1. Activation of Vit. D involves Kidney and Liver and liver is part of Digestive system. Answer is Digestive system 2. Calcium homeostasis and phosphate homeostasis are intimately tied to each other for two reasons. First, calcium and phosphate are the principal components of hydroxyapatite crystals [Ca10(PO4)6(OH)2)], which by far constitute the major portion of the mineral phase of bone. Second, they are regulated by the same hormones, primarily parathyroid hormone (PTH) and 1,25-dihydroxyvitamin D (calcitriol) and, to a lesser extent, the hormone calcitonin. These hormones act on three organ systems-the bone, the kidneys, and the gastrointestinal (GI) tract-to control the levels of these two ions in plasma. Answer is Endocrine system 3. Answer is Muscular system 4. Nonspecific defenses include mechanical barriers such as skin, saliva, the lacrimal apparatus, and mucous membranes, as well as the outward flow of urine, vaginal secretions, and blood (from wounds). Phagocytosis, fever, inflammation, and molecular strategies. Answer is Integumentary System 5. Answer is the Circulatory system, Renal artery perfusion pressure directly regulates sodium excretion-a process known as pressure natriuresis-and influences the activity of various vasoactive systems such as the renin-angiotensin-aldosterone system. 6. Erythropoietin is a glycoprotein hormone produced in the kidney that acts on erythroid progenitor cells in the bone marrow. Answer is Skeleton system 7. When the animal is in a situation of crisis or stress blood flow to the kidneys is reduced for the sake of other organs such as the brain, heart and skeletal muscles. The sympathetic nervous system and a heightened level of adrenalin in the plasma cause the contraction of both the afferant and efferant arterioles. Answer is Nervous System Solution 1. Activation of Vit. D involves Kidney and Liver and liver is part of Digestive system. Answer is Digestive system 2. Calcium homeostasis and phosphate homeostasis are intimately tied to each other for two reasons. First, calcium and phosphate are the principal components of hydroxyapatite crystals [Ca10(PO4)6(OH)2)], which by far constitute the major portion of the mineral phase of bone. Second, they are regulated by the same hormones, primarily parathyroid hormone (PTH) and 1,25-dihydroxyvitamin D (calcitriol) and, to a lesser extent, the hormone calcitonin. These hormones act on three organ systems-the bone, the kidneys, and the gastrointestinal (GI) tract-to control the levels of these two ions in plasma. Answer is Endocrine system 3. Answer is Muscular system 4. Nonspecific defenses include mechanical barriers such as skin, saliva, the lacrimal apparatus, and mucous membranes, as well as the outward flow of urine, vaginal secretions, and blood (from wounds). Phagocytosis, fever, inflammation, and molecular strategies. Answer is Integumentary System 5. Answer is the Circulatory system, Renal artery perfusion pressure directly regulates sodium .

1. 1. Activation of Vit. D involves Kidney and Liver and liver is part of Digestive system. Answer
is Digestive system
2. Calcium homeostasis and phosphate homeostasis are intimately tied to each other for two
reasons. First, calcium and phosphate are the principal components of hydroxyapatite crystals
[Ca10(PO4)6(OH)2)], which by far constitute the major portion of the mineral phase of bone.
Second, they are regulated by the same hormones, primarily parathyroid hormone (PTH) and
1,25-dihydroxyvitamin D (calcitriol) and, to a lesser extent, the hormone calcitonin. These
hormones act on three organ systems-the bone, the kidneys, and the gastrointestinal (GI) tract-to
control the levels of these two ions in plasma. Answer is Endocrine system
3. Answer is Muscular system
4. Nonspecific defenses include mechanical barriers such as skin, saliva, the lacrimal apparatus,
and mucous membranes, as well as the outward flow of urine, vaginal secretions, and blood
(from wounds). Phagocytosis, fever, inflammation, and molecular strategies. Answer is
Integumentary System
5. Answer is the Circulatory system, Renal artery perfusion pressure directly regulates sodium
excretion-a process known as pressure natriuresis-and influences the activity of various
vasoactive systems such as the renin-angiotensin-aldosterone system.
6. Erythropoietin is a glycoprotein hormone produced in the kidney that acts on erythroid
progenitor cells in the bone marrow. Answer is Skeleton system
7. When the animal is in a situation of crisis or stress blood flow to the kidneys is reduced for the
sake of other organs such as the brain, heart and skeletal muscles. The sympathetic nervous
system and a heightened level of adrenalin in the plasma cause the contraction of both the
afferant and efferant arterioles. Answer is Nervous System
Solution
1. Activation of Vit. D involves Kidney and Liver and liver is part of Digestive system. Answer
is Digestive system
2. Calcium homeostasis and phosphate homeostasis are intimately tied to each other for two
reasons. First, calcium and phosphate are the principal components of hydroxyapatite crystals
[Ca10(PO4)6(OH)2)], which by far constitute the major portion of the mineral phase of bone.
Second, they are regulated by the same hormones, primarily parathyroid hormone (PTH) and
1,25-dihydroxyvitamin D (calcitriol) and, to a lesser extent, the hormone calcitonin. These
hormones act on three organ systems-the bone, the kidneys, and the gastrointestinal (GI) tract-to
control the levels of these two ions in plasma. Answer is Endocrine system

2. 3. Answer is Muscular system
4. Nonspecific defenses include mechanical barriers such as skin, saliva, the lacrimal apparatus,
and mucous membranes, as well as the outward flow of urine, vaginal secretions, and blood
(from wounds). Phagocytosis, fever, inflammation, and molecular strategies. Answer is
Integumentary System
5. Answer is the Circulatory system, Renal artery perfusion pressure directly regulates sodium
excretion-a process known as pressure natriuresis-and influences the activity of various
vasoactive systems such as the renin-angiotensin-aldosterone system.
6. Erythropoietin is a glycoprotein hormone produced in the kidney that acts on erythroid
progenitor cells in the bone marrow. Answer is Skeleton system
7. When the animal is in a situation of crisis or stress blood flow to the kidneys is reduced for the
sake of other organs such as the brain, heart and skeletal muscles. The sympathetic nervous
system and a heightened level of adrenalin in the plasma cause the contraction of both the
afferant and efferant arterioles. Answer is Nervous System