Nervous System - AP Biology

Neurotransmitters from presynaptic cells are received by the dendrites of postsynaptic cells. There are myriad dendrites on each neuron that then propagate this signal to the soma (or cell body), allowing the signal to be passed down the axon to another neuron.

The axon carries action potentials away from the cell body of a neuron via a sequence of continuous depolarization. The cell body, or soma, however, is the site of neurotransmitter production and the location of the nucleus and other organelles. Every single neuron contains only one axon.

The tiny gaps in between myelin sheaths are referred to as nodes of Ranvier. The action potential will jump from node to node as it moves down the axon.

If an axon existed without these gaps (the entire length was covered in myelin), it would be unable to conduct an action potential.

A neuron receives input from other neurons at the dendrites. Neurotransmitters released by other neurons bind to receptors on the dendrites, which carry the signal to the cell body. The signal is then amplified in the cell body before being transferred to the axon. Once the signal transitions to the axon, it is considered an action potential. The signal eventually reaches the end of the axon, where the synaptic vesicles are located, and stimulates release of neurotransmitters to the next neuron's dendrites.

Neurons have many dendrites, one cell body, and a single axon with several terminal branches. A dendrite receives an external stimulus and causes an electrical disturbance in the cell body. This electrical disturbance is transmitted to the axon, where an action potential is generated if the stimulus is large enough. The action potential is propagated through the axon and is transmitted to a neighboring neuron at the synapse.

A large enough electrical disturbance will generate an action potential in the axon, but no magnitude of stimulus can create an action potential in the dendrites. Neurons do contain multiple dendrites, but they only contain one cell body and one axon. Finally, neurons transmit electrical signals to other neurons at the synapse, not at the cell body.

There are two types of synapses: chemical and electrical. Chemical synapses use chemical signals called neurotransmitters to transmit nerve signals between neurons, whereas electrical synapses use electrical signals. These electrical signals are transmitted through a gap junction that connects adjacent neurons. Intercalated discs in cardiac muscle contain gap junctions for the purpose of propagating electrical signals to cause systole.

While both oligodendrocytes and Schwann cells produce myelin sheaths that insulate nervous system signals, only the Schwann cells are found in the peripheral nervous system.

All other cells listed are found only in the central nervous system. Microglia act as immune cells within the cerebrospinal fluid, since lymphocytes are barred entry by the blood-brain barrier. Astrocytes support the neural cells and provide nutrients. Ependymal cells are responsible for secreting cerebrospinal fluid.

The correct answer is Schwann cells. Schwann cells are cells that produce the myelination present on the outer covering of the axon of the neuron. This lipid-rich material helps facilitate the movement of the action potential along the axon from the axon hillock to the axon terminal branches.

Folds are present in the human brain due to the rapid evolution of brain-related tasks while the skull shape and size remained relatively constant; therefore, folds are present as modifications to limited surface-area-to-volume ratios in the skull cavity.

The cerebellum is mainly responsible for fine tuning the motions of the body, including balance and coordination. As a result, damage to this region would cause difficulty walking straight and maintaining balance.

The medulla oblongata is in the lower half of the brainstem. It controls a variety of functions, mostly involuntary and essential. Heart beat, breathing, and blood pressure are controlled in the medulla oblongata, as is the vomiting reflex.

Speech is controlled by Broca's area, which is located in the frontal lobe of the cerebrum.

Each answer corresponds to one lobe of the cerebrum. The frontal lobe is responsible for conscious thought, as well as many other functions. The parietal lobe is responsible for integrating tactile information. The temporal lobe has the functions of interpreting smell and sound. The occipital lobe is associated with processing visual information.

The eye is divided into two chambers by the lens: the anterior and posterior chambers. The anterior chamber is filled with aqueous humor, while the posterior chamber is filled with vitreous humor. Aqueous humor nourishes the eye and maintains intraocular pressure. Aqueous humor is also important in the refraction of light, which allows humans to distinguish clear images and colors.

Hippocratic and Galen humor do not exist. Hippocrates and Galen were two ancient physicians who would use the four humors (yellow bile, black bile, phlegm, and blood) to diagnose and treat patients.

Unmyelinated nervous system components make up grey matter, while myelinated axons make up white matter. The cerebral cortex on the surface of the brain contains unmyelinated neural tissue, namely the cell bodies of neurons in the central nervous system. This region is rich in connections. Below its surface lie many myelinated axon tracts to inner nuclei, the cerebellum, other areas of the cortex, and the spinal cord.

In the blind spot, there is a lack of photoreceptors as the optic nerve exits the optic disk. We normally overcome this automatically when our brains use the information of the surrounding visual field and "fills in" the blind spot.

The central nervous system consists of the brain and spinal cord. The peripheral nervous system consists of any nerves or ganglia, not including the brain and spinal cord. The prefrontal cortex is a structure in the cerebrum of the brain, and is thus part of the central nervous system.

General nerves throughout the body are part of the peripheral nervous system.

The spinal cord and vertebrae is broken down into four regions: cervical, thoracic, lumbar, and sacral. There are seven cervical vertebrae, twelve thoracic vertebrae, five lumbar vertebrae, and five sacral vertebrae. Cervical vertebrae are located in the neck, thoracic vertebrae in the trunk or upper back, lumbar vertebrae in the lower back, and sacral vertebrae in the gluteal region. The sacral vertebrae are fused into a single unit known as the sacrum.

The spinal cord consists of functional horns that help send information to the brain, as well as to the parts of the body. The dorsal horns send sensory information to the brain, while the ventral horns contain motor neurons.

The correct order of the spinal meninges from superficial to deep (outside to inside) is dura mater, arachnoid mater, and pia mater. The dura mater is the most outer layer that is closely associated with the skill and vertebral column. Deep to the dura mater is the arachnoid mater, which contains the cerebrospinal found in the subarachnoid space. Underneath the subarachnoid space lies the pia mater, which is very closely associated with the brain and spinal cord.