University:
Glendale Community College
Course:
BIO160 | Introduction to Human Anatomy and Physiology
Academic year:

2022
Views:

136

Pages:

14
Author:

BoasiaHoprh

Brain Regions Thalamus Pituitary Gland Pons Medulla Oblongata Pineal Gland Colliculi View of Diencephalon and Brainstem with Cerebrum and Cerebellum Removed Cerebral Peduncle Diencephalon = thalamus and hypothalamus and pineal Brainstem = midbrain, medulla and pons Hindbrain: Pons, Medulla and Cerebellum • Pons, medulla and cerebellum make up the “hindbrain” • The hindbrain is located between the spinal cord and cerebral hemispheres • Nuclei (clusters of neurons) in these regions control many involuntary, life sustaining processes including respiration, circulation and digestion. Pons • Connects cerebrum and cerebellum through the tracts of axons called the cerebellar peduncles • Nuclei (clusters of neurons) coordinate auditory and vestibular (balance) sensory information with some motor responses. • Several cranial nerves branch off the pons (V, VI, VII, and VIII) Medulla • Formally called the Medulla Oblongata • Connects the spinal cord to pons • Contains nuclei that control: – Cardiac Center adjusts rate and force of heart beat – Vasomotor Center adjusts blood vessel diameter – Respiratory Centers control rate and depth of breathing • Reflex centers for coughing, sneezing, gagging, vomiting, sweating • Last 4 cranial nerves branch off the medulla oblongata (IX, X,XI, XII) Cerebellum • Primary role in skeletal muscle coordination and motor learning • Also functions in awareness, memory and emotion. • Contains about 100 billion neurons including highly dendritic Purkinje cells that integrate information and send information out into a complex network of white matter called the arbor vitae. Midbrain • The midbrain is the upper part of the brainstem that connects the forebrain and the hindbrain. • Important parts of the midbrain include the: • superior colliculus • inferior colliculus • substantia nigra • reticular formation Corpora Quadragemina: Superior and Inferior Colliculi • The corpora quadrigemina are 4 nuclei in the midbrain: – top two nuclei form the superior colliculus which control visual reflexes like visually track moving objects – bottom two nuclei form the inferior colliculus which controls the auditory reflex of turning of the head towards sound Midbrain Nuclei • Midbrain nuclei are involved in visual reflexes, auditory relays and motor coordination. • Substantia Nigra uses the inhibitory neurotransmitter dopamine to regulate motor pathways and help control skeletal muscles. Degeneration leads to the tremors of Parkinson disease. Reticular Formation • The reticular formation is composed of about 100 nuclei in the brainstem that relay information to the cerebral cortex. • Some tracts regulate balance and posture. • Gaze centers allow you to fixate on objects. • Initiates habituation to repetitive, unimportant stimuli (background noise). • Regulates sleep and conscious attention. • Can block pain signals to the brain. • Damage leads to coma (loss of consciousness). • Thalamus • Egg-shaped masses of gray matter composed of several nuclei. • Receives nearly all sensory information on its way to the cerebral cortex then integrates and directs the information to an appropriate area of the brain. • Interconnected to limbic system so it is also involved in emotion and memory. Hypothalamus • Nuclei in walls and floor of third ventricle • Homeostatic Functions – – – – pituitary gland control autonomic NS control thermoregulation food and water intake (hunger and satiety) – sleep/activity rhythms – memory (mammillary bodies) – emotional behavior (anger aggression, fear, pleasure, contentment, sexuality) Epithalamus Pineal Gland • The Pineal Gland is the main part of the Epithalamus. • Melatonin produced by pineal gland is involved in activity cycles and in controlling onset of puberty. Cerebrum • Cerebrum is divided into 5 lobes. • The fifth lobe, the Insula, is deep to the lateral sulcus.