Anatomy Lecture Exam 2 Clinical Application

Which type of neuron, based on its shape, is best suited for relaying information directly from one neuron to another?

Bipolar cells, because they have one dendrite that receives input and one axon that provides output, would be a direct relay between two other cells.

If innervation to the adrenal medulla were disrupted, what would be the physiological outcome?

Damage to the innervation of the adrenal medulla wouldprevent the adrenal glands from responding to the hypothalamus during the fight-or-flight response. Therefore, the response would be reduced.

Why is the receptor the important element determining the effect a neurotransmitter has on a target cell?

Different neurotransmitters have different receptors

Why do the anatomical inputs to the cerebellum suggest that it can compare motor commands and sensory feedback?

A copy of descending input from the cerebrum to the spinal cord, through the pons, and sensory feedback from the spinal cord and special senses like balance, through the medulla, both go to the cerebellum. It can therefore send output through the midbrain that will correct spinal cord control of skeletal muscle movements.

Explain why someone with a parathyroid gland tumor might develop kidney stones

A parathyroid gland tumor can prompt hypersecretion of PTH. This can raise blood calcium levels so excessively that calcium deposits begin to accumulate throughout the body, including in the kidney tubules, where they are referred to as kidney stones.

Sensory fibers, or pathways, are referred to as "afferent." Motor fibers, or pathways, are referred to as "efferent." What can you infer about the meaning of these two terms (afferent and efferent) in a structural or anatomical context?

Afferent means "toward," as in sensory information traveling from the periphery into the CNS. Efferent means "away from," as in motor commands that travel from the brain down the spinal cord and out into the periphery.

A semiconscious young woman is brought to the hospital by friends after falling from a rood. She did not lose consciousness immediately, and she was initially lucid. After a while, though, she became confused and then unresponsive. What is a likely explanation of her condition?

An intracranial hemorrhage

Compare and contrast endocrine and exocrine glands

Endocrine glands are ductless. They release their secretion into the surrounding fluid, from which it enters the bloodstream or lymph to travel to distant cells. Moreover, the secretions of endocrine glands are hormones. Exocrine glands release their secretions through a duct that delivers the secretion to the target location. Moreover, the secretions of exocrine glands are not hormones, but compounds that have an immediate physiologic function. For example, pancreatic juice contains enzymes that help digest food.

Why is foot care extremely important for people with diabetes mellitus?

Excessive blood glucose levels damage the blood vessels and nerves of the body's extremities, increasing the risk for injury, infection, and tissue death. Loss of sensation to the feet means that a diabetic patient will not be able to feel foot trauma, such as from ill-fitting shoes. Even minor injuries commonly lead to infection, which , can progress to tissue death without proper care, requiring amputation.

Define hyperthyroidism and explain why one of its symptoms is weight loss

Hyperthyroidism is an abnormally elevated blood level of thyroid hormones due to an overproduction of T3 and T4. An individual with hyperthyroidism is likely to lose weight because one of the primary roles of thyroid hormones is to increase the body's basal metabolic rate, increasing the breakdown of nutrients and the production of ATP.

As the aroma of freshly brewed coffee drifted by dozing Joe's nose, his mouth began to water and his stomach began to rumble. Explain his reactions in terms of ANS activity.

If we are hungry or feel the urge to eat, just the sight, smell or thought of food will cause our digestive system to signal the brain to get all systems prepared for the entry of food. This causes the muscles that line the stomach and intestines to start moving and release digestive fluids, which in turn interact with the air and fermented gas floating inside our intestinal system (not too appetizing to think about while on the buffet line). Most often this process is silent, but does have the potential to play the "gastric symphony," otherwise known in medical circles as "borborygmi."

What responses are generated by the nervous system when you run on a treadmill? Include an example of each type of tissue that is under nervous system control.

