Homeostasis and Feedback Loops in Physiology

These flashcards cover key concepts related to homeostasis, feedback loops, and the physiological mechanisms involved in maintaining internal stability.

What does homeostasis refer to in physiology?

The maintenance of a relatively constant internal environment in the presence of changing external conditions.

What are negative feedback loops used for?

To counteract initial changes in the body to maintain homeostasis.

What is the primary distinction of positive feedback compared to negative feedback?

Positive feedback exacerbates the initial change, moving the system further away from a set point.

How do peptide hormones and steroid hormones differ in their action?

Peptide hormones act at the cell membrane, while steroid hormones can pass through plasma membranes and act within the cell.

What major systems do animals use to coordinate and control physiological responses?

The endocrine system and the nervous system.

Why can positive feedback not contribute to homeostasis?

Because it amplifies the initial change instead of reversing it, thus moving the system further from stability.

What hormone is secreted when blood glucose levels rise after a meal?

Insulin.

What are the two components involved in the stress response?

The short term fight-or-flight response and the long term hormonal cascade.

What is the role of the hypothalamus in the stress response?

It releases CRH which signals the anterior pituitary to release ACTH, leading to cortisol release.

What kind of feedback is involved in childbirth through oxytocin release?

Positive feedback.

How does thermoregulation differ between endotherms and ectotherms?

Endotherms generate metabolic heat to maintain body temperature, while ectotherms rely on external environmental heat.

What happens during vasoconstriction in the circulatory system?

It reduces blood flow near the surface of the skin, conserving heat.

What is the physiological process of shivering?

It is a response that increases metabolic heat production to warm the body.

What changes occur in blood flow during the fight-or-flight response?

Blood flow is redirected towards muscles and vital organs while being reduced in non-essential areas.

What system releases hormones throughout the body and is well suited for gradual changes?

The endocrine system.

What is the function of glucagon in blood glucose regulation?

It stimulates the liver to break down glycogen and release glucose into the blood when glucose concentration is low.