Contains approximately 100 billion neurons.
Weighs about 1.6 kg in males and 1.45 kg in females.
Weight proportional to body size.
Composed of two hemispheres and multiple lobes.
Size of the brain does not correlate with intelligence; complexity is key to processing power.
Question: How does the brain produce the mind?
Current Understanding: The workings of the brain remain largely unknown.
Insights into brain function primarily derived from studies of accident or stroke victims.
Imaging Techniques:
PET (Positron Emission Tomography): Visualizes brain activity.
MRI (Magnetic Resonance Imaging): Shows brain structure and function.
Cerebrum
Diencephalon
Thalamus
Hypothalamus
Epithalamus
Brain Stem
Midbrain (Mesencephalon)
Pons
Medulla Oblongata
Cerebellum
Largest brain part; responsible for higher mental functions.
Divided into left and right cerebral hemispheres.
Consists of neural cortex (gray matter) which facilitates conscious thought and intelligence.
Second largest part of the brain.
Coordinates repetitive body movements.
Features two hemispheres and is covered by cerebellar cortex.
Purkinje neurons play a major role in controlling motor activities initiated by the frontal motor cortex.
Located beneath the cerebrum and cerebellum.
Thalamus: Relays sensory information; involved in learning and memory.
Hypothalamus: Associated with hormone production, emotion, and autonomic functions.
Pituitary gland: Major endocrine gland connected to the hypothalamus.
Processes information between the spinal cord and the cerebrum or cerebellum.
Midbrain: Manages sight, sound, and related reflexes.
Pons: Involved in motor control.
Medulla Oblongata: Regulates autonomic functions (heart rate, blood pressure, digestion).
The Cranial Meninges:
Comprising three layers:
Dura mater
Arachnoid mater
Pia mater
Continuous with spinal meninges; provides protection against cranial trauma.
Each hemisphere divided into: frontal, parietal, temporal, and occipital lobes.
Contains centers for reasoning, movement, somatic sensing, hearing, and vision.
Central Sulcus: Divides frontal and parietal lobes.
Precentral Gyrus: Primary motor cortex.
Postcentral Gyrus: Primary somatosensory cortex.
Other landmarks include parieto-occipital sulcus, lateral sulcus, and transverse cerebral fissure.
Accounts for about 40% of the brain’s mass; thickness of 2-4 mm.
Center of conscious thought containing neuron cell bodies and dendrites.
Folds in the cortex increase surface area for processing.
Three functional activity types:
Motor
Sensory
Association
Each hemisphere controls the opposite side of the body.
No individual brain area works alone; consciousness involves multiple areas.
Premotor Cortex: Involved in learned, repetitive movements (e.g., playing piano).
Language Areas:
Broca's Area: Speech production, only located in the left hemisphere.
Primary Somatosensory Area: Localizes sensation points.
Auditory Area: Processes pitch, rhythm, and loudness.
Responsible for functions like self-awareness, initiative, and planning ahead.
Procedure that disconnects frontal lobes leading to loss of strong emotional reactions.
Previously used in psychiatry but now considered obsolete due to negative effects on behavior and planning.
Involved in intellect, complex learning, personality, judgment, and planning.
Wernicke’s Area: Involved in understanding language.
Broca’s Area: Speech production.
Each hemisphere is dominant for specific activities:
Left Hemisphere: Language, math, logic (dominance in 90% of people).
Right Hemisphere: Creative skills, intuition, emotion, appreciation of art and music.
Most left-dominant individuals are right-handed.
Occurs in about 10% of the population, often more common in left-handed males.
Controls the Autonomic Nervous System and homeostasis:
Emotion responses, body temperature, food intake, water balance, sleep-wake cycles.
Supports endocrine functions through the Pituitary gland.
Controls reflex activities independently from the brain.
Conducts signals to and from the brain.
Located within the vertebral column and acts as a major reflex center.
The Spinal Meninges protect the spinal cord and contain blood supply. Continues from cranial meninges.
Meningitis: Infection resulting from viruses or bacteria, causing inflammation of the meninges.
Peripheral regions contain white matter (sensory and motor neurons).
Central region contains gray matter (nerve cell bodies around the central canal).
Gray matter divided into horns; identifiable features include anterior median fissure, posterior medial sulcus, and gray commissure.
Tapers and ends at conus medullaris (between L1 and L2).
Filum terminale attaches the spinal cord to the coccyx.
Cauda equina refers to the final pairs of spinal nerves at the end.
Each spinal cord segment connected by a pair of spinal nerves.
Spinal nerves are surrounded by three connective tissue layers that include blood vessels.
Regions of the skin innervated by cutaneous branches of spinal nerves.
Meningitis: Inflammation of the meninges (can be viral or bacterial).
Encephalitis: Brain inflammation due to viral infections, often associated with bites from ticks or mosquitoes.
Concussion: Caused by blow to the head without visible damage; leads to cognitive problems.
Contusion: Results from bleeding and visible bruising, with effects dependent on the injury location.
Initial chickenpox infection by varicella zoster virus can later lead to herpes zoster (shingles).
Prions: Misfolded proteins that cause diseases like mad cow disease and Creutzfeldt-Jacob disease.
Discovered by Stanley Prusiner; he earned a Nobel Prize in 1997.
Infectious agents characterized by two forms of PrP:
Normal PrP: Functional and composed primarily of a-helices.
Prion PrP: Causes disease and involves beta-sheets, converting normal proteins into the misfolded form.