Running on a treadmill involves contraction of the skeletal muscles in the legs (efferent somatic motor), increase in contraction of the cardiac muscle of the heart (efferent autonomic motor), and the production and secretion of sweat in the skin to stay cool (sensation of temp = afferent visceral sensory, sweat gland activation = efferent autonomic motor).

Seasonal affective disorder (SAD) is a mood disorder characterized by, among other symptoms, increased appetite, sluggishness, and increased sleepiness. It occurs most commonly during the winter months, especially in regions with long winter nights. Propose a role for melatonin in SAD and a possible non-drug therapy

SAD is thought to occur in part because low levels and duration of sunlight allow excessive and prolonged secretion of melatonin. Light therapy—daytime exposure to very bright lighting—is one common therapy.

Mr. Harrison is an 82-year-old bedridden gentlemen who has discovered a new interest in learning about his body. While being tended by the visiting nurse, he remarks that the supporting cells in nervous tissue (such as Schwann cells and oligodendrocytes) act like the rubber coating around household wiring. What does he mean by this analogy?

Schwann cells and oligodendrocytes deposit a fatty coat called myelin around axons. Like the rubber coat around household wires, myelin acts as an electrical insulator.

During John's checkup, one year after an accident severed his right accessory nerve, the physician noted severe muscle atrophy. What two prominent muscles have been affected?

Sternocleidomastoid and trapezius muscles

Compare and contrast the anatomical relationship of the anterior and posterior lobes of the pituitary gland to the hypothalamus

The anterior lobe of the pituitary gland is connected to the hypothalamus by vasculature, which allows regulating hormones from the hypothalamus to travel to the anterior pituitary. In contrast, the posterior lobe is connected to the hypothalamus by a bridge of nerve axons called the hypothalamic-hypophyseal tract, along which the hypothalamus sends hormones produced by hypothalamic nerve cell bodies to the posterior pituitary for storage and release into the circulation.

Testing for neurological function involves a series of tests of functions associated with the cranial nerves. What functions, and therefore which nerves, are being tested by asking a patient to follow the tip of a pen with their eyes?

The contraction of extraocular muscles is being tested, which is the function of the oculomotor, trochlear, and abducens nerves.

In the context of a lioness hunting on the savannah, why would the sympathetic system not activate the digestive system?

Whereas energy is needed for running away from the threat, blood needs to be sent to the skeletal muscles for oxygen supply. The additional fuel, in the form of carbohydrates, probably wouldn't improve the ability to escape the threat as much as the diversion of oxygen-rich blood would hinder it.

Medical practice is paying more attention to the autonomic system in considering disease states. Why would autonomic tone be important in considering cardiovascular disease?

Within the cardiovascular system, different aspects demonstrate variation in autonomic tone. Heart rate is under parasympathetic tone, and blood pressure is under sympathetic tone. Pharmaceuticals that treat cardiovascular disorders may be more effective if they work with the normal state of the autonomic system. Alternatively, some disorders may be exacerbated by autonomic deficits and common therapies might not be as effective.

Derek got hit in the back of neck with a baseball, and now he can't shrug one shoulder. Which cranial nerve is involved?

cranial nerve XI - accessory nerve

Joseph, a man in his early 70's, was having problems chewing his food. He was asked to stick out his tounge. It deviated to the right side, and its right side was quite wasted. What cranial nerve was inpaired?

hypoglossal (XII)

Name the target tissues for prolactin

mammary glands

Multiple sclerosis is a demyelinating disease affecting the CNS. What type of cell would be the most likely target of this disease?

oligodendrocytes

Distinguish between the effects of menopause and andropause on fertility.

Menopause occurs as the result of a progressive decline in the function of the ovaries, resulting in low estrogen and progesterone levels. Ovulation ceases, and postmenopausal woman can no longer conceive a child. In contrast, andropause is a much more gradual and subtle decline in testosterone levels and functioning. A man typically maintains fertility until very old age, although the quantity, quality, and motility of the sperm he produces may be reduced.

