BPK 205 Chapter Notes - Chapter 1-6: Blood Vessel, Homeostasis, Positive Feedback

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amethystworm242

14 Oct 2011

School

Simon Fraser University

Department

Biomedical Physio & Kines

Course

BPK 205

Professor

Parveen Bawa

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Document Summary

[total one page with a figure; 15 minutes] The body maintains its 37 deg c temperature by countering the loss of heat instigated by the cold water. Nerves in the skin send signals to the hypothalamus in the brain that senses the loss in body heat. This triggers the release of signals of both the endocrine and nervous systems that start heat preserving actions. These actions may include: reduced sweating, teeth chattering, shivering, blood flow distribution concentrated more at the core of the body rather than skin. This system is called a negative feedback system. There is a stimulus (the cold water), that causes a change in temperature that is sensed by a sensor (nerves). This triggers an input signal that travels to an integrating center (hypothalamus) via the afferent pathway. The integrating center triggers multiple signals that travel via the efferent pathway to different targets/effectors (blood vessels, sweat glands, muscles).

Related Questions

Why does it make sense that the sensors and controller of body temperature reside in the brain?

	A.	Because the brain enables the body's response to temperature changes
	B.	Because deep inside the brain is considered the body's core
	C.	Because temperature changes happen most quickly in the brain
	D.	Because the brain works best at the correct temperature
	E.	Because temperature changes affect the brain first

How does the hypothalamus monitor water in the body?

	A.	If blood is too concentrated, the hypothalamus nerve cells will contain too much salt.
	B.	If blood is too concentrated, the hypothalamus it registers dehydration in its own cells.
	C.	If blood is too concentrated, the hypothalamus registers ADH in the blood.
	D.	If blood is too concentrated, nerve cells in the hypothalamus it has nerve cells that lose water by osmosis and fire more slowly.
	E.	If blood is too concentrated, in the hypothalamus it registers that its cells are losing water by osmosis.

* Bill is outside on a snowy day without a warm coat. His skin is ale and chille and he begins to shiver. Explain how these responses are attempts of his body to maintain homeostasis of temperature. What other responses might raise his body temperature?

* Arrange in order the events that occur in the production of a fever of 39.4^âoC (103^âoF) and recovery from this state

A. 39.4^âoC temperature is reached and maintained.

B. Prostaglandins (PGs) cause the hypothalamic "thermostat" to be reet from normal 37.5^âoC (98.6^âoF) to a higher temperature such as 39.4^âoC (103^âoF).

C. Vasoconstriction and shivering occur as heat is conserved in order to raise body temperature to the 39.4^âoC (10^â3^âoF) level ddirected by the hypothalamus.

D. Source of pyrogens is removed (for example, bacteria are killed by antibiotics), lowering hypothalamic "thermostat" to 37.5^âoC (98.6^âoF).

E. "Crisis" occurs. Obeying hypothalamic orders, the body shifts to heat loss mechanisms such as sweating and vasodilation, returning body temperature to normal.

F. Infectious organisms cause phagocytes to release interleukin-1, which then causes hypothalamic release of PGs.

Arrange in order the events that occur in the production of a fever of 39.4 C (103 F) and recovery from this state

A.39.4 C the temperature is reached and maintained

B.Prostaglandins (PGs) cause the hypothlmic thermostat to be reset from normal 37.5 C (98.6 F) to a higher temperature such as 39.4 C (103 F)

C.Vasocostriction and shivering occur as heat is conserved in order to raise body temperature to the 39.4 C (103 F) level directed by hypothalamus

D.Sourse of pyrogens is removed ( for example bacteria are killed by antibiotics )lowering phytoalamic thermostat to 37.5 C (98.6 F)

E.Crisis occurs .Obeying hypothalamic orders the body shifts to heat loss mechanism such as sweating and vasodilation returning body temperature to normal.

F.Infectious organism cause phagocytes to release interleukin-1 which the causes hypothalamic release of PGs.

BPK 205 Chapter Notes - Chapter 1-6: Blood Vessel, Homeostasis, Positive Feedback

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