Nervous System

Two almond-shaped nuclei deep within the temporal lobe. They are involved in decision-making, memory, and emotional responses; particularly negative emotions.

Amygdala

The autonomic nervous system is responsible for coordinating involuntary behaviors such as heart rate, breathing, and digestion. This system allows these important functions to take place without conscious thought, so they work automatically.

Auntonomic Nervous System (ANS)

The axon is a tail-like structure of the neuron which functions in carrying signals away from the soma to the end of the neuron, for the purpose of transmitting signals to other neurons.

Axon

It is the most complex organ in the human body. The brain is the central control module of the body and coordinates activity.

Brain

This small area on the left side of the brain (sometimes on the right in left-handed individuals) is important in language processing. When damaged, an individual finds it difficult to speak but can still understand speech. Stuttering is sometimes associated with an underactive Broca's area.

Broca's Area

It is mostly involved in precise motor control, but also in language and attention. If the cerebellum is damaged, the primary symptom is disrupted motor control, known as ataxia.

Cerebellum

It is a broad band of nerve fibers that join the left and right hemispheres. It is the largest white matter structure in the brain and allows the two hemispheres to communicate. Dyslexic children have smaller corpus callosums; left-handed people, ambidextrous people, and musicians typically have larger ones.

Corpus Callosum

The cranial nerves primarily coordinate the muscle and sense receptors of the head and neck. These nerves are different to the spinal nerves as they do not enter through the spinal cord to reach the brain, instead, they are directly linked to the brain. Cranial nerves allow sensory information to transmit from the organs of the brain (ears, eyes, nose, and mouth), as well as conveying motor information from the brain to these organs.

Cranial Nerves

The dendrites of the neurons are tree-root shaped, located at the end of the neuron. Their function is to receive and pass on information through their synapses to other neurons nearby.

Dendrites

Positioned at the front of the brain, the frontal lobe contains the majority of dopamine-sensitive neurons and is involved in attention, reward, short-term memory, motivation, and planning.

Frontal Lobe

The PNS is all the nerves that branch out from the CNS components and extend to other parts of the body - to the sense organs, muscles, and glands. The PNS connects the CNS to the rest of the body. The primary function of the peripheral nervous system is to connect the brain and spinal cord to the rest of the body and the external environment. The peripheral nervous system transmits information to and from the CNS.

Function of the PNS

It controls our thoughts, movements, emotions, and desires. It also controls our breathing, heart rate, the release of some hormones, body temperature, and much more.

Functions of the CNS

Sitting just above the brain stem and roughly the size of an almond, the hypothalamus secretes a number of neuro-hormones and influences body temperature control, thirst, and hunger.

Hypothalamus

Extending below the skull, it is involved in involuntary functions, such as vomiting, breathing, sneezing, and maintaining the correct blood pressure.

Medulla oblangata

It is a protective triple-layered membrane that houses the brain and spinal cord.

Meninges

also known as efferent neurons, they transmit signals from the CNS to skeletal and muscle to either directly or indirectly control muscle movements. Motor neurons allow us to act in response to external stimuli. For instance, during tasting a food, the sensory neurons will send this information to the brain. The brain will then transmit signals through the motor neurons to encourage the mouth, jaw, and teeth to continue eating the food.

Motor Neurons

The nerve cells (or neurons) are the information processing units of the brain that are responsible for sending, receiving, and transmitting signals throughout the body. The neurons are essentially the cells which make up the central nervous system and the peripheral nervous system.

Neurons

It is the visual processing region of the brain and it houses the visual cortex.

Occipital Lobe

The parasympathetic nervous system relaxes the individual once the emergency has passed. The parasympathetic system aims to maintain normal bodily functions by decreasing activity/maintaining it. When this happens, the system will reduce the heart rate, stop the body from sweating, decrease blood flow, and constrict the pupils - allowing us to reach a state of rest.

Parasympathetic Nervous System

It integrates sensory information including touch, spatial awareness, and navigation. Touch stimulation from the skin is ultimately sent to the parietal lobe. It also plays a part in language processing.

Parietal Lobe

also known as afferent neurons, they send information to the CNS from the internal organs (glands, muscle, and skin) or from external stimuli (e.g. through sound, heat, touch and light). For instance, when touching a rough surface, this information will be transmitted through the sensory neurons to the brain.

Sensory Neurons

The sympathetic nervous system mostly comes into play during times when the body feels it needs to respond to threatening stimuli. This response is called the fight-or-flight response. During a threatening situation, this system will respond by increasing heart rate, activate sweat glands, increase blood flow, and dilate the pupils. It slows bodily processes that are less important in emergencies such as digestion.

Sympathetic Nervous System (SNS)

It is the part of the brain that deals with processing sensory input and assigning it emotional meaning.

Temporal Lobe

It is positioned in the center of the brain, the thalamus receives sensory and motor input and relays it to the rest of the cerebral cortex. It is involved in the regulation of consciousness, sleep, awareness, and alertness.

Thalamus

The SNS controls voluntary actions such as walking. The ANS is responsible for the control of vital functions such as heart beat and breathing.

What is the difference between the somatic nervous system (SNS) and autonomic nervous system (ANS)?