated by a neuron, where a sudden change in membrane potential occurs due to the movement of sodium (Na+) ions into the cell, followed by the movement of potassium (K+) ions out of the cell

Repolarization: Return to resting potential after action potential; occurs as K+ channels open & K+ ions rush out of cell; polarity returns

Depolarization: Change from negative to positive charge inside cell, making both sides of membrane positive

Once an axon membrane reaches threshold, the following sequence of events occurs: 

sodium channels rapidly open, causing a large influx of sodium ions, leading to depolarization of the membrane; then, sodium channels close while potassium channels open, allowing potassium ions to flow out, resulting in repolarization; finally, a brief hyperpolarization occurs before the membrane potential returns to its resting state; this process propagates down the axon as a wave, known as an action potential

Synapse: A site at which a neuron transmits a nerve impulse to another neuron

Neurotransmitters are removed from the synaptic cleft by diffusion, enzymatic degradation, or reuptake

Neurotransmitters that are considered modified amino acids include dopamine, norepinephrine, epinephrine (adrenaline), serotonin, and GABA (gamma-aminobutyric acid)

Neuroglial cells support neurons in the nervous system

Meninges is protective layers surrounding spinal cord and brain

Dura, a

An epidural hematoma is a collection of blood that forms between the skull and the dura mater, usually caused by a skull fracture that tears an underlying blood vessel

A subdural hematoma is a collection of blood between the inner layer of the skull (dura mater) and the surface of the brain

Cerebrospinal fluid (CSF) acts as a protective cushion around the brain and spinal cord, providing mechanical support, transporting nutrients, and removing waste products; it is secreted by the choroid plexus located within the ventricles of the brain and is reabsorbed back into the bloodstream through the arachnoid granulations in the dural venous sinuses

The correct order for the components of a reflex arc is: receptor, sensory neuron, spinal cord, motor neuron, effector (muscle)

A flexor-extensor reflex, also known as a "withdrawal reflex" or "crossed extensor/flexor reflex," is a protective spinal reflex where a limb quickly withdraws from a harmful stimulus (flexion) while the opposite limb simultaneously extends to maintain balance

A spinal tract is named based on its origin (the first part of the name) and where it terminates (the second part of the name)

Cauda equina is a collection of nerve roots at the end of the spinal cord that control movement and sensation in the legs and bladder

The hypothalamus is a small structure in the brain that controls many bodily functions, including hormone release, appetite, and sleep. It's located at the base of the brain, between the cerebral hemispheres, and in front of the thalamus

The pituitary gland is a small, pea-sized gland located at the base of the brain, situated in a bony cavity called the sella turcica, and functions as the "master gland" by producing hormones that control the activity of other glands throughout the body, regulating functions like growth, metabolism, sexual development, and stress response

The pineal gland is a small gland located deep within the center of the brain, in a region called the epithalamus, and its primary function is to produce the hormone melatonin, which helps regulate the body's circadian rhythm (sleep-wake cycle) by responding to light and darkness cues from the environment

The reticular formation is a network of neurons located within the brainstem that plays a crucial role in regulating consciousness, arousal, sleep-wake cycles, muscle tone, and various autonomic functions like breathing and heart rate

The primary motor area of the brain, also known as the motor cortex, is located in the frontal lobe, specifically in a region called the precentral gyrus; while the somatosensory cortex is situated in the parietal lobe, on the postcentral gyrus, just behind the central sulcus; Broca's area, crucial for speech production, is also found in the frontal lobe, typically in the left hemisphere. 

Frontal lobe: Responsible for higher-level cognitive functions like planning, decision-making, and personality. 

Parietal lobe: Processes sensory information from the body, including touch, temperature, and pain. 

Temporal lobe: Processes auditory information and plays a role in memory and language. 

