Human Anatomy Mike Aaron Ch 15

Connective Tissues overing the brain

the skull & the cranial meninges

Cranial Meninges

the Dura Mater, the Arachnoid Layer, and the Pia Mater

Dura Mater

outer layer forming protective bag over brain ; composed of dense irregular connective tissue ; Epidural Space above

Epidural Space

space between the Skull & Dura Mater ; contains adipose tissue serving as a padding for the brain

Arachnoid Layer

middle layer ; collagen and elastic fibers appearing as spider web ; avascular ; Subdural Space above

Subdural Space

space between the dura mater and arachnoid layer filled with interstitial fluid

Pia Mater

innermost layer ; transparent layer of connective tissue that covers the brain and spinal cord ; highly vascular ; Subarachnoid Space above

Subarachnoid Space

space between the arachnoid layer and Pia mater containing cerebrospinal fluid

Meningitis

inflammation of the meninges; can be bacterial or viral

Cerebrospinal Fluid (CSF)

circulates through the subarachnoid space ; within the brain, it circulates through ventricles (open spaces in brain)

Functions of CSF

Buoyancy, Protection, Chemical Stability

the Choroid Plexus

network of capillaries in the walls of ventricles of the brain ; ependymal cells cover the capillaries and secrete CSF

Hydrocephalus

disorder in which excess CSF accumulates in ventricles of brain

Cerebral Aqueduct

what the CSF travels to nourish the cerebellum and brain stem

Central Canal

what the CSF travels to nourish the Spinal Cord

Blood-Brain Barrier (BBB)

prevents the passage of certain compounds into the brain

BBB is formed by…

tight attachment of ependymal cells & astrocytes in capillaries

Principal parts of the brain

the Brain Stem, Cerebellum, Diencephalon, & Cerebrum

Brain Stem

connects the spinal cord to the diencephalon ; consists of the medulla oblongata, pons, midbrain, & the reticular formation

Medulla Oblongata

begins at the foramen magnum and extends upwards towards the pons ; contains ascending and descending tracts connecting the spinal cord to the brain

Major parts of the Medulla

the Pyramids, Nucleus Gracilis & Nucleus Cuneatus, Cardiovascular Center, Medullary Rhythmicity Area, Vasomotor Center, & the Olive

the Pyramids

bulges on the anterior portion of the medulla contains motor tracts that pass from the cerebrum to the spinal cord

Decussation of Pyramids

region on the medulla where nerves from the pyramids cross over each other ; neurons on the left side of the medulla control effectors on the right side of the body and vice versa

Nucleus Gracilis & Nucleus Cuneatus

relay sensory information to the thalamus and cerebrum for conscious awareness ; together they form the Medial Lemniscus

Cardiovascular Center

regulates the rate and force of the heartbeat and the diameter of blood vessels

Medullary Rhythmicity Area

adjusts the rhythm of breathing

Vasomotor Center

regulates blood pressure by dilating or constricting blood vessels

the Olive

an oval structure that extends from the right and left lateral surfaces of the medulla ; carries impulses to the cerebellum that regulate posture and equilibrium

the Pons

superior to medulla ; bridge connecting the spinal cord and medulla to the rest of the brain

parts of the Pons

Cerebellar Peduncles and Pneumotaxic & Apneustic Areas

Cerebellar Peduncles

bundles of nerve fibers connecting the pons and the cerebellum

Pneumotaxic & Apneustic Areas

regulate breathing

the Midbrain

extends from the pons to the diencephalon

parts of the Midbrain

cerebral aqueduct, cerebral peduncles, corpora quadrigemina, substantia nigra, red nucleus, & medial lemniscus

cerebral aqueduct

passes through midbrain and connects the 3rd & 4th ventricles

cerebral peduncles

carries impulses from the pons and medulla to the thalamus

corpora quadrigemina

4 elevations located at the posterior portion of the midbrain ; found in an area called the Tectum ; 2 superior colliculi and 2 inferior colliculi

superior colliculi

serve as reflex centers for eye and head movements

inferior colliculi

serve as reflex centers for auditory stimuli

substantia nigra

darkly pigmented areas that control subconscious muscle activity ; suppresses unwanted muscle movement during contraction

