By Z. Yasmin. Hebrew College.

The epithelium of the spiral organ consists cells of supporting cells and hair cells (figs order kamagra super 160 mg on-line. The bases of the hair cells are anchored in the basilar membrane, and their tips are embedded in the tectorial membrane, which forms a gelatinous canopy over them. Kardon, Tissues and Organs: A Text-Atlas of Scanning Electron Microscopy. Sensory Organs © The McGraw−Hill Anatomy, Sixth Edition Coordination Companies, 2001 522 Unit 5 Integration and Coordination FIGURE 15. The scala vestibuli and the scala tympani, which contain perilymph, are continuous at the helicotrema. The cochlear duct, which con- tains endolymph, separates the scala vestibuli and the scala tympani. Sounds of low frequency (blue arrow) cause pressure waves of perilymph to pass through the helicotrema and displace the basilar membrane near its apex. Sounds of medium frequency (green arrow) cause pressure waves to displace the basilar membrane near its center. Sounds of high frequency (red arrow) cause pressure waves to displace the basilar membrane near its base. For example, striking the high C on a piano produces a high frequency of sound that has a high pitch. Pathways for Hearing The intensity, or loudness of a sound, is directly related to the amplitude of the sound waves. Sound intensity is measured Sound Waves in units known as decibels (dB). A sound that is barely audible— Sound waves travel in all directions from their source, like rip- at the threshold of hearing—has an intensity of zero decibels. These waves of energy are Every 10 decibels indicates a tenfold increase in sound intensity: characterized by their frequency and their intensity. The fre- a sound is 10 times higher than threshold at 10 dB, 100 times quency, or number of waves that pass a given point in a given higher at 20 dB, a million times higher at 60 dB, and 10 billion time, is measured in hertz (Hz).

Meningitis refers to an mation of the brain due to direct invasion inflammation of the meninges (mem- of an organism buy kamagra super 160mg fast delivery. It may be caused by an branes surrounding the brain and spinal endemic virus, such as the West Nile virus, cord). It can be caused by bacteria, virus- a mosquito-borne virus (Huhn, Sejvar, es, or other organisms. The specific name giv- Gubler, 2001), or it may be secondary to en to the meningitis infection is frequent- another infection, such as measles or ly related to its cause or location. Some individuals with en- instance, cerebral meningitis refers to cephalitis may experience severe head- meningitis of the brain, whereas cere- ache, stiff neck, and coma. There is no brospinal meningitis refers to meningitis of adequate treatment for encephalitis, ex- both the brain and spinal cord. Menin- cept for maintaining comfort and prevent- gococcal meningitis (commonly known as ing complications. The symptoms can spinal meningitis) is caused by a bacterium subside in a few weeks, leaving no perma- that settles in the lining of the throat and nent damage; however, the condition can is spread easily through respiratory secre- also be life-threatening. Some individuals Conditions Affecting the Brain 33 develop irreversible neurological changes gunshot wound). At times, functional impair- with compromised immune systems, are ments in open head injury may be more often the most susceptible to more severe extensive if additional damage is sus- manifestations of these diseases. For example, in addition to the trauma to the brain itself, bone fragments Traumatic Brain Injury from the injury may also lacerate and injure the brain, blood vessels, or Traumatic brain injury is broadly defined meninges (lining surrounding the brain). It is not degenerative, cient force that the brain slams against the is not the result of a disease, and is not other side of the skull or twists within the congenital in origin. Damage to the brain skull, causing shearing of blood vessels or occurs from a blow to the head that is nerve fibers throughout the brain. This is hard enough to cause the brain to move called diffuse axonal injury.

