Wk 7 Biomedical Science PT 1

What are the four basic methods of cell-to-cell communication?

1. Direct cell-to-cell contact 2. Local signaling (paracrine) 3. Long-distance signaling (endocrine) 4. Neuronal signaling.

What is the general pattern of a signal pathway?

A signal pathway generally consists of a signaling molecule binding to a receptor, leading to a cascade of cellular responses.

How do signaling molecules interact with target-cell receptors?

Signaling molecules bind to specific receptors on target cells, triggering a conformational change that initiates a response.

What is the difference between chemical and electrical signals?

Chemical signals involve the release of hormones or neurotransmitters, while electrical signals are changes in membrane potential that propagate along neurons.

What are the differences between endocrine and neural control?

Endocrine control involves hormones that act over long distances and take longer to exert effects, while neural control involves rapid transmission of signals via neurons.

What are the two chemical classes of hormones based on their solubility?

1. Lipid-soluble hormones (steroids) 2. Water-soluble hormones (peptides and amines).

What are the two general mechanisms of hormone action?

1. Direct gene activation (lipid-soluble hormones) 2. Second messenger systems (water-soluble hormones).

What is the relationship between the hypothalamus and the pituitary gland?

The hypothalamus regulates the pituitary gland, which releases hormones that control various endocrine functions.

What is the mechanism of control of hormone secretion?

Hormone secretion is regulated by feedback mechanisms, neuroendocrine signals, and changes in blood levels of ions or nutrients.

What are the hormones and functions of the anterior pituitary?

Hormones include GH (growth hormone), TSH (thyroid-stimulating hormone), ACTH (adrenocorticotropic hormone), LH, and FSH (luteinizing and follicle-stimulating hormones). Functions include growth and metabolism regulation.

What are the primary components of a signal pathway?

The primary components include a signaling molecule, a receptor on the target cell, signal transduction mechanisms, and a cellular response.

What role do receptors play in cell signaling?

Receptors bind specific signaling molecules and initiate a response in the target cell through conformational changes.

What type of signaling involves direct communication between adjacent cells?

Juxtacrine signaling involves direct contact or communication between adjacent cells.

What is paracrine signaling?

Paracrine signaling is the process where signaling molecules released by one cell act on nearby target cells.

Describe the importance of feedback loops in hormonal regulation.

Feedback loops, such as negative feedback, help maintain homeostasis by regulating hormone levels and physiological responses.

What is the function of exocrine glands?

Exocrine glands secrete substances (e.g., enzymes, sweat) into ducts that lead to external environments or body cavities.

What is a second messenger in hormone action?

A second messenger is an intracellular molecule that transmits signals from a receptor to target molecules inside the cell, amplifying the signal.

How does the hypothalamus control the pituitary gland?

The hypothalamus produces releasing and inhibiting hormones that regulate the secretion of hormones from the anterior pituitary.

What hormones are typically associated with the adrenal cortex?

Hormones from the adrenal cortex include cortisol, aldosterone, and androgens.

What is the concept of homeostasis in communication and integration?

Homeostasis refers to the process by which organisms maintain a stable internal environment through communication and integration among various systems

What is the function of signaling molecules in cell communication?

Signaling molecules transmit information between cells, triggering specific actions or responses in target cells.

What is the key difference between endocrine and neural signaling?

Endocrine signaling involves hormones traveling through the bloodstream to distant targets, whereas neural signaling occurs via electrical impulses directly to target cells.

What are the types of signaling based on distance?

There are three types of signaling: autocrine (signals affecting the same cell), paracrine (signals affecting nearby cells), and endocrine (signals affecting distant cells).

What is the primary action of lipid-soluble hormones?

Lipid-soluble hormones typically pass through the cell membrane and act directly on nuclear receptors to influence gene expression.

What is the role of water-soluble hormones?

Water-soluble hormones bind to receptors on the cell surface and activate second messenger systems to exert their effects.

How are hormones secreted from endocrine glands?

Hormones are secreted through exocytosis in response to specific stimuli, such as changes in ion concentration or other hormones.

What is the physiological relevance of the negative feedback mechanism in hormonal control?

Negative feedback helps to stabilize physiological systems by reducing the output or activity when a set point is reached.

Where is the anterior pituitary located, and what is its primary function?

The anterior pituitary is located below the hypothalamus and primarily functions to secrete hormones that regulate other endocrine glands.

What are the effects of stress on hormone levels?

Stress triggers the release of cortisol and adrenaline, leading to increased heart rate, blood pressure, and energy availability.

How does the body integrate information for homeostasis?

The body integrates information through neural and hormonal signals to coordinate responses and maintain stable internal conditions