red nucleus

neurons in the midbrain the coordinate muscular movements in the body ; large blood supply

medial lemniscus

band of white matter extending through the medulla, pons, and midbrain ; carries impulses for touch and pressure from the medulla to the thalamus

the Reticular Formation

an area of the brain stem that consists of gray matter interspersed with white matter

functions of the reticular formation

pain modulation, regulating sleep/wake, and screening out inconsequential stimuli

the Cerebellum

posterior to medulla and pons ; two hemispheres

transverse fissure

separates the cerebellum from the cerebrum

the Vermis

central portion of cerebellum

Cerebellar cortex

superficial layer

purkinje cells

myelinated neurons that form a visible white layer in cerebellum ; the white layer is called the arbor vitae

the Diencephalon

begins at the midbrain and extends upwards forming the walls of the 3rd ventricle ; consists of thalamus and hypothalamus

the Pineal Gland

located in diencephalon ; secretes melatonin

Thalamus

80% of diencephalon

Intermediate Mass

bridge of gray matter connecting the right and left sides of the thalamus

functions of the thalamus

relay center for impulses from the spina cord to the cerebrum and cognition

the Hypothalamus

inferior to thalamus

major parts of hypothalamus

Mammillary Bodies & the Pituitary Gland (hypophysis)

Mammillary Bodies

serve as relay stations for reflexes relating to the sense of smell

Pituitary Gland (hypophysis)

attaches to the hypothalamus via a stalk known as the infundibulum

functions of the hypothalamus

maintaining homeostasis, controlling hunger and thirst, regulating endocrine system

Satiety Center

only in humans ; tells us we are full & done eating

the Cerebrum

largest portion of the brain supported by the brain stem and diencephalon

Cerebral Cortex

superficial layer composed of gray matter ; white matter found deeper

functions of the cerebrum

site of intelligence ; allows us to speak, read, write

Gyrus

folds in cerebrum

Fissures

deep grooves between gyrus ; shallow grooves are known as sulci

Longitudinal Fissure

separates two hemispheres of cerebrum

Corpus Callosum

band of white matter that connects the two hemispheres

Lobes of the cerebrum

Frontal, Parietal, Occipital, Temporal, Insula

frontal lobe

involved in cognition and other higher processes, speech, and motor controls

parietal lobe

receive and interprets signals from the special senses ; touch/pressure

occipital lobe

visual center

temporal lobe

involved in creating hearing sensations, emotions, learning, and memory

insula

deep lobe of the cerebrum ; visceral sensation an understanding spoken language

Sensory Areas in cerebrum

general sensory, primary visual, primary auditory, primary gustatory, primary olfactory

General Sensory Area

receives nerve impulses for touch, temperature, pain, and body position

Primary Visual Area

receives impulses conveying visual information

Primary Auditory Area

receives sound impulses

Primary Gustatory Area

receives taste impulses

Primary Olfactory area

receives smell impulses

Motor Areas of the Cerebellum

Primary motor, Wernicke, and the Broca Area

Primary Motor Area

produces impulses that regulate skeletal muscle contractions

the Wernicke area

allow for recognition of spoken word

the Broca Area (motor speech area)

generates impulses that regulate the larynx, tongue, cheeks, and lips during speech

the Limbic System

consists of olfactory bulbs and mammillary bodies

types of memory

procedural and declarative

procedural memory

involves retention of motor skills

declarative memory

involves retention of events and facts

Cranial Nerves

12 pairs ; pass through various foramina of the skull as they leave the brain

Cerebrovascular Accident

caused by an interruption of blood supply to the brain ; stroke

Transient Ischemic Attack (TIA)

temporary episodes of reversible mental dysfunction

Alzheimers Disease

progressive degeneration of the brain that results in mental deterioration

Brain Tumor

any growth within the brain

Dyslexia

impairment of the brain’s ability to translate images received by the eyes into understandable language

Parkinsons Disease

disorder of CNS that results in involuntary skeletal muscle contractions of muscles that are normally under voluntary control

Huntingtons Disease

hereditary and fatal

Concussion

occurs when the brain moves within the skull

Cerebral Edema

swelling of the brain (fluid on the brain)