Brain structures and functions ppt 1

Q: What makes the human brain outstanding among mammalian brains?

A: It is the most cognitively able, larger than expected from body size, and has an overdeveloped cerebral cortex.

Q: What percentage of brain mass does the cerebral cortex represent?

A: Over 80% of brain mass.

Q: How many neurons does the cerebral cortex contain?

A: About 100 billion neurons.

Q: How many more glial cells are there compared to neurons in the cerebral cortex?

A: 10 times more glial cells.

Q: What is the function of the association cortex (prefrontal area)?

A: It is responsible for memory, emotions, reasoning, will, judgment, personality traits, aggression, intelligence, artistic and creative ability, and learning.

Q: What does the primary motor cortex do?

A: It stages each planned movement initiated in the premotor area.

Q: What is the function of the parietal lobe?

A: It contains the primary somatic sensory cortex, which receives general sensory inputs such as touch, pain, temperature, balance, and taste.

Q: What is the function of the occipital lobe?

A: It contains the visual cortex responsible for reception and integration of visual input.

Q: What is the function of the temporal lobe?

A: It contains the auditory cortex, evaluates olfactory and auditory input, plays a role in memory, and is involved in abstract thought and judgment.

Q: What is the main role of the cerebellum?

A: To monitor and regulate motor behavior without the need for conscious awareness.

Q: What are the functions of the cerebellum?

A: It controls subconscious movement in skeletal muscles, coordination, posture, balance, spatial orientation, motor and sequence learning, and normal muscle tone.

Q: What does the epithalamus regulate?

A: Biological rhythms such as sleep/wake cycles.

Q: How is melatonin secretion regulated?

A: It is light dependent.

Q: What gland is associated with the epithalamus?

A: The pineal gland.

Q: What does the pineal gland secrete?

A: Melatonin.

Q: How does the epithalamus affect behavior?

A: Through regulation of biological rhythms and melatonin secretion.

Q: What is the function of the pineal gland in puberty regulation?

A: It regulates the onset of puberty by inhibiting gonadotropic hormones (GRH) in the pituitary gland.

Q: What effect does high melatonin from the pineal gland have on the pituitary gland?

A: It stops the pituitary gland’s secretion of GRH.

Q: What happens when the pituitary gland releases GRH?

A: It stimulates secretion of sex hormones such as estrogen, progesterone, and testosterone.

Q: How does melatonin secretion vary with age?

A: Young children secrete high amounts of melatonin, and the pineal gland disintegrates with age.

Q: What is the main function of the thalamus?

A: It acts as a relay center that sorts incoming stimuli and routes sensory impulses (except smell) to the appropriate portion of the cerebrum for interpretation.

Q: What sensory information does the thalamus interpret?

A: Sensory impulses for pain, temperature, pressure, and touch.

Q: What nickname is given to the thalamus?

A: The “Switchboard.”

Q: What are the functions of the hypothalamus?

A: It regulates autonomic (visceral) functions, sleep patterns, appetite and thirst via the mamillary body, body temperature, and the endocrine system via the pituitary gland.

Q: What emotions or behaviors are associated with the hypothalamus?

A: Feelings of rage, aggression, and sexual behavior.

Q: What is another name for the midbrain?

A: The mesencephalon.

Q: What is the dorsal portion of the midbrain called?

A: The corpora quadrigemina.

Q: What are the superior colliculi?

A: Reflex centers for movements of the eyeball and visual stimulation.

Q: What do the superior colliculi control?

A: Pupil diameter and lens shape.

Q: What are the inferior colliculi?

A: Reflex centers for head and trunk movements in response to auditory stimulation.

Q: What is the ventral portion of the midbrain called?

A: The cerebral peduncles.

Q: What do the cerebral peduncles contain?

A: Sensory and motor tracts.

Q: What functions does the pons control?

A: Respiration, swallowing, chewing, salivation, and balance.

Q: What additional function does the pons serve?

A: It acts as a relay center to the cerebrum and between cerebellar hemispheres.

Q: What are the main functions of the medulla oblongata?

A: It serves as a relay center, controls consciousness and arousal, and functions as a visceral autonomic center.

Q: What is the medullary rhythmicity area responsible for?

A: Regulation of respiration.

Q: What does the cardiac center in the medulla oblongata control?

