Chapter 45

What are the components of the autonomic nervous system (ANS)?

The ANS includes parts of the central and peripheral nervous system. It controls involuntary functions and is composed of two divisions.

What are the two divisions, which work in opposition, of the autonomic nervous system (ANS)?

1. Sympathetic (nervous system) — fight or flight

2. Parasympathetic (nervous system) — rest and digest

Where does the CNS develop from?

It develops from the neural tube (dorsal hollow nerve cord) of an embryo.

What does the anterior part of the neural tube develop into?

The hindbrain, midbrain, and forebrain.

What does the rest of the neural tube develop into (the CNS, hindbrain, midbrain, and forebrain are already developed)?

The rest of the neural tube gives rise to the spinal cord.

What type of structures does the midbrain develop?

The midbrain develops structures that integrate information from the senses and coordinate motor responses.

What does the hindbrain develop into?

The pons, medulla, and cerebellum.

What do the medulla and pons control?

They control physiological functions like breathing.

What does the cerebellum do?

It coordinates muscle activity and maintains balance.

What do the midbrain, medulla, and pons make up?

The brainstem.

What is the significance of the brainstem regarding the travel of information?

All information traveling between the spinal cord and higher brain areas must pass through the brainstem.

The forebrain develops into which two regions?

The diencephalon and telencephalon (cerebrum).

The diencephalon is composed of which two parts?

Thalamus and hypothalamus.

What is the telencephalon (cerebrum) composed of?

Cerebral hemispheres; a right and left hemisphere.

What is the outer layer of the telencephalon?

It is the cerebral cortex, a thin layer rich in cell bodies (gray matter outside and white matter inside).

The cerebral cortex has a large surface area; it is folded into ridges and valleys. What are the ridges and valleys called?

The ridges are gyri, and valleys are sulci.

What do the folds in the cerebral cortex do?

The folds, also called convolutions, allow the large surface of the cortex to fit in the skull.

What are the lobes of the brain?

1. Frontal

2. Parietal

3. Occipital

4. Temporal

5. Insular

(Different functions are localized in particular areas of the five cerebral lobes. Look at picture)

What does the left hemisphere of the telencephalon do?

It mostly controls the right side of the body.

What does the right hemisphere of the telencephalon do?

It controls the left side of the body except for the head. In the head, right control right, left controls left.

At the core of the forebrain (diencephalon), what does the thalamus do?

It communicates sensory information to the cerebral cortex.

At the core of the forebrain (diencephalon), what does the hypothalamus do?

It regulates homeostatic functions.

What surrounds the diencephalon?

Phylogenetically older structures of the telencephalon called the limbic system.

What is the limbic system responsible for?

It is responsible for instincts, long term memory, formation, drives such as hunger & thirst, sexual behavior, and emotions.

What is the amygdala responsible for?

It is involved in memories of fear and our responses to fear.

What is the hippocampus responsible for?

Memory function; transferring short-term memory to long-term memory.

Gymnasts rely on parts of their brains to execute their routines precisely. The region of the brain that is most important for coordinating motor commands and maintaining balance is the _______, which develops from the embryonic _______.

a. cerebrum; forebrain
b. cerebral cortex; hindbrain
c. cerebellum; hindbrain
d. right cerebral hemisphere; midbrain
e. diencephalon; forebrain

c. cerebellum; hindbrain

Which statement about the human brain is true?

a. The increase in brain size in humans is due largely to an increase in the size of the cerebellum.
b. Humans have a much larger brain than would be predicted by their body size.
c. Humans have the heaviest brain of all mammals.

b. Humans have a much larger brain than would be predicted by their body size. (The gyri and sulci give the brain the ability to fit into the skull.)