Lecture 1: Principles of Animal Physiology

A paramecium is an example of a ____.

Single-celled eukaryote

What three things must a paramecium do for itself?

Feeding, locomotion, reproduction

How does a paramecium interact with its environment?

Directly (takes in food, oxygen, ions, and releases wastes)

How do environmental changes affect a paramecium?

They directly impact it (e.g., low oxygen, bad temperature)

How many cells make up a mammal like a lion?

More than 30 trillion

Why can mammalian cells specialize in different functions?

Because they are organized into tissues and organ systems

Are most mammalian cells directly exposed to the external environment?

No, they are buffered by a controlled internal environment

The two main categories of animal cells are ____ and ____.

Germ cells and Somatic cells

What do germ cells make?

Sperm or eggs

Which cells undergo meiosis?

Germ cells

Somatic cells include all cells except ____.

Germ cells

Give an example of epithelial tissue.

Digestive tract lining

What is the main role of epithelial tissue?

Form sheets and tubes that line organs

Which type of muscle tissue is voluntary?

Skeletal muscle

Which muscle type controls involuntary movements like digestion?

Smooth muscle

Which type of muscle makes up the heart?

Cardiac muscle

Adipose tissue functions to ____.

Store fat

What are the two main roles of blood cells?

Transport and immune defense

What do bone and cartilage provide to the body?

Strength and structural support for movement

What is the primary function of neurons?

Sensing environmental changes and coordinating responses

The immediate environment of mammalian cells is the ____.

Interstitial Fluid

Cells obtain oxygen, nutrients, and ions from the ____.

Interstitial fluid

Cells dump CO2 and nitrogenous wastes into the ____.

interstitial fluid

What structures allow rapid mixing between plasma and interstitial fluid?

Capillaries

Why must interstitial fluid remain constant?

To keep cells healthy and functioning properly

Define homeostasis.

State of steady internal, physical, and chemical conditions maintained by living systems

Give three variables that homeostasis regulates.

Temperature, pH, osmolarity (many others possible)

Which nutrient molecules are most important for ATP generation?

Glucose and fatty acids

List four ions important in interstitial fluid.

Na+, K+, Cl-, Ca2+

Name two types of waste that must be removed from interstitial fluid.

CO2 and nitrogenous waste

Which systems maintain oxygen balance?

Respiratory, circulatory, skeletal muscles

Which systems regulate body temperature?

Circulatory, skin (sweating), skeletal muscles (shivering)

Which systems maintain pH?

Respiratory, excretory, circulatory

Which systems control osmolarity?

digestive, excretory, circulatory

Which systems manage nutrition?

Digestive, adipose/liver, circulatory

Which systems regulate ion composition?

Digestive, excretory, circulatory

Which systems regulate micronutrients?

Digestive and circulatory

Which systems remove nitrogenous waste?

Excretory

Which systems remove CO2?

Respiratory and circulatory

What are the three basic components of a homeostatic regulatory system?

Sensor, response, set point

What does a sensor do?

Measures a component (e.g., temperature, glucose)

What does a response do?

Acts to correct a change

What is a set point?

The optimal range where a variable should be maintained

What happens if a component is not at its set point?

An organ system is activated

What kind of feedback shuts down the response once the set point is reached?

Negative feedback

Give the normal blood glucose set point range.

70-120 mg/dL

Give the normal body temperature set point range.

36-38 °C

What is the primary mechanism for maintaining homeostasis?

Negative feedback

What household example was used to explain negative feedback?

A thermostat controlling a furnace

In the thermostat analogy, what is the sensor?

The thermometer

In the thermostat analogy, what is the control center?

The thermostat

In the thermostat analogy, what is the response?

The furnace producing heat

In the thermostat analogy, what is the set point?

The desired temperature entered into the thermostat

What are the two primary signaling mechanisms in animals?

Endocrine and nervous systems

How do hormones travel in the body?

Through the circulatory system

Do all cells respond to endocrine hormones?

No, only those with the correct receptors

Why can a small number of endocrine cells control many other cells?

Because hormones travel through blood and affect many targets

Is endocrine signaling fast or slow?

Slow

Is endocrine signaling long-lasting or short-lived?

Long-lasting

What type of changes are best regulated by endocrine signaling?

Long-term or sustained changes

How does nervous signaling occur?

Direct contact between neurons and target cells

Is nervous signaling fast or slow?

Fast

Does nervous signaling reach many or few target cells?

Few

What is the main difference in speed between nervous and endocrine signaling?

Nervous is faster, endocrine is slower

What is the main difference in duration between nervous and endocrine signaling?

Endocrine is longer lasting, nervous is shorter lasting

What must be balanced to maintain constant core body temperature?

Heat loss and heat gain

What is an ectotherm?

An animal that gains heat from the environment

What is a poikilotherm?

An animal with variable body temperature

What is an endotherm?

An animal that generates heat through metabolism

What is a homeotherm?

An animal with relatively stable body temperature

Which group has greater temperature variation: ectotherms or endotherms?

Ectotherms

Which group uses metabolism to generate heat: ectotherms or endotherms?

Endotherms

What is basal metabolism?

Continuous metabolic heat generation

List two mechanisms of heat generation besides basal metabolism.

Shivering and non-shivering thermogenesis

What part of the brain regulates core body temperature?

Hypothalamus

Which signaling system mainly controls rapid responses to temperature?

Nervous system

What muscles control shivering?

Skeletal muscles

What muscles control blood vessel dilation and sweat glands?

smooth muscles

Which signaling system regulates long-term thermogenesis?

Endocrine system

What is the primary thermogenic hormone?

Thyroid hormone