Chapter 29 Biology Notes By Sean Going

Central Nervous System

The Central Nervous System is a complex of nerve tissues which controls the actions of the body. This is the part of the nervous system which involves the brain and spinal cord. It uses information from and runs the actions of entire body.

Peripheral Nervous System

The Peripheral Nervous System consists of the nerves outside of the brain and the spinal cord. The main function of this system is to connect the CNS to other parts of the body. This system is not protected by the spine like the CNS so it is prone to toxins.

Somatic Nervous System

The Somatic Nervous system is the part of the Peripheral Nervous System which controls voluntary muscular movements. This consists of afferent, efferent, sensory and motor nerves.

Autonomic Nervous System

The Autonomic Nervous System is the part of the Peripheral System which controls involutary movements. This system controls organs, digestion, heart function, etc. This consists of two subsystems which are the Sympathetic and Parasympathetic systems. The primary function for the Sympathetic System is the flight or fight reaction, but also is always active in homeostasis. The Parasympathetic System controls many of the actions of the body when it is resting.

Sensory Neuron

The sensory neurons are nerve cells within the nervous system which turn external stimuli into internal impulses in the body. For example, if there is a stimuli detected by these neurons the signal is sent to the brain to do an action to combat said stimuli.


An internueron is a neuron that transmits impulses between other neurons, especially as part of a reflex arc.

Motor Neurons

A motor neuron is a neuron whose cell body is located in the spinal cord and whose axon projects outside of the spinal cord to directly or indirectly control effector organs, mainly muscles and glands.

Neuromuscular Junction

A Neuromuscular Junction is a chemical synapse formed by the contact between a motor neuron and a muscle fiber. At this Junction the motor neuron can send a signal to the muscle fiber, causing muscle contraction.


Acetylcholine is an organic chemical that functions in the brain and body of many animals as a neurotransmitter, a chemical released by nerve cells to send signals to other cells. This is the chemical used at the previously spoken about Neuromuscular Junction.

Norepinephrine and epinephrine

Norepinephrine and Epinephrine are two organic chemicals that act as hormones and neurotransmitters in the body. Both of these chemicals are important in the fight or flight response, for they are released during it.


A synapse is a junction between two nerve cells, which contains a small gap which impulses pass by diffusion through a neurotransmitter. This allows a neuron to pass an electrical or chemical impulse to another neuron.

White Matter

White matter is bundles of axons which connect grey matter areas of the brain to each other and carry nerve impulses between neurons. This actively affects learning and brain functions.

Grey Matter

Grey matter is a key component in the central nervous system which consists of neuronal cell bodies, neuropil, glial cells, synapses and capillaries. This is different from white matter because grey matter mainly has nerve cells where white matter mainly has axons.

Cerebral Cortex

The Celebral Cortex is composed of the outer layer of the celebrum, consisting of folded grey matter and plays a signifigant role in consciousness. This plays a key role in memory, attention, perception, awarness thought and language as well.

Lobes of the Brain

The Brain has many different lobes, which do different functions. Some of these lobes are the frontal lobe, pariental lobe, occipital lobe and the pariental lobe. All are very important to the brain and its function..

Limbic System

The Lymbic system is set of brain structures on either side of the thalamus, which is directly under the celebrum. It consists of the telencephalon, diencephalon, mesencephalon, olfactory bulbs, hippocampus, hypothalamus, amygdala, anterior thalamic nuclei, fornix, columns of fornix, mammillary body, septum pellucidum, habenular commissure, cingulate gyrus, parahippocampal gyrus, limbic cortex, and limbic midbrain areas. This supports functions like emotion, motivation, behavior and long term memory.

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