Describe the role of placental secretion of relaxin in preparation for childbirth

Relaxin produced by the placenta is thought to soften and widen the pubic symphysis. This increases the size of the pelvic outlet, the birth canal through which the fetus passes during vaginal childbirth.

Clarence, an elderly man with a history of TIAs, complained to his daughter that he had a severe headache. Shortly thereafter, he lapsed into a coma. At the hospital, he was diagnosed as having a brain hemorrhage. Which part of the brain was damaged by the hemorrhage?

Reticular activating system

Describe several main differences in the communication methods used by the endocrine system and the nervous system

The endocrine system uses chemical signals called hormones to convey information from one part of the body to a distant part of the body. Hormones are released from the endocrine cell into the extracellular environment, but then travel in the bloodstream to target tissues. This communication and response can take seconds to days. In contrast, neurons transmit electrical signals along their axons. At the axon terminal, the electrical signal prompts the release of a chemical signal called a neurotransmitter that carries the message across the synaptic cleft to elicit a response in the neighboring cell. This method of communication is nearly instantaneous, of very brief duration, and is highly specific.

Jason is the star of his hometown ice hockey team. During a game, he is hit with a hockey stick so hard that he hits the ice. When he tries to get up, he is unable to flex his left hip or extend his left knee, but he has no pain. Which nerve has been damaged?

The femoral nerve, which originates at lumbar vertebrae one, two, three, and four experienced trauma by the hockey stick. The femoral motor nerve innervates the rectus femoris muscle, which is only one of four quadriceps muscles that cause both hip joint flexion and knee joint extension. This nerve is also responsible for cutaneous sensation in that area. Jason is not feeling any pain which further indicates femoral nerve damage.

The cardiovascular center is responsible for regulating the heart and blood vessels through homeostatic mechanisms. What tone does each component of the cardiovascular center invoke to keep these two systems in their resting tone?

The heart—based on the resting heart rate—is under parasympathetic tone, and the blood vessels—based on the lack of parasympathetic input—are under sympathetic tone. The vagus nerve contributes to the lowered resting heart rate, whereas the vasomotor nerves maintain the slight constriction of systemic blood vessels.

Damage to internal organs will present as pain associated with a particular surface area of the body. Why would something like irritation to the diaphragm, which is between the thoracic and abdominal cavities, feel like pain in the shoulder or neck?

The nerves that carry sensory information from the diaphragm enter the spinal cord in the cervical region where somatic sensory fibers from the shoulder and neck would enter. The brain superimposes this experience onto the sensory homunculus where the somatic nerves are connected.

Meningitis is an inflammation of the meninges that can have severe effects on neurological function. Why is infection of this structure potentially so dangerous?

The nerves that connect the periphery to the CNS pass through these layers of tissue and can be damaged by that inflammation, causing a loss of important neurological functions.

Why are ganglia and nerves not surrounded by protective structures like the meninges of the CNS?

The peripheral nervous tissues are out in the body, sometimes part of other organ systems. There is not a privileged blood supply like there is to the brain and spinal cord, so peripheral nervous tissues do not need the same sort of protections

When eating food, what anatomical and functional divisions of the nervous system are involved in the perceptual experience?

The sensation of taste associated with eating is sensed by nerves in the periphery that are involved in sensory and somatic functions.

Why can the circle of Willis maintain perfusion of the brain even if there is a blockage in one part of the structure?

The structure is a circular connection of blood vessels, so that blood coming up from one of the arteries can flow in either direction around the circle and avoid any blockage or narrowing of the blood vessels.

Damage to specific regions of the cerebral cortex, such as through a stroke, can result in specific losses of function. What functions would likely be lost by a stroke in the temporal lobe?

The temporal lobe has sensory functions associated with hearing and vision, as well as being important for memory. A stroke in the temporal lobe can result in specific sensory deficits in these systems (known as agnosias) or losses in memory.