Answer: B. pressure changes in the thorax
Explanation:
The veins are the blood vessels which returns the deoxygenated blood from all the tissues and cells of the body back to the heart. The ventricular systole, venous valves, activity of the skeletal muscles and neural control over venoconstriction all influence the movement of the blood in the venous.
The pressure changes in the thorax occurs due to inspiration and expiration. During the process of inspiration, the diaphragm below the lungs contracts and moves downward while the muscles of the ribs pulls downward. When the size of the thoracic cavity increase the air pressure inside the cavity decreases and vice-versa. The pressure inside the thoracic cavity is not related with the movement of the venous blood as it regulates the exchange of the gases not the blood.
Answer:
3) 0.75m/s
Explanation:
The wavelength of a wave is calculated using the formula;
λ = v/f
Where!
λ = wavelength of wave (m)
v = velocity or speed (m/s)
f = frequency of wave (Hz)
According to this question, one end of a rope is vibrated to produce a wave with a wavelength (λ) of 0.25 m and frequency (f) of 3.0 Hz.
Using λ = v/f
v = λ × f
v = 0.25 × 3
v = 0.75m/s.
Answer:
Testes and ovaries produce two types of hormones:
androgens (male sex hormones)
estrogens (female full hormones)
In each type of gland, both types of hormones are secreted only in different amounts: the ovaries secrete more estrogen than the androgen hormones, and the sperm inversely.
Explanation:
In testicular tissue, Leydig cells produce androgen hormones: androsterone and testosterone. The ovaries produce a group of estrogen hormones and progesterone. These hormones exert their effect at puberty when the glands are activated. At puberty, the pituitary gonadostimulins activate the sex glands, whose activity leads to the development of secondary sex characteristics (the appearance of first menstruation in girls, beards and mustaches in boys, etc.).
- Provide the family with lead education
- Consider treating the child with appropriate chelation therapy
- Refer the child to a clinical center specializing in lead poisoning
If the blood lead level<span> of a preschooler is found to be between 20 and 44 mcg/dL, the nurse should provide lead education to the family. The nurse should also consider treating the child with appropriate chelation therapy. The nurse may refer the child to a clinical center specializing in lead poisoning. The nurse should refer the child to social services if the child’s blood lead level is between 15 and 19 mcg/dL. The nurse should immediately provide diagnostic testing and initiate chelation therapy if the child’s blood lead level is 70 mcg/dL or greater.</span>
