Vertebrate Nervous Systems

Distinguish between the functions of the autonomic nervous system and the somatic nervous system.

Somatic nervous system – carries signal to skeletal muscles, mainly in response to external stimuli, primarily voluntary but also mediated by the spinal cord and lower brain.

Autonomic nervous system – regulates the internal environment by controlling organs of the gastrointestinal, cardiovascular, excretory and endocrine systems, generally involuntary.

Describe the embryonic development of the vertebrate brain.

Begins from the neural tube as three bulges: the forebrain, midbrain and hindbrain. These then become the telencephalon and diencephalons (from the forebrain), midbrain, and the metencephalon and myelencephalon (from the hindbrain). Telencephalon becomes the cerebrum with two hemispheres and the diencephalon becomes the thalamus, epithalamus and hypothalamus. The midbrain and hindbrain regions become the brainstem and the cerebellum.

Describe the structures and functions of the following brain regions: medulla oblongata, pons, midbrain, cerebellum, thalamus, epithalamus, hypothalamus, and

cerebrum.

Medulla develops from the myelencephalon and controls visceral functions (e.g., breathing, heart and blood vessel activity, swallowing, digestion)

Pons develops from the metencephalon and controls some of the above functions and also regulates breathing centers in the medulla.

Midbrain – integration of several types of sensory information

Cerebellum – develops from the metencephalon, and functions in coordination and error checking during motor, perceptual and cognitive functions

Thalamus – from the diencephalon, main input center of sensory information

Epithalamus – from the diencephalons, includes choroids plexus, produces cerebrospinal fluid and forms the pineal gland

Hypothalamus – from the diencephalons, helps maintain homeostasis, control release of hormones from pituitary

Cerebrum – from the telencephalon, sensory input and integration of most brain signals to their response.

Describe the specific functions of the reticular system.

Regulates sleep and arousal, acts as a sensory filter by selecting which information reaches the cortex, prevents sensory overload.

Describe the specific functions of the brain regions associated with language, speech, emotions, and memory.

Language – processed by multiple regions of the cortex depending on if it is just hearing words, seeing words, speaking words or generating words or the combination of all of these. Broca’s area is active during generation of speech, Wernicke’s region is important for understanding words, reading words uses the visual cortex and Broca’s area. Frontal and temporal areas are necessary for meaning of words.

Emotions – processed by the limbic system, which includes the hippocampus, olfactory cortex, thalamus and hypothalamus. Also the amygdala is important in attaching emotional content to facial expressions.

Memory – sensory and motor association areas of the cerebral cortex, amygdala and hippocampus.

Describe our current understanding of human consciousness.

Consciousness is our ability to experience ourselves not only as sensing, acting and feeling beings, but also our ability of thinking about the past and the future. One model suggests a scanning mechanism that repetitively sweeps across the brain to unite many of the disparate processes that represent consciousness into a unified mechanism.