Systems Physiology - AP Biology

Mast cells contains secretory granules, rich in histamine and other hormonal mediators, that promote inflammation and other allergy symptoms in response to antigen exposure.

Germ layers are primary layers of cells that form during embryogenesis. In mammals, they are the endoderm, ectoderm, and mesoderm. In embryo development, the germ layers differentiate during gastrulation.

The mesoderm is a primary germ layer that forms during gastrulation. The mesoderm develops into most of the organ systems of the human body, including the muscular system, circulatory system, and excretory system.

A woman is said to be “full term” when she is at 39 to 41 weeks of pregnancy. Medical intervention to induce labor during this time is not ideal.

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.

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.

The correct answer is dura mater, arachnoid and lastly the pia mater. The meninges surround the brain and spinal cord in the central nervous system and are made up of three layers. The outermost layer is the dura mater, beneath it lies the arachnoid and below that is the pia mater.

During the generation of an action potential, the cell will undergo two refractory periods. The first is referred to as the absolute refractory period, during which no stimulus, regardless of size, will generate another action potential. This is followed by the relative refractory period, during which an action potential will be generated only if an abnormally large stimulus is encountered. During the relative refractory period, the cell is hyperpolarized due to the removal of potassium ions from the cell interior, which results in a more negative membrane potential than the cell would have at rest.