CH 40 Basic Principles of Animal Form and Function

Bio 1270 Molloy Univeristy

_______ is proportional to a cell’s surface area, while amount of material that must be exchanged is proportional to ______.

Rate of exchange with environment; Volume of cell.

What evolutionary adaptations that enable more complex organisms to exchange with the environment?

Specialized structures, like lungs or gills, and increased surface area through invaginations or extensive branching or folded structures which allow for efficient gas excahnge and nutrient exchange.

What is the hierarchical organization of body plans?

Cells —> Tissues —> Organs —> Organ Systems

Name the four main types of animal tissues

Epithelial Tissues, Connective, Muscle, Nervous

Epithelial Tissues:

• Covers the outside of the body

• lines the organs and cavities within the body

• contain closely packed cells

  • Shape of the Epithelial Cells

    • Cuboidal (dice like)

      • Simple Cuboidal Epithelium: A single layer of cells specialized for secretion and absorption, commonly found in kidney tubules, thyroid follicles, and gland ducts.

      • Stratified Cuboidal Epithelium: Multiple layers of cube-shaped cells designed for protection, found in the excretory ducts of salivary and sweat glands

    • Columnar (like bricks on end)

      • Simple Columnar: A single layer of tall cells specialized for absorption/secretion (e.g., stomach, intestines).

      • Pseudostratified Columnar: Appears stratified because nuclei are at different levels, but it is actually a single layer where all cells touch the basement membrane (e.g., trachea).

      • Stratified Columnar: Multiple layers with apical columnar cells, found in the male urethra and conjunctiva

    • Squamous (floor tiles)

      • Simple Squamous Epithelium: A single layer of flat, thin cells, ideal for diffusion, osmosis, and filtration. Examples: Lung alveoli, capillaries, kidney glomeruli.

      • Stratified Squamous Epithelium: Multiple layers of cells, with flat, squamous cells on the surface and cuboidal/columnar cells at the basal layer.

        • Keratinized: Found on skin (epidermis); contains protective keratin and is waterproof.

        • Non-keratinized: Found in moist areas like the mouth, throat, and esophagus

Connective Tissue

• holds many tissues and organs together and in place

• contains sparsely packed cells scattered through an extracellular matrix

• matrix consists of fibers in a liquid, jellylike, or solid foundation

  • Connective Tissue Proper

    • Loose (Areolar, Adipose, Reticular)

      • Pads organs, stores fat for fuel, and provides immune defense

    • Dense (Regular, Irregular, Elastic)

      • Form tendons and ligaments; provide high tensile strength

  • Supportive Connective Tissue

    • Cartilage (Hyaline, Fibro, Elastic)

      • Cushions joints and provides flexible structural support

        • Nose & Ears

    • Bone (Osseous)

      • Forms the skeleton; protects internal organs and stores minerals

  • Fluid Connective Tissue

    • Blood & Lymph

      • Transports nutrients, gases, and waster; supports immune function

Muscle Tissue

• Muscle tissue is responsible for nearly all types of body movement

• Muscle cells consist of filaments of the proteins actin and myosin, which together enable muscles to contract

  • Skeletal Muscle: Striated, long, cylindrical, multi-nucleated fibers attached to bones via tendons. They operate under voluntary control for movement and posture.

  • Cardiac Muscle: Striated, branched, and uninucleated cells connected by intercalated discs. Located only in the heart, these contract involuntarily to pump blood.

  • Smooth Muscle: Non-striated, spindle-shaped, and involuntary cells found in the walls of internal organs (e.g., stomach, intestines, blood vessels) to move substances.

Nervous Tissue

• Functions in the receipt, processing, and transmission of information

• Nerous tissue contains

  • Nervous tissue contains

    • Neurons, nerves cells, which transmit nerve impulses

    • Glial cells, or glia, which support cells

• Found in brain, spinal cord, and peripheral nerves

Where epithelial tissue can be found in an animal?

