Homeostasis and Energy Regulation in Animals

Homeostasis

Maintenance of stable internal environment in organisms.

Allostasis

Process of achieving stability through change.

Drive States

Psychological processes that sustain (nurture/support) certain behaviors.

Endothermy

Heat generated internally through metabolism.

Ectothermy

Heat derived primarily from the environment.

Thermoregulation

Regulation of body temperature for optimal function.

Set Point

Desired value for a physiological variable.

Negative Feedback

Process that counteracts deviation from set point.

Set Zone

Range of tolerance around a set point.

Redundancy in Systems

Multiple mechanisms ensure stability in homeostasis.

Pros of Endothermy

Constant body temperature, active in various environments.

Cons of Endothermy

Higher energy expenditure for heat production.

Pros of Ectothermy

Lower energy requirements, efficient in warm climates.

Cons of Ectothermy

Dependent on environmental temperatures for activity.

Compensatory Action

Response initiated when set point is deviated.

Behavioral Adaptations

Specialized actions to maintain internal stability.

Physiological Systems

Biological processes regulating homeostasis.

Internal Environment Changes

Alterations affecting physiological and psychological states.

Optimal Temperature Range

Ideal conditions for cellular function and reactions.

Negative Feedback

Process to maintain stable internal conditions.

Thermoregulatory System

Mechanism to regulate body temperature.

Receptors

Sensory cells detecting environmental changes.

Preoptic Area (POA)

Hypothalamic region controlling cold responses.

Lateral Hypothalamus

Region managing behavioral temperature regulation.

Physiological Responses

Automatic body adjustments to temperature changes.

Behavioral Responses

Conscious actions to regulate body temperature.

Body Surface Changes

Adjustments like huddling to manage heat.

External Environment Changes

Using clothing or nests for temperature control.

Movement into Sun or Shade

Behavioral adjustment for thermal comfort.

Endotherms

Warm-blooded animals regulating internal temperature.

Compartmentalization of Fluids

Separation of body fluids into distinct areas.

Diffusion

Movement of particles from high to low concentration.

Osmosis

Water movement across a semipermeable membrane.

Semipermeable Membrane

Barrier allowing selective passage of substances.

Osmotic Thirst

Thirst from cellular dehydration due to solute loss.

Hypovolemic Thirst

Thirst from loss of blood volume.

Fluid Loss Sensors

Mechanisms detecting dehydration and fluid imbalance.

Salt Homeostasis

Balance of salt levels crucial for hydration.

Physiological Responses to Thirst

Body's mechanisms to restore fluid balance.

Brain's Drinking Regulation

Central control of thirst and hydration behavior.

Thermal Regulation Importance

Essential for survival in varying environments.

Behavioral Thermoregulation

Active adjustments to maintain optimal body temperature.

Fluid regulation

Prevention of dehydration in land animals.

Intracellular compartment

Fluid contained within body cells.

Extracellular compartment

Fluid outside cells, includes interstitial fluid and plasma.

Interstitial fluid

Fluid between cells in the extracellular compartment.

Blood plasma

Liquid component of blood, part of extracellular fluid.

Water movement

Constant exchange between intracellular and extracellular compartments.

Osmosis

Passive solvent movement through a semipermeable membrane.

Osmotic pressure

Force driving water across a membrane due to solute concentration.

Physiological saline

0.9% NaCl solution for maintaining cell conditions.

Hypertonic solution

Extracellular fluid more concentrated than 0.9% NaCl.

Hypotonic solution

Extracellular fluid less concentrated than 0.9% NaCl.

Osmotic thirst

Thirst triggered by high extracellular fluid salinity.

High solute concentration

Stimulates osmotic thirst for water intake.

Low extracellular volume

Signals need for water due to fluid loss.

Obligatory water loss

Water loss through respiration and urination.

Circumventricular organs

Brain structures monitoring fluid balance.

Hypothalamus

Brain region detecting extracellular fluid concentration.

Cortical regions

Areas involved in conscious perception of thirst.

Salt importance

Essential for various physiological functions.

Solute concentration increase

Causes water to move out of cells.

Fluid balance monitoring

Regulation of body fluids by specialized brain structures.

Cellular conditions

Maintained by extracellular fluid buffering.

Thirst remedy

Actions taken to restore hydration.

Dehydration prevention

Mechanisms to avoid excessive water loss.

Semipermeable membrane

Barrier allowing selective movement of substances.

Concentration equalization

Process where solute levels become uniform.

Hypovolemic Thirst

Triggered by loss of fluid volume.

Extracellular Space

Fluid outside cells; retains salt for balance.

Pressure Sensors

Detect drop in blood vessel pressure.

Sympathetic Nervous System

Causes arterial constriction during low volume.

Thirst Response

Brain activation for fluid intake; not solely drinking.

Vasopressin

Peptide hormone increasing water absorption in kidneys.

Aldosterone

Steroid hormone conserving sodium; increases salt appetite.

Basal Metabolism

Energy expenditure at rest; crucial for dieting.

Circulating Glucose

Essential for energy; regulates bodily functions.

Insulin Secretion

Controls glucose utilization by body cells.

Fluid Volume Loss

Stimulates thirst without changing fluid concentration.

Kidneys Role

Regulate urine production and fluid balance.

Hormonal Activation

Initiates responses to maintain blood pressure.

Energy Storage Mechanisms

Processes for storing energy for future needs.

Energy Balance

Regulation of energy intake and expenditure.

Nutrients

Chemicals required for body function and growth.

Digestion

Process of breaking down food for absorption.

Homeostasis

Maintenance of stable internal body conditions.

Glucose

Principal sugar used for energy in the body.

Glycogen

Stored glucose in liver and muscles.

Insulin

Hormone regulating glucose storage and absorption.

Glucagon

Hormone converting glycogen back to glucose.

Adipose Tissue

Fat storage tissue in the body.

Metabolism

Chemical processes for energy production and use.

Caloric Intake

Total calories consumed from food and beverages.

Diabetes Mellitus

Condition from insulin failure to absorb glucose.

Type 1 Diabetes

Juvenile-onset diabetes; no insulin production.

Type 2 Diabetes

Adult-onset diabetes; reduced insulin sensitivity.

Insulin Release

Triggered by food intake and various mechanisms.

Cephalic Phase

Insulin release triggered by food sensory cues.

Gastric Phase

Insulin release when food enters the digestive tract.

Intestinal Phase

Insulin release signaled by liver glucodetectors.