860 likes | 3.18k Views
Neuroanatomy. The Human Brain. I. Directional Terms. Dorsal - “toward the back.” Ventral - “towards the stomach or bottom.” Anterior – “towards the front.” Posterior - “towards the rear or back.”. Terms contd. Rostral – “towards front nostrils.” Caudal - “towards the tail.”
E N D
Neuroanatomy The Human Brain
I. Directional Terms • Dorsal- “toward the back.” • Ventral- “towards the stomach or bottom.” • Anterior – “towards the front.” • Posterior- “towards the rear or back.”
Terms contd. • Rostral – “towards front nostrils.” • Caudal- “towards the tail.” • Superior- “top of head” • Inferior- “bottom of head” • Lateral – “to the side” • Medial – “to the middle” • Ipsilateral – “same side” • Contralateral – “opposite side”
II. Brain Slices: • 1. Coronal – slices brain from front to back. Resembles a butterfly in most slices.
Brain slices (contd) • 2. Sagittal (midsagittal) – slices the brain down the midline so you can see what’s on each half.
Brain slices • 3. Horizontal – slices the brain from top to bottom.
IV. Cortical Landmarks • 1. Gyrus (gyri) – bulges on the brain’s surface. • 2. Sulcus (sulci) – a small ridge in the cortex. • 3. Fissure (s) – a large ridge in the cortex.
B. Sulci- Central sulcus- separates frontal lobe from parietal lobe.
C. Fissures- • 1. Sylvian (Lateral Fissure)- Large ridge that separates temporal lobe from other lobes.
Fissures (contd.) • 2. Longitudinal fissure – separates left & right hemispheres. • Left Right
V. CNS & PNS terms • Nuclei – cell bodies in the CNS. • Ganglion – cell bodies in the PNS • Tracts – Axon bundles in the CNS • Nerves – Axon bundles in the PNS
Terms contd. • White matter –composed of axon bundles. Is white because of the myelin sheaths (white fatty tissue) that cover the axons. • Gray matter – composed of clusters of cell bodies, have dark gray appearance from cell body structures.
VI. Three Divisions of the Brain • 1. Hindbrain – oldest part of brain, governs basic functions (breathing, regulates heart beat). • 2. Midbrain – involved in some perceptual & motor functions. • 3. Forebrain – governs all higher-order level functions (problem solving, planning, emotion regulation, language).
VII. The Hindbrain- • consists of the medulla, pons, & cerebellum.
A. Medulla (oblongata): • a structure just above spinal cord. Controls & regulates vital reflexes for survival (respiration, HR, vomiting, salivation, coughing, & sneezing). • Damage to the Medulla is almost always fatal.
B. Pons: • An enlarged protrusion anterior to the medulla. Both pons & medulla form reticular formation & raphe system. • Plays a role in arousal & dreaming.
C. Cerebellum: (means little brain) • Large hindbrain structure that is posterior to the brainstem. • Governs motor functions, motor memory.
VIII. The Midbrain Most obvious feature is the tectum (“roof”). Two pairs of bumps on tectum: Superior colliculi (vision) Inferior colliculi (audition) Substantia nigra—part of basal ganglia, involved in movement (Parkinson’s disease).
IX. The Forebrain • Consists of subcortical and cortical structures. • 1. Subcortical structures include the thalamus, hypothalamus, limbic system, & basal ganglia.
A. Thalamus- • A large two-lobed structure that sits on top of the brainstem. Is brain’s sensory relay station. • Several nuclei receive sensory input & send that input to parts of the cortex. • Nuclei: Lateral geniculate nuceli (visual), medial geniculate nuceli (auditory) & ventral posterior nuclei (somatosensory)
B. Hypothalamus • Is ventral to the thalamus. Receives projections from the fornix in its mammilary bodies. • Function: regulation • Of basic motivational • Drives (sex, hunger, • thirst, fighting).
C. Limbic system • Comprised of the fornix, hippocampus, amygdala, septum, & cingulate gyrus.
Limbic system • Fornix (“arch”) is the major pathway of the limbic system; projects in an arc from the hippocampus into mammilary bodies of the hypothalamus. • Hippocampus “seahorse” is the structure that lies in between the cortex & thalamus, rests in the temporal lobe; plays a large role in LTM storage.
Limbic system • Amygdala – “almond” lies anterior to the hippocampus, is involved in basic emotions (fear, anger).
2. Cortical structures- • Lobes of the brain
Occipital lobe • Most posterior portion of brain. Processes visual sensory information. • Houses primary visual cortex (striate cortex). • Damage to PVC can cause • “cortical blindness.”
B. Parietal lobe • Is posterior to the frontal lobe & dorsal to temporal lobe. Processes visual & tactile sensory information. • Houses primary • Somatosensory cortex • Which receives sensory • Info from skin.
C. Temporal lobe • Processes auditory and visual information. Houses primary auditory cortex—the primary projection site for auditory stimuli. • Language, face recognition, • & processing of sounds • Occurs here.
D. Frontal lobe: • Processes information for planning, executive control, fine movement, emotion regulation, higher-order cognitive functions.