• Covers the outside of the body and lines the organs and cavities within the body; closely packed

Name the three shapes of epithelial cells

• Cuboidal (like dice) (flat)

• Columnar (like brick on end) (Cube-Like)

• Squamous (like Floor Tiles)(Tall)

Name the two major proteins in muscle filaments

• Muscles cells consist of filaments of the proteins actin and myosin, which together enable muscles to contract

List the functions of Nervous Tissue

• Senses stimuli, processes information, transmits signals

Name the two types of cells in the nervous tissue and define their functions, respectively

1. Neurons, or nerve cells, which transmit nerve impulses, transmit signals

2. Glial cells, or glia, which support cells, nourish, and protect neurons

Name the two major systems for coordinating and controlling responses to stimuli in animals and define their functions, respectively.

• The endocrine system releases signaling molecules that are carried to all locations in the body, signaling via hormones, slower but long-lasting

• The nervous system transmits information along dedicated routes, connecting specific location in the body, rapid signaling via neurons, fast responses

Compare the endocrine system with nervous systems: signaling molecules. duration/speed, targets and suited responses

Signaling Molecules

• Endocrine

  • Hormones

• Nervous

  • Neurotransmitters

Speed/Duration

• Endocrine

  • Slow, Long-lasting (minutes, hours)

• Nervous

  • Fast, Short-lived (seconds)

Targets

• Endocrine

  • Distant Cells, All location in the body

• Nervous

  • Specific Cells, dedicated routes, connecting specific locations in body

Suited Responses

• Endocrine

  • Growth, Metabolism, coordinating gradual changes that affect the entire body

• Nervous

  • Immediate Responses

Then endocrine and nervous system often work in close coordination; both help maintain in a stable internal environment

Define Regular and Conformer

Regulator:

• Uses internal control mechanisms to control internal change in the face of external fluctuation.

• Regulators use energy to maintain homeostasis

  • Ex:

    • Maintain body temperature around 37ºC even if it’s cold or hot —> Humans

Conformers:

• allows its internal condition to vary with certain external changes

Ex:

• Ectothermic reptiles —> body temperature changes with environmental temperature.

Conformers use less energy, but they tolerate environmental changes.

Define negative feedback and positive feedback

Negative Feedback

• is a control mechanism that “damps” a stimulus

  • plays a major role in homeostasis in animals

  • homeostasis moderates but doesn’t eliminate changes in the internal environment

Positive Feedback

• amplifies a stimulus and does not play a major role in homeostasis

  • it helps drive a process to completion

    • Ex: childbirth a mothers uterus contracts more in order to push the baby out

Define Circadian Rhythm

• Set points and normal ranges can change with age and show cyclic variation (changes that happen repeatedly in a regular pattern over time).

• In animals and plants, a circadian rhythm governs physiological changes that occur roughly every 24 hours.

Define Acclimation

• another word for homeostasis

• Change in an animal’s physiology as it adjusts to changes in its external environment

  • Ex: is adaption to changes in altitude

Define Thermoregulation

• is the process by which animals maintain an internal temperature within a normal range

Specify endothermic animals and ectothermic animals

• Endothermic- animals generate heat by metabolism; birds and mammals are endotherms

• Ectothermic- animals gain heat from external sources; ectotherms include fishes, amphibians, nonavian reptiles, and most invertebrates.

• Endotherms can maintain a stable body temperature even in the face of large fluctuations in environmental temperature.

• Endothermy is more energetically expensive than ectothermy; ectotherms need to consume less food than equally sized endotherms

• In general, ectotherms tolerate greater variation in internal temperature

Name the four physical processes that organisms exchange heat

• Radiation

  • Heat is transferred as infrared energy without direct contact

  • Ex: An animal gaining heat from sunlight

• Evaporation

  • Heat is lost when liquid (like sweat) turns into vapor

  • Ex: Sweating cools the body

• Convection

  • Heat is transferred through the movement of air or water

  • Ex: Wind carrying heat away from the body

• Conduction

  • Heat is transferred by direct contact between objects

  • Ex: An animal losing heat when ling on cold ground

List the components in the integumentary system

• Skins

• Hair

• Nails

• Sweat glands

• Sebaceous glands (oil)

List the five adaptations help animals thermoregulate

• Insulation

  • Fur, feathers, or fat that reduces heat loss.

• Circulatory adaptations

  • Changes in blood flow (like vasodilation and vasoconstriction) to control heat loss or retention.

• Evaporative cooling

  • Cooling by evaporation, such as sweating or panting.

• Behavioral thermoregulation

  • Behavioral responses like moving into shade, basking in the sun, or burrowing.

• Metabolic heat production

  • Adