During childbirth, as a baby's head is pressed against the mother's cervix, signals are relayed via nerves from cervix to the mother's brain. The brain initiates the secretion of oxytocin (a hormone) from the mother's pituitary gland. Oxytocin stimulates further uterine contractions. As the uterus contracts even harder in response to oxytocin, the baby's head is pushed harder against the cervix; this stimulates yet more nerve signals to the mother's brain, resulting in yet more oxytocin secretion until finally the baby is pushed through the cervix. This process of childbirth is an example of
A. positive feedback.
B. acclimatization.
C. feedforward regulation.
D. negative feedback.
E. adaptation.
Answer: A
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The breast bone is called the?
a. scapula b. sternum c. manubrium d. xiphoid process.
Some damaged skin structures are replaced by a fibrous, noncellular ________ tissue.
Fill in the blank(s) with the appropriate word(s).
Which of the following is associated with osteoclast reabsorption of bone?
A. Calcium ions are actively transported from blood to bone matrix. B. The protein components of bone matrix are synthesized. C. Osteoblasts form collagen and proteoglycans. D. Blood calcium is decreased. E. Hydrogen ions form an acid environment in bone matrix.
A cancerous tumor found in bone would be considered what type of tumor?
A. Sarcoma B. Leukemia C. Lymphoma D. Carcinoma