Lesson 2: The Lower Brain:

Parts of the Brain: The parts of the brain can also be divided into 3 areas: FOREBRAIN. MIDBRAIN. HINDBRAIN.

Forebrain: The FOREBRAIN is made up of the TELENCEPHALON and the DIENCEPHALON.

Telencephalon: TELENCEPHALON: The largest part of the brain. It is made up of the CEREBRAL CORTEX The CEREBRAL HEMISPHERES.

Cerebral Cortex: CEREBRAL CORTEX: the heavily folded outer (wrinkled) layer of the brain: Responsible mostly for conscious thought, higher level thinking, movement, and sensation.

Lobes of the Brain: The cerebral cortex is divided into four (4) lobes: FRONTAL LOBE. PARIETAL LOBE. TEMPORAL LOBE(s). OCCIPITAL LOBE.

Lower Brain: LOWER BRAIN: The part of the brain that regulates basic body functions such as breathing, heart rate, blood pressure, etc… Located inside the cerebral cortex.

Diencephalon: The DIENCEPHALON is made up of the THALAMUS and the HYPOTHALAMUS.

Thalamus: THALAMUS: The relay station; it relays information from the senses to the cerebral cortex.

Thalamus: Part of the cerebral cortex that sits on top of the brain stem. An oval mass of nerve cells. It is the part of the lower brain that functions as a relay station between the senses and the cerebral cortex. It receives and transmits incoming and outgoing messages between the brain and the rest of the body: Ex: move your little finger.

Hypothalamus: HYPOTHALAMUS: Means “below the thalamus.” Has control of the body’s automatic processes. The part of the lower brain that controls the release of hormones by regulating the pituitary gland.

Hypothalamus: Hypo means “below.” It is located below the Thalamus. It is the size of a large pea. It regulates the ANS (Autonomic Nervous System): Ex: regulation of body temperature. It influences behavior by controlling the releasing hormones. Part of the lower brain that regulates basic needs and emotions. Hunger, thirst, pleasure, fear, rage, desire, sexuality, etc…

Midbrain: Also known as the MESENCEPHALON. It processes information from the ears and eyes. It has a role in pain control.

Hindbrain: The HINDBRAIN is made up of the MYELENCEPHALON and also the METENCEPHALON.

Myelencephalon: MYELENCEPHALON is also known as the MEDULLA or the MEDULLA OBLONGATA.

Metencephalon: METENCEPHALON: This is the PONS and the CEREBELLUM.

Cerebellum: CEREBELLUM: Coordinates motor activities. Allows for smooth and precise movements.

Cerebellum: Cerebellum means “small brain.” Part of the lower brain located in the back of the head that coordinates fine motor movement and muscle activity; balance, accuracy and muscle coordination. People with damaged cerebellums suffer from a lack of orientation, coordination, and balance; they are unable to walk, talk, eat and perform self-care tasks. It is a large structure at the base of the brain stem.

Pons: PONS: The bulge on the surface of the brain stem that houses part of the RETICULAR ACTIVATING SYSTEM: Regulates sleep and functions of the autonomic nervous system, activities not under conscious control.

Reticular Activating System: It is also known as Reticular Formation. Reticular means “net.” It is a net that catches nerve impulses. It regulates the activity level of the body especially of the autonomic nervous system activities. It is located at the base of the brain inside the spinal cord.

Reticular Activating System: RETICULAR FORMATION: Nerve impulses from brain to body and body to brain pass through the RAS. It reads the level of activity throughout the whole system. It regulates breathing and how alert or how sleepy we are. Drugs used in surgery dramatically slow down the RAS blocking pain signals Boring lectures put people to sleep!!! A blow to the head cuts off the RAS creating unconsciousness.

Brain Stem: BRAIN STEM: composed of midbrain and hindbrain: Responsible for subconscious body processes such as: Heartbeat, respiration, blood pressure, digestion, etc…

Brain Stem: The brain stem contains nerve fibers that connect the two hemispheres of the cerebrum to the spinal cord. It is the lower extension of the brain where it connects to the spinal cord. It has evolved very little over time. Controls subconscious activities such as breathing, sleeping, waking, blood pressure, digestion, heart rate, and blood sugar. It regulates functions that are necessary for survival and for arousal (being awake and alert). It is made up of areas known as the Midbrain and the Hindbrain.

Limbic System: LIMBIC SYSTEM: The lower brain area whose structures are involved in basic emotions and memory. Regulates sex, rage, fear, etc… It is made up of the AMYGDALA and the HIPPOCAMPUS.

Amygdala: AMYGDALA: The part of the Limbic System that is primarily responsible for emotions. Ex: aggression.

Hippocampus: HIPPOCAMPUS: Part of the Limbic System that enables people to form memories, especially recent memory.