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Treatment with clomiphene kamagra super 160mg mastercard, an antiestrogen that chotropic medications, all of which are associated with a binds to and blocks estrogen receptors, can induce ovula- reduction in dopamine release, resulting in an increased tion in women with endogenous estrogens in the normal PRL secretion. Clomiphene reduces the negative feedback effects hepatic cirrhosis are additional causes of hyperprolactine- of estrogen and thus increases endogenous FSH and LH se- mia. When reproductive tract lesions are the cause of thalamic thyrotropin-releasing hormone (TRH) is thought infertility, corrective surgery or in vitro fertilization is the to contribute to excess PRL secretion, as experimental stud- treatment of choice. CHAPTER 38 The Female Reproductive System 683 REVIEW QUESTIONS DIRECTIONS: Each of the numbered (E) Increased secretion of FSH (A) The oviduct and has entered the items or incomplete statements in this 5. The theca interna cells of the graafian second meiotic division section is followed by answers or by follicle are distinguished by (B) The uterus and has completed the completions of the statement. Select the (A) Their capacity to produce first meiotic division ONE lettered answer or completion that is androgens from cholesterol (C) Metaphase of mitosis BEST in each case. Estradiol synthesis in the graafian (C) Aromatization of testosterone to (E) The uterus, extruding the second follicle involves estradiol polar body and implanting (A) Activation of LH-stimulated (D) The lack of a blood supply 10. The enzyme, 5 -reductase is granulosa production of androgen (E) The production of inhibin responsible for (B) Stimulation of aromatase in the 6. Disruption of the hypothalamic- (A) Conversion of cholesterol to granulosa cell by FSH pituitary portal system will lead to pregnenolone and enhancing (C) Decreased secretion of (A) High circulating levels of PRL, low steroidogenesis progesterone from the corpus luteum, levels of LH and FSH, and ovarian (B) Conversion of testosterone to resulting in increased LH atrophy dihydrotestosterone (D) Inhibition of the LH surge during (B) Enhanced follicular development as (C) Aromatization of testosterone to the preovulatory period a result of increased circulating levels estradiol (E) Synergy between FSH and of PRL (D) Increasing the synthesis of LH progesterone (C) Ovulation, followed by increased (E) Female secondary sex 2. Granulosa cells do not produce circulating levels of progesterone characteristics estradiol from cholesterol because they (D) A reduction of ovarian inhibin do not have an active levels, followed by increased SUGGESTED READING (A) 17 -Hydroxylase circulating FSH Carr BR, Blackwell RE. Textbook of Re- (B) Aromatase (E) Excessive androgen production by productive Medicine. Textbook of En- (E) Steroidogenic acute regulatory (A) Inhibits the secretion of LH and docrine Physiology. A clinical sign indicating the onset of (B) Is produced by granulosa cells and Johnson MH, Everitt BJ. Essential Repro- the menopause is inhibits the secretion of FSH duction. Oxford: Blackwell Science, (A) The onset of menses near age 50 (C) Only has local ovarian effects and 2000.

First 160 mg kamagra super with mastercard, increases in Stroke volume heart rate reduce the duration of the action potential and, Decrease Treppe thus, the duration of systole, so the time available for dias- Increase (small effect) tolic filling decreases less than it would otherwise. Second, faster heart rates are accompanied by an increase in the Cardiac force of contraction, which tends to maintain stroke vol- output ume. The increased contractility is sometimes called treppe or the staircase phenomenon. Various effects of norepinephrine on the heart com- pensate for the decreased duration of diastole and hold stroke Effects of Increased Heart Rate as a Result of Changes in volume relatively constant, so that cardiac output increases with Autonomic Nerve Activity. The words “Increase” and “Decrease” in occurs because of decreased parasympathetic and in- small type denote quantitatively less important effects than the creased sympathetic neural activity. CHAPTER 14 The Cardiac Pump 245 3) Disease states, such as coronary artery disease, my- ocarditis (see Chapter 10), bacterial toxemia, and alter- ations in plasma electrolytes and acid-base balance 4) Intrinsic changes in contractility with changes in heart rate and/or afterload Heart rate is influenced primarily by sympathetic and parasympathetic nerves to the heart and, by a lesser extent, by circulating norepinephrine and epinephrine. The effect A of heart rate on cardiac output depends on the extent of concomitant changes ventricular filling and contractility. C Heart failure is a major problem in clinical medicine (see Clinical Focus Box 14. A V = C THE MEASUREMENT OF CARDIAC OUTPUT mg mL = The ability to measure output accurately is essential for per- mg/mL forming physiological studies involving the heart and man- FIGURE 14. Cardiac output is measured either by one of The volume (V) of liquid in the beaker equals the amount (A) of several applications of the Fick principle or by observing dye divided by the concentration (C) of the dye after it has dis- changes in the volume of the heart during the cardiac cycle. Cardiac Output Can Be Measured Using Variations of the Principle of Mass Balance A C V The use of mass balance to measure cardiac output is best Because A is known and C can be measured, V can be understood by considering the measurement of an un- calculated: known volume of liquid in a beaker (Fig. The vol- ume can be determined by dispersing a known quantity of V A/C (6) dye throughout the liquid and then measuring the con- When the principle of mass balance is applied to cardiac centration of dye in a sample of liquid.