Overview of Brain Structure and Function

Cerebrum

higher-order functions such as thought, memory, and voluntary movement.

Cerebellum

coordinates movement and maintains balance.

Brainstem

controls vital autonomic functions, including heart rate, blood pressure, and breathing.

Midbrain

processing visual and auditory information, as well as motor control.

Pons

relays signals between different parts of the brain and is involved in sleep and respiration.

Medulla oblongata

regulates autonomic functions such as heart rate, blood pressure, and respiration.

Thalamus

acts as a relay station for sensory information.

Hypothalamus

maintains homeostasis and regulates endocrine functions.

Pineal gland (Epithalamus)

endocrine gland that produces melatonin and regulates circadian rhythms.

Longitudinal fissure

deep groove that divides the left and right cerebral hemispheres.

Transverse cerebral fissure

groove that separates the cerebrum from the cerebellum.

Falx cerebri, falx cerebelli, tentorium cerebelli

Extensions of the dura mater that provide support and protection to the brain.

Gray matter

contains the cortex and nuclei, primarily composed of neuronal cell bodies.

inner spinal cord

White matter

consists of myelinated axons, forming tracts that connect different brain regions.

outer spinal cord

Astrocytes and neurons

primary cell types found in gray matter.

Oligodendrocytes

Cells responsible for producing myelin in the central nervous system.

Cerebral vesicle development

neural plate transforms into a tube and develops into primary brain vesicles.

Primary vesicles

three initial brain divisions: forebrain, midbrain, and hindbrain.

Frontal lobe functions

areas responsible for higher cognitive functions such as decision-making and motor control.

Parietal lobe function

processing sensory information related to touch and spatial awareness.

Temporal lobe functions

Responsible for auditory processing and language comprehension.

Occipital lobe function

dedicated to visual processing.

Insula functions

taste perception and visceral sensations.

Broca's aphasia

nonfluent speech, where comprehension is intact but speech production is impaired.

Wernicke's aphasia

speak fluently but produce nonsensical language and have difficulty understanding speech.

CSF functions

Provides protection, buoyancy, and chemical stability to the brain.

CSF production location

Produced in the choroid plexus by ependymal cells.

CSF reabsorption location

Absorbed into the superior sagittal sinus via arachnoid villi.

CSF flow pathway

route taken by cerebrospinal fluid through the ventricles and into the subarachnoid space.

Blood‑Brain Barrier components

Formed by tight junctions between endothelial cells and astrocytes, protecting the brain from harmful substances.

BBB‑permeable substances

Includes glucose, oxygen, carbon dioxide, and alcohol.

Limbic system structures

Comprises the hippocampus, amygdala, and cingulate gyrus, involved in emotion and memory.

Limbic system functions

emotional responses, memory formation, and motivation.

Reticular formation functions

Regulates arousal, sleep, attention, and muscle tone.

Reticular damage effect

Can lead to coma or altered states of consciousness.

Association tracts

Connect different areas within the same hemisphere of the brain.

Commissural tracts

Connect left and right cerebral hemispheres, such as the corpus callosum.

Projection tracts

Connect the cerebrum to lower brain centers and the spinal cord.

Upper motor neurons

Neurons that transmit signals from the cortex to the spinal cord.

Lower motor neurons

Neurons that carry signals from the spinal cord to muscles.

Short‑term memory location

Primarily located in the prefrontal cortex.

Declarative long‑term memory location

Stored in the hippocampus.

Procedural memory location

Located in the cerebellum, responsible for motor skills.

Alpha waves

Brain waves associated with a relaxed, awake state.

Beta waves

Brain waves that occur when an individual is alert and awake.

Theta waves

Brain waves present during light sleep.

Delta waves

Brain waves associated with deep sleep.

REM sleep characteristics

Includes dreaming, muscle paralysis, and memory consolidation.

ANS divisions

divided into sympathetic (fight or flight) and parasympathetic (rest and digest) divisions.

Sympathetic origin

Originates from the thoracolumbar region of the spinal cord.

Parasympathetic origin

Originates from the craniosacral region.

Reflex arc pathway

sequence of components involved in a reflex action.

Preganglionic neurotransmitter

Acetylcholine (ACh) is released by preganglionic neurons.

Postganglionic sympathetic neurotransmitter

Norepinephrine (NE) is released by postganglionic sympathetic neurons.

Postganglionic parasympathetic neurotransmitter

Acetylcholine (ACh) is released by postganglionic parasympathetic neurons.

Cholinergic receptor types

Includes nicotinic and muscarinic receptors that respond to acetylcholine.

Adrenergic receptors

Receptors that respond to norepinephrine and epinephrine.

Adrenal medulla secretion

Releases epinephrine and norepinephrine into the bloodstream.

Receptor potential

A local electrical change in a sensory receptor in response to a stimulus.

Sensation

The conscious perception of a stimulus by the nervous system.

Receptor modalities

Include thermoreceptors, mechanoreceptors, chemoreceptors, and nociceptors.

Exteroceptors

Sensory receptors that detect external stimuli.

Proprioceptors

Receptors that provide information about body position and movement.

Phasic receptors

Receptors that adapt quickly to a stimulus, such as those for smell.

Tonic receptors

Receptors that adapt slowly and continue to respond to a stimulus, such as pain receptors.

Natural analgesics

Substances like endorphins and enkephalins that reduce pain perception.

Five basic tastes

Sweet, salty, sour, bitter, and umami are the primary taste modalities.

Olfactory pathway

The route taken by olfactory signals from the olfactory nerve to the cortex.

Outer ear structures

Includes the auricle and auditory canal.

Middle ear structures

Comprises the tympanic membrane, ossicles, and auditory tube.

Inner ear structures

Contains the cochlea for hearing and semicircular ducts for balance.

Equilibrium pathway

The pathway that transmits balance information from hair cells to the brain.

Retina layers

Consists of photoreceptors, bipolar cells, and ganglion cells.

Visible light range

The spectrum of light that humans can see, approximately 400-700 nm.

Optical structures

Includes the cornea and lens, which focus light onto the retina.

Neural vision structures

Comprises the retina and optic nerve, involved in vision processing.

Accommodation

The process by which the lens changes shape to focus on objects at different distances.

Rods function

Specialized for night vision and peripheral vision, but do not detect color.

Cones function

Responsible for color vision and detail in bright light.