Brain regulation, Coordination & protection

thalamus

Relays most sensory information to the cerebral cortex and helps regulate attention and awareness. doesn’t include smell.

Hypothalamus

Maintains homeostasis by regulating temperature, hunger, thirst,sleep and autonomic nervous system and pituitary hormone release.

epithalamus

contains the pineal gland, which secretes melatonin to help regulate circadian rhythms

Amygdala

process emotional significance, especially fear and threats

hippocampus

forms new declarative memories

hypothalamus

coordinates bodily and hormonal responses associated with emotions

midbrain

visual and auditory reflexes, eye movements and movement regulation

Pons

Helps adjust breathing rate and depth

Medulla oblongata

Regulates heart rate, blood vessel activity, basic breathing rhythm and protective reflexes

reticular formation

helps maintain wakefulness, alertness, consciousness, and sensory attention

basic nuclei

help select desired movements and suppress unwanted movements (movement selection)

cerebellum

refines movements, timing, balance , posture, and motor learning

( movement correction)

parkinsons disease

associated with basal nuclei circuits

cerebellar ataxia

involves impaired coordination and balance

meninges

three protective membranes surrounding the brain

Dura mater, arachnoid mater, and pia mater

Dura matter

tough outer layer of brain protection

Arachnoid mater

middle layer of brain protection: middle layer, CSF circulates beneath it in the subarachnoid space

Pia matter

Delicate inner layer that follows the brains surface in brain protection

cerebrospinal fluid (CSF)

provides Buoyancy, reducing the brains effective weight

helps cushion the brain and spinal cord

helps maintain chemical stability

Hydrocephalus

CSF accumulates because circulation is blocked or reabsorption is impaired. This can enlarge the ventricles and increase intracranial pressure (ICP).

inter-cranial pressure

The skull is rigid, so swelling, bleeding, or excess CSF can raise pressure, reduce blood flow, and decrease oxygen delivery to brain tissue.

Blood - Brain barriers

• Tight junctions: Restrict movement between capillary endothelial cells.

• Glucose: Enters using transport proteins.

• Oxygen and carbon dioxide: Diffuse readily.

• Astrocytes: Help maintain the barrier.

• Some medications, toxins, and pathogens are restricted from entering.

BBB ( blood brain barrier )

selectively controls which substances enter brain tissue

Stroke (CVA)

Blood supply is interrupted or bleeding occurs within the brain, potentially damaging brain tissue.

TIA

A A transient ischemic attack is a brief episode of disrupted blood flow.

• Symptoms depend on the affected brain region. Examples include difficulty swallowing, weakness, dizziness, abnormal breathing, and poor coordination.

The hypothalamus coordinates responses that keep the body's internal environment stable this includes

Body temperature: Activates heat-loss or heat-

conserving responses

• Water balance: Regulates thirst and ADH release

• Autonomic control: Influences heart rate, blood

pressure, and digestion

• Endocrine control: Regulates pituitary hormone

secretion

• Biological rhythms: Helps regulate sleep–wake

cycles and hunger

Limbic system

includes the amygdala, hippocampus and hypothalamus and is focused on linking emotion, memory and physiology

Midbrain

connects sensory information and movement

Visual reflexes ( superioir conculi) , adutitory reflexes (inferior conculi), motor regulation , eye movements using midbrain nuclei.

Arousal & wakefulness:

Ascending pathways help

maintain alertness and consciousness.

Sensory filtering:

Helps regulate which incoming

stimuli receive attention.

Motor & autonomic regulation

Descending pathways

contribute to posture, muscle tone, and autonomic

functions.

Basal Nuclei

Selecting and regulating

movement

• Help initiate desired

movements

• Suppress unwanted movements

• Contribute to automatic,

learned motor patterns

• Clinical example:

• Parkinson's disease

cerebellum

Refining and correcting

movement

• Coordinates timing and

precision

• Maintains balance and

posture

• Corrects movement errors

• Clinical example:

• Cerebellar ataxia

Hydrocephalus:

When CSF Accumulates

Blocked circulation or impaired

reabsorption causes CSF to accumulate; ventricles enlarge, potentially

increasing intracranial pressure (ICP),Headache, nausea/vomiting, and

changes in mental status

Intracranial Pressure (ICP):

Limited Space, Serious Consequences

Swelling, bleeding, or CSF accumulation, increased intracranial pressure (ICP) , reduced blood flow, Decreased oxygen delivary and nueronal dysfunction

Movement and coordination

Basal nuclei regulate movement selection; cerebellum refines coordination, precision and balance

Regulation & Homeostasis

Hypothalamus regulates internal conditions; brainstem controlls vital functions like breathing and blood pressure

Protection and stability

Meninges provide physical protection,CSF cushions the CNS , and the blood-brain barrier selectively regulates entry of substances

Two cerebral hemispheres

separated by the longitudinal fissures with surface folds that increase the area for the cerebral cortex. the two hemispheres are connected by the corpus callosum.

frontal lobe

Voluntary movement, planning, decision-

making, personality, speech production

parietal lobe

Processing touch, pressure, temperature,

pain, and spatial awareness

temporal lobe

Hearing, memory, language comprehension

occipital lobe

visual processing

Insula

Taste, visceral sensation, and integration of

internal body signals

Motor areas

produce movement and control voluntary skeletal movements.

sensory areas

Receive information

Allow conscious awareness of sensations such as touch,

vision, and hearing.

Association areas

Interpret and integrate

Combine information with memories and experiences to

guide behavior.

Motor homunculus

Larger cortical areas are devoted to body regions requiring precise, fine

movements.

Sensory homunculus

Larger cortical areas are devoted to body regions with greater sensory

sensitivity.

Sensory association areas

Interpret sensory input, allowing us to

recognize what we see, hear, or feel.

Motor association areas (premotor cortex)

Plan and coordinate learned, skilled

movements.

Prefrontal cortex

Supports judgment, planning, decision-

making, and working memory

Brocas’s area

speech production

Usually in the left frontal

lobe

•Helps plan the movements

needed for speech

•Damage: slow, effortful

speech with relatively

preserved comprehension

Wernicke’s area

Language comprehension

•Usually in the left posterior

temporal region

•Important for understanding

language

•Damage: fluent but often

nonsensical speech with

impaired comprehension

Association fibers

Connect cortical regions within the same hemisphere

Commissural fibers

connect the left nd right hemispheres

Projection Fibers

Connect the cerebral cortex with

deeper brain regions and the

spinal cord

Gray matter

process information

White matter

provides pathways for communication