The Brain and spinal cord
Contains approximately 100 billion neurons.
Weighs about 1.6 kg in males and 1.45 kg in females.
Weight proportional to body size.
Composed of two hemispheres and multiple lobes.
Size of the brain does not correlate with intelligence; complexity is key to processing power.
Question: How does the brain produce the mind?
Current Understanding: The workings of the brain remain largely unknown.
Insights into brain function primarily derived from studies of accident or stroke victims.
Imaging Techniques:
PET (Positron Emission Tomography): Visualizes brain activity.
MRI (Magnetic Resonance Imaging): Shows brain structure and function.
Cerebrum
Diencephalon
Thalamus
Hypothalamus
Epithalamus
Brain Stem
Midbrain (Mesencephalon)
Pons
Medulla Oblongata
Cerebellum
Largest brain part; responsible for higher mental functions.
Divided into left and right cerebral hemispheres.
Consists of neural cortex (gray matter) which facilitates conscious thought and intelligence.
Second largest part of the brain.
Coordinates repetitive body movements.
Features two hemispheres and is covered by cerebellar cortex.
Purkinje neurons play a major role in controlling motor activities initiated by the frontal motor cortex.
Located beneath the cerebrum and cerebellum.
Thalamus: Relays sensory information; involved in learning and memory.
Hypothalamus: Associated with hormone production, emotion, and autonomic functions.
Pituitary gland: Major endocrine gland connected to the hypothalamus.
Processes information between the spinal cord and the cerebrum or cerebellum.
Midbrain: Manages sight, sound, and related reflexes.
Pons: Involved in motor control.
Medulla Oblongata: Regulates autonomic functions (heart rate, blood pressure, digestion).
The Cranial Meninges:
Comprising three layers:
Dura mater
Arachnoid mater
Pia mater
Continuous with spinal meninges; provides protection against cranial trauma.
Each hemisphere divided into: frontal, parietal, temporal, and occipital lobes.
Contains centers for reasoning, movement, somatic sensing, hearing, and vision.
Central Sulcus: Divides frontal and parietal lobes.
Precentral Gyrus: Primary motor cortex.
Postcentral Gyrus: Primary somatosensory cortex.
Other landmarks include parieto-occipital sulcus, lateral sulcus, and transverse cerebral fissure.
Accounts for about 40% of the brain’s mass; thickness of 2-4 mm.
Center of conscious thought containing neuron cell bodies and dendrites.
Folds in the cortex increase surface area for processing.
Three functional activity types:
Motor
Sensory
Association
Each hemisphere controls the opposite side of the body.
No individual brain area works alone; consciousness involves multiple areas.
Premotor Cortex: Involved in learned, repetitive movements (e.g., playing piano).
Language Areas:
Broca's Area: Speech production, only located in the left hemisphere.
Primary Somatosensory Area: Localizes sensation points.
Auditory Area: Processes pitch, rhythm, and loudness.
Responsible for functions like self-awareness, initiative, and planning ahead.
Procedure that disconnects frontal lobes leading to loss of strong emotional reactions.
Previously used in psychiatry but now considered obsolete due to negative effects on behavior and planning.
Involved in intellect, complex learning, personality, judgment, and planning.
Wernicke’s Area: Involved in understanding language.
Broca’s Area: Speech production.
Each hemisphere is dominant for specific activities:
Left Hemisphere: Language, math, logic (dominance in 90% of people).
Right Hemisphere: Creative skills, intuition, emotion, appreciation of art and music.
Most left-dominant individuals are right-handed.
Occurs in about 10% of the population, often more common in left-handed males.
Controls the Autonomic Nervous System and homeostasis:
Emotion responses, body temperature, food intake, water balance, sleep-wake cycles.
Supports endocrine functions through the Pituitary gland.
Controls reflex activities independently from the brain.
Conducts signals to and from the brain.
Located within the vertebral column and acts as a major reflex center.
The Spinal Meninges protect the spinal cord and contain blood supply. Continues from cranial meninges.
Meningitis: Infection resulting from viruses or bacteria, causing inflammation of the meninges.
Peripheral regions contain white matter (sensory and motor neurons).
Central region contains gray matter (nerve cell bodies around the central canal).
Gray matter divided into horns; identifiable features include anterior median fissure, posterior medial sulcus, and gray commissure.
Tapers and ends at conus medullaris (between L1 and L2).
Filum terminale attaches the spinal cord to the coccyx.
Cauda equina refers to the final pairs of spinal nerves at the end.
Each spinal cord segment connected by a pair of spinal nerves.
Spinal nerves are surrounded by three connective tissue layers that include blood vessels.
Regions of the skin innervated by cutaneous branches of spinal nerves.
Meningitis: Inflammation of the meninges (can be viral or bacterial).
Encephalitis: Brain inflammation due to viral infections, often associated with bites from ticks or mosquitoes.
Concussion: Caused by blow to the head without visible damage; leads to cognitive problems.
Contusion: Results from bleeding and visible bruising, with effects dependent on the injury location.
Initial chickenpox infection by varicella zoster virus can later lead to herpes zoster (shingles).
Prions: Misfolded proteins that cause diseases like mad cow disease and Creutzfeldt-Jacob disease.
Discovered by Stanley Prusiner; he earned a Nobel Prize in 1997.
Infectious agents characterized by two forms of PrP:
Normal PrP: Functional and composed primarily of a-helices.
Prion PrP: Causes disease and involves beta-sheets, converting normal proteins into the misfolded form.