Week 5 // Brain Flashcards
When and where does the development of the nervous system begin?
The development of the nervous system begins with a thickening of the ectoderm called the neural tube
3-4 week old embryo (brain begins)
Brain stem includes the
mid brain, pons, medulla oblongata
midbrain: reflective movement of eyebrow, auditory/visual stimulus),
pons: helps medulla control breathing
medulla oblongata: swallowing, blood rate, sweating, pressure… continues to spinal cord
Diencephalon includes the
Thalamus, hypothalamus, pineal gland
Cerebellum
Posterior part of head (below occipital lobe area)
Ventricles
The ventricles of the brain are a communicating network of cavities in center of brain, filled with cerebrospinal fluid (CSF)
the brain is protected by
cranial bones, cerebrospinal fluid and cranial meninges
Cranial meninges
3 layers:
Pia (deep layer), arachnoid (mid layer), and dura mater (outermost 2 layers)
Blood flows to the brain via the ______& _______ and flows back to the heard via the __________
Blood flows to the brain via the vertebral and carotid arteries and flows back to the heart via the jugular veins
The brain uses about _____% of body’s oxygen supply
20%
Any interruption of the oxygen supply can result in
weakening, permanent damage, or death of brain cells
Glucose deficiency may produce mental confusion, dizziness, convulsions, and unconsciousness
What is the Blood-Brain Barrier (BBB)?
The BBB protects brain cells from harmful substances and pathogens by serving as a selective barrier to prevent passage of many substances from the blood into the brain
The BBB can prevent the entry of therapeutic drugs
Injury to the brain may cause a breakdown of the BBB, permitting the passage of normally restricted substances into the brain tissue
Cerebrospinal Fluid (CSF)
C S F is a liquid that protects the brain and spinal cord against chemical and physical injuries and it carries oxygen, glucose, and other important substances from the blood to nervous tissue cells
Ventricles of the brain
The ventricles of the brain contain C S F
Choroid Plexus
The choroid plexuses make C S F
Where is the medulla oblongata
The medulla oblongata is continuous with the superior aspect of the spinal cord and contains portions of both motor and sensory tracts
Medulla Oblongata contains these Cranial nerves
Vestibulocochlear (CN 8) and hypoglossal (CN 12)
The vestibulocochlear nerve consists of the vestibular and cochlear nerves. The vestibular nervehandles balance and equilibrium, while the cochlear nerve is responsible for hearing. The hypoglossal nerveenables tongue movement. (After stroke, hypoglossal nerves can be damaged)
Functional regions of medulla oblongata
Heart rate, respiratory rate, vasoconstriction, swallowing, coughing, vomiting, sneezing, hiccupping
Pons location
The pons is located superior to the medulla oblongata and it links parts of the brain with one another by way of tracts
The pons is part of a highway-like structure between the brain and the body known as the brainstem. The brainstem is made up of three sections, and carries vital information to the body. The pons relays information about motor function, sensation, eye movement, hearing, taste, and more.
Pons Cranial Nerves
Cranial nerves
Trigeminal, abducens, facial, and vestibular branch of vestibulocochlear
Pons functional regions
Functional regions
Relays nerve impulses related to voluntary skeletal muscle movements from cerebrum to cerebellum
Pneumotaxic and apneustic areas (control of respiration)
Midbrain location
The midbrain is located superior to the medulla oblongata and extends from the pons to the diencephalon
Midbrain Cranial Nerves
Cranial nerves = Oculomotor and trochlear
Structural regions
Cerebral peduncles, corpora quadrigemina, substantia nigra, red nuclei, and medial lemniscus
Midbrain Functional regions
Functional regions
Conveys motor impulses from the cerebrum to the cerebellum and spinal cord, sends sensory impulses from the spinal cord to the thalamus, and regulates auditory and visual reflexes
Reticular Formation
The reticular formation helps regulate muscle tone, alerts the cortex to incoming sensory signals, and is responsible for maintaining consciousness and awakening from sleep
Brainstem functions : Medulla oblongata not on exam
Medulla oblongata: Contains sensory (ascending) and motor (descending) tracts. Cardiovascular center regulates heartbeat and blood vessel diameter. Medullary respiratory center (together with pons) regulates breathing. Contains gracile nucleus, cuneate nucleus, gustatory nucleus, cochlear nuclei, and vestibular nuclei (components of sensory pathways to brain). Inferior olivary nucleus provides instructions that cerebellum uses to adjust muscle activity when learning new motor skills. Other nuclei coordinate vomiting, swallowing, sneezing, coughing, and hiccupping. Contains nuclei of origin for vestibulocochlear (VIII), glossopharyngeal (IX), vagus (X), accessory (XI), and hypoglossal (XII) nerves. Reticular formation (also in pons, midbrain, and diencephalon) functions in consciousness and arousal.
Brainstem functions : Pons not on exam
Pons: Contains sensory and motor tracts. Pontine nuclei relay nerve impulses from motor areas of cerebral cortex to cerebellum. Contains vestibular nuclei (along with medulla) that are part of equilibrium pathway to brain. Pontine respiratory group (together with the medulla) helps control breathing. Contains nuclei of origin for trigeminal (V), abducens (VI), facial (VII), and vestibulocochlear (VIII) nerves.
Brainstem functions : Midbrain not on exam
Midbrain: Contains sensory and motor tracts. Superior colliculi coordinate movements of head, eyes, and trunk in response to visual stimuli. Inferior colliculi coordinate movements of head, eyes, and trunk in response to auditory stimuli. Substantia nigra and red nucleus contribute to control of movement. Contains nuclei of origin for oculomotor (III) and trochlear (IV) nerves.
The Cerebellum
The cerebellum occupies the inferior and posterior aspects of the cranial cavity and consists of two hemispheres and a central vermis
The Cerebellum functions
The cerebellum functions in the coordination of skeletal muscle contractions and in the maintenance of normal muscle tone, posture, and balance.
Normal posture, normal balance.
The Diencephalon
The diencephalon is composed of the:
Thalamus, Hypothalamus and Epithalamus
Thalamus
Thalamus (located superior to the midbrain and contains nuclei that serve as relay stations for all sensory impulses -except smell- to the cerebral cortex. Track for signals from spinal cord. Important in sleep, emotions, all sensory input)
Hypothalamus
The hypothalamus is found inferior to the thalamus, has four major regions, controls many body activities, and is one of the major regulators of homeostasis.
Epithalamus
The epithalamus lies superior and posterior to the thalamus and contains the pineal gland. The pineal gland secretes melatonin and the habenular nuclei are involved in olfaction.
Circumventricular Organs (CVOs) of the Diencephalon
NO BBB! Monitor changes in blood.
Parts of the diencephalon, the CVOs, can monitor chemical changes in the blood because they lack a blood-brain barrier.
CVOs include a portion of the hypothalamus, the pineal gland, and the pituitary gland
CVOs coordinate homeostatic activities of the endocrine and nervous systems
Overall functions of Diencephalon (thalamus, hypothalamus, epithalamus).
Thalamus: Relays almost all sensory input to cerebral cortex. Contributes to motor functions by transmitting information from cerebellum and corpus striatum to primary motor cortex of cerebral cortex. Plays role in maintenance of consciousness.
Hypothalamus: Controls and integrates activities of autonomic nervous system. Produces hormones, including releasing hormones, inhibiting hormones, oxytocin, and antidiuretic hormone. Regulates emotional and behavioral patterns (together with limbic system). Contains feeding and satiety centers (regulate eating), thirst center (regulates drinking), and suprachiasmatic nucleus (regulates circadian rhythms). Controls body temperature by serving as body’s thermostat.
Epithalamus: Consists of pineal gland (secretes melatonin) and habenular nuclei (involved in olfaction).
The Cerebrum
The cerebral cortex is composed of gray matter which contains billions of neurons
Gyri, fissures, and sulci can be identified on the cortex
Deep to the cortex is white matter composed of tracts of neurons that connect parts of the brain to each other and the spinal cord
The cerebrum can be divided into these lobes
- Frontal lobe
- Parietal lobe
- Temporal lobe
- Occipital lobe
- Insula
A bundle of white matter tracts in the cerebrum connects the right and left hemispheres of the cerebrum
the corpus callosum
The cerebral cortex is composed of _____ matter
gray
Deep to the cortex is white matter composed of tracts of neurons that connect
parts of the brain to each other and the spinal cord
Basal Nuclei of the Cerebrum
The basal nuclei are paired masses of gray matter in each cerebral hemisphere
The Limbic System
The limbic system is found in the cerebral hemispheres and diencephalon
(Not on ppt: The limbic system is the part of the brain involved in our behavioural and emotional responses, especially when it comes to behaviours we need for survival: feeding, reproduction and caring for our young, and fight or flight responses.)
Organization of the Cerebral Cortex :
3 Functional Regions
Specific types of sensory, motor, and integrative signals are processed in certain regions of the cerebral cortex.
Sensory areas
Motor areas
Association areas
ADD PHOTO OF CEREBRAL CORTEX AND FUNCTIONS
visual cortex / primary motor cortex / pre-motor cortex / visual association area / etc
Summary or Cerebrum functions
cerebral cortex, corpus stratum, limbic system
Sensory areas of cerebral cortex are involved in perception of sensory information; motor areas control execution of voluntary movements; association areas deal with more complex integrative functions such as memory, personality traits, and intelligence.
Corpus striatum helps initiate and terminate movements, suppresses unwanted movements, and regulates muscle tone.
Limbic system promotes range of emotions, including pleasure, pain, docility, affection, fear, and anger.
Hemispheric Lateralization
Functional Differences between Right and Left Hemispheres
Right hemisphere of the brain
- right hemisphere receives right somatic signals from left side of body and vice versa
- Music and artistic awareness
- Space and pattern
- Recognition of face
- generate mental image to compare
- generating and discriminating between odors
- damage often have monotonous voice
Left hemisphere of the brain
- Numeric Scientific Skills
- Reasoning
- spoken and written language
- emotional content of language
- ability to use sign language
- damage often exhibit : aphasia
