The soma, or cell body, of a neuron contains the nucleus and other essential organelles necessary for the cell's function. It integrates incoming signals from dendrites and initiates an action potential if the threshold is reached.
Question 2
A signal is transmitted down the axon of a nerve cell.
Missing Word
axon
The axon is a long, slender projection of a nerve cell that conducts electrical impulses, known as action potentials, away from the cell body. These signals are transmitted to other neurons or target cells at synapses located at the axon terminals.
Question 3
The subarachnoid space is filled with cerebrospinal fluid.
Missing Words
subarachnoid, space
The subarachnoid space, located between the arachnoid mater and pia mater, is filled with cerebrospinal fluid (CSF). CSF cushions the brain and spinal cord, provides nutrients, and removes waste products, contributing to the overall health and function of the central nervous system.
Question 4
The blood-brain barrier prevents access of microbes in the blood from gaining access to the central nervous system.
Missing Word
blood-brain barrier
The blood-brain barrier (BBB) is a highly selective semipermeable border of endothelial cells that prevents solutes in the circulating blood from non-selectively crossing into the extracellular fluid of the central nervous system where neurons reside. This barrier protects the brain from pathogens and toxins, while allowing essential nutrients to pass through.
Question 5
The meninges are a set of membranes that cover and protect the brain.
Missing Word
meninges
The meninges are three layers of protective membranes (dura mater, arachnoid mater, and pia mater) that surround the brain and spinal cord. They provide physical stability and protection against trauma.
Question 6
The form of meningitis that can cause epidemics is caused by the pathogen Neisseria meningitidis.
Missing Words
Neisseria, meningitidis
Neisseria meningitidis is a bacterium that can cause meningococcal meningitis, a severe and rapidly progressing infection of the meninges. Its ability to spread through respiratory droplets makes it capable of causing epidemics, particularly in crowded environments.
Question 7
The symptoms of tetanus are caused by the neurotoxin tetanospasmin.
Missing Word
tetanospasmin
Tetanospasmin is a potent neurotoxin produced by Clostridium tetani. This toxin blocks the release of inhibitory neurotransmitters, leading to uncontrolled muscle contractions and the characteristic symptoms of tetanus.
Question 8
Hansen’s disease is another name for leprosy.
Missing Word
Hansen’s disease
Hansen's disease, caused by Mycobacterium leprae, is a chronic infectious disease affecting the skin, peripheral nerves, upper respiratory tract, eyes, and testes. The term 'Hansen's disease' is often preferred to reduce stigma associated with the term 'leprosy'.
Question 9
Botulism prevents the release of the neurotransmitter acetylcholine.
Missing Word
acetylcholine
Botulism toxin, produced by Clostridium botulinum, blocks the release of acetylcholine at neuromuscular junctions. Acetylcholine is a critical neurotransmitter for muscle contraction, and its blockage leads to flaccid paralysis.
Question 10
Tetanus is a neurological disease that can be prevented with the DTaP vaccine.
Missing Word
Tetanus
Tetanus, caused by Clostridium tetani, is a serious neurological disease characterized by muscle spasms. The DTaP vaccine provides protection against tetanus by stimulating the production of antibodies against the tetanus toxin.
Question 11
Tetanus patients exhibit opisthotonos when muscle spasms causes them to arch their backs.
Missing Word
opisthotonos
Opisthotonos is a severe form of muscle spasm seen in tetanus where the back arches severely. This is due to the effects of tetanospasmin on the nervous system, causing simultaneous contraction of agonist and antagonist muscles.
Question 12
The rogue form of the prion protein is called PrPSc.
Missing Word
PrPSc
PrPSc is the misfolded, infectious form of the prion protein (PrPC). PrPSc can induce normal PrPC to misfold, leading to the accumulation of PrPSc aggregates and causing transmissible spongiform encephalopathies.
Question 13
Dogs are the most common reservoir for the rabies virus worldwide.
Missing Word
Dogs
Dogs are the primary reservoir for the rabies virus in many parts of the world, particularly in regions where canine vaccination programs are not widespread. Transmission to humans typically occurs through bites from infected dogs.
Question 14
Jonas Salk was the scientist who developed the inactivated polio vaccine.
Missing Words
Jonas, Salk
Jonas Salk developed the first inactivated polio vaccine (IPV), which uses killed poliovirus to stimulate an immune response. This vaccine significantly reduced the incidence of polio and paved the way for global eradication efforts.
Question 15
Chronic wasting disease is a prion disease of deer and elk.
Missing Word
Chronic wasting disease
Prion diseases, like chronic wasting disease (CWD), are caused by misfolded proteins called prions. CWD specifically affects cervids such as deer and elk, leading to neurological damage.
Question 16
The rogue form of prion protein exists primarily in the beta sheet conformation.
Missing Words
beta, sheet
Prions are characterized by a conformational change from a normal alpha-helical structure to a beta-sheet rich structure. This altered conformation promotes aggregation and resistance to degradation, leading to disease.
Question 17
The capsule is the main virulence factor of Cryptococcus neoformans.
Missing Word
capsule
Cryptococcus neoformans' capsule is a major virulence factor because it inhibits phagocytosis by immune cells. The capsule's polysaccharide composition contributes to its antiphagocytic properties.
Question 18
The drug of choice for fungal infections of the nervous system is Amphotericin B.
Missing Word
Amphotericin B
Amphotericin B is an antifungal drug that binds to ergosterol in fungal cell membranes, disrupting their integrity. It is often used to treat serious systemic fungal infections, including those affecting the nervous system, due to its broad spectrum of activity.
Question 19
The larval forms of a tapeworm are known as cysticerci.
Missing Word
cysticerci
Cysticerci are the larval stage of some tapeworms that form in the intermediate host's tissues. These larvae contain an invaginated scolex that can develop into an adult tapeworm upon ingestion by the definitive host.
Question 20
Winterbottom’s sign appears as swollen lymph nodes at the back of the neck in early African trypanosomiasis.
Missing Word
Winterbottom’s
Winterbottom's sign, characterized by swollen posterior cervical lymph nodes, is a clinical indicator of early-stage African trypanosomiasis. This swelling results from the parasite's presence and the host's immune response in the lymphatic system.
Question 21
West African trypanosomiasis causes a chronic form of sleeping sickness.
Missing Word
West
West African trypanosomiasis, caused by Trypanosoma brucei gambiense, typically progresses slowly, leading to a chronic form of sleeping sickness. East African trypanosomiasis, in contrast, progresses more rapidly.
Question 22
The definitive host for Toxoplasma gondii is cats.
Missing Word
cats
Toxoplasma gondii undergoes sexual reproduction in cats, making them the definitive host. Other animals, including humans, can serve as intermediate hosts, where the parasite forms tissue cysts.
Question 23
Trypanosomes can evade the immune response through antigenic variation.
Missing Word
antigenic
Trypanosomes evade the host immune response through antigenic variation, where they change the variant surface glycoprotein (VSG) on their surface. This constant switching of VSG allows them to avoid antibody recognition and clearance.