A: Heart rate and force of contraction.

Q: What does the vasomotor center regulate?

A: Blood vessel diameter through constriction and dilation.

Q: What autonomic reflexes are controlled by the medulla oblongata?

A: Vomiting, coughing, sneezing, hiccupping, and swallowing.

Q: What is the result of damage to the medulla oblongata?

A: It almost always results in death.

Q: What can mild brain activity disturbances cause?

A: Subtle changes in consciousness, motor control, or sensory perception.

Q: What can severe brain activity disturbances cause?

A: Jerky, involuntary muscle contractions leading to convulsions or unconsciousness.

Q: What protects the brain physically and chemically?

A: The meninges, cerebrospinal fluid (CSF), and the blood-brain barrier (BBB).

Q: What are the three protective coverings of the brain?

A: The dura mater, arachnoid mater, and pia mater.

Q: What is meningitis?

A: Inflammation of the meninges.

Q: What are the symptoms of meningitis?

A: Fever, headache, stiff neck, vomiting, confusion, and sometimes seizures.

Q: What causes meningitis?

A: Bacteria, viruses, fungi, or other microorganisms.

Q: How is bacterial meningitis transmitted?

A: Through respiratory droplets or direct contact with infected secretions.

Q: How is viral meningitis usually transmitted?

A: By fecal-oral route or contact with respiratory secretions.

Q: What diagnostic test is used for meningitis?

A: Lumbar puncture (spinal tap) to collect cerebrospinal fluid.

Q: What is cerebrospinal fluid (CSF)?

A: A clear fluid that surrounds and cushions the brain and spinal cord.

Q: What are the functions of CSF?

A: It provides mechanical protection, chemical stability, and nutrient transport for the brain and spinal cord.

Q: What structures produce CSF?

A: The choroid plexuses located in the brain ventricles.

Q: What are the three contributors to CSF production?

A: The choroid plexuses, the ependymal lining of ventricles, and the subarachnoid space.

Q: How does CSF circulate through the brain?

A: It flows through the ventricles, central canal of the spinal cord, and subarachnoid space around the brain and spinal cord.

Q: How is CSF reabsorbed into the bloodstream?

A: Through arachnoid villi (granulations) into the dural venous sinuses.

Q: What happens if CSF reabsorption is blocked?

A: It can lead to hydrocephalus, an accumulation of CSF causing pressure on the brain.

Q: What is the function of the blood-brain barrier (BBB)?

A: It protects the brain by preventing harmful substances from entering from the bloodstream while allowing essential nutrients to pass through.

Q: What structure provides the brain’s blood supply redundancy?

A: The Circle of Willis (Cerebral Arterial Circle).

Q: What is the function of the Circle of Willis?

A: It ensures continuous blood flow to the brain even if one artery is blocked or narrowed.

Q: Which major arteries form the Circle of Willis?

A: The internal carotid arteries and the basilar artery.

Q: What does the Circle of Willis supply blood to?

A: The cerebrum and other parts of the brain.

Q: What is the function of cerebral arteries?

A: supply blood to the cerebrum and other parts of the brain.

Q: What happens if blood flow to the brain is interrupted for several seconds?

A: It can cause loss of consciousness.

Q: What happens if blood flow to the brain is interrupted for several minutes?

A: It can result in brain damage or death of neural tissue.

Q: What is the blood-brain barrier (BBB)?

A: A selective permeability barrier that isolates the brain from the general circulation.

Q: What forms the blood-brain barrier?

A: Tight junctions between endothelial cells, basement membrane, and astrocyte processes.

Q: What substances can cross the blood-brain barrier easily?

A: Glucose, oxygen, certain ion (Na+ and K+)

Q: What substances cannot cross the blood-brain barrier easily?

A: Proteins, toxins, and most medications.

Q: Why is the blood-brain barrier important?

A: It maintains a stable environment for the brain by regulating the movement of ions, nutrients, and waste products.

Q: What can damage the blood-brain barrier?

A: Trauma, inflammation, infection, or hypertension.

Q: How can the blood-brain barrier affect drug treatment?

A: It limits the entry of many therapeutic drugs into the brain, complicating treatment of neurological diseases.

Q: What is one clinical consequence of blood-brain barrier disruption?

A: It can allow harmful substances or pathogens to enter brain tissue, leading to swelling or infection.