Occipital lobe: Primarily responsible for visual processing

A cerebrovascular accident (CVA), also known as a stroke, is a medical condition where blood flow to the brain is interrupted, causing brain tissue damage

when sensory nerve fibers cross over, it means that the sensory information from one side of the body is processed by the opposite side of the brain, resulting in the left hemisphere of the brain interpreting sensations from the right side of the body and vice versa

The basal nuclei, also known as the basal ganglia, primarily function to initiate and control voluntary movements by selecting the appropriate motor actions, while the cerebellum is responsible for fine-tuning and coordinating movements, ensuring smooth and precise execution, and maintaining balance;

Parkinson's disease is a progressive neurodegenerative disorder that occurs when nerve cells in the brain die or break down. This loss of neurons, particularly in the basal ganglia, leads to a decline in dopamine production and irregular brain activity

In the spinal cord, the Anterior root contains motor neurons carrying signals away from the central nervous system (CNS) to muscles, while the Posterior root contains sensory neurons carrying signals towards the CNS, with the cell bodies of these sensory neurons located in the Posterior root ganglion; the Anterior gray horn houses the cell bodies of motor neurons that send axons out through the anterior root, whereas the Posterior gray horn receives sensory information from the posterior root and contains the cell bodies of second-order sensory neuron

A dermatome is a specific area of skin on the body that is supplied by a single spinal nerve, essentially mapping out the sensory distribution of each nerve root; while referred pain is when pain is felt in a different location than where the injury or source of pain actually is

All preganglionic fibers (both parasympathetic and sympathetic) release acetylcholine, while most postganglionic parasympathetic fibers release acetylcholine, and most postganglionic sympathetic fibers release norepinephrine (with a few exceptions)

The twelve cranial nerves, in numerical order, are: 

Olfactory nerve (I)

Optic nerve (II)

Oculomotor nerve (III)

Trochlear nerve (IV)

Trigeminal nerve (V)

Abducens nerve (VI)

Facial nerve (VII)

Vestibulocochlear nerve (VIII)

Glossopharyngeal nerve (IX)

Vagus nerve (X)

Accessory nerve (XI)

Hypoglossal nerve (XII) 

The limbic system is the part of the brain involved in our behavioural and emotional responses, especially when it comes to behaviours we need for survival

A receptor potential is an electrical signal generated by a sensory receptor cell in response to a stimulus

Olfactory receptors (ORs) are proteins in the nasal epithelium that detect odors and are responsible for the sense of smell

Baroreceptors:

Sensory receptors that detect changes in blood pressure, primarily located in the walls of the carotid arteries and aorta, sending signals to the brain to regulate blood pressure levels. 

Nociceptors:

Sensory receptors that detect pain stimuli, signaling potential tissue damage and triggering a pain response in the body. 

Thermoreceptors:

Sensory receptors responsible for detecting changes in temperature, allowing the body to sense heat and cold. 

Proprioceptors:

Sensory receptors located within muscles, tendons, and joints that provide information about body position and movement, allowing for coordinated muscle activity and balance

The muscle spindles and golgi tendon organs are proprioceptive sensory organs, which detect the change in muscle length, posture, and motion of body parts located in muscle tendons

The five primary taste sensations are sweet, sour, salty, bitter, and umami

Refraction of light occurs when light travels from one transparent medium to another with a different density, causing the light to bend or change direction due to a change in its speed as it enters the new medium

In the eye, the cornea is the primary structure responsible for refracting light as it enters the eye, bending the light rays significantly, while the lens further refines the focus by also refracting light, and the aqueous humor plays a smaller role in light refraction by acting as a transparent medium that allows light to pass through with minimal bending

At the optic chiasm, the nasal retinal fibers from each optic nerve decussate (crossover) into the contralateral optic tract

The structure of the semicircular canals suggests how they detect the angular accelerations that arise through rotation of the head

A cataract is a clouding of the eye's natural lens, which is located behind the pupil and helps focus light on the retina

With age the lens becomes yellowed, less flexible, and slightly cloudy leading to the development of cataracts

Sound waves enter the outer ear and travel through a narrow passageway called the ear canal, which leads to the eardrum

It begins at the retina and terminates at the primary visual cortex

conductive hearing loss is caused by issues in the outer or middle ear, while sensorineural hearing loss is caused by issues in the inner ear or auditory nerve

Nearsightedness (myopia) makes far-away objects look blurry. Farsightedness (hyperopia) makes nearby objects look blurry. Astigmatism can make far-away and nearby objects look blurry or distorted. Presbyopia makes it hard for middle-aged and older adults to see things up close.

The auditory tube, also known as the Eustachian tube, is a tube that connects the middle ear to the throat and nose.

The fovea centralis, or fovea, is a small depression within the neurosensory retina where visual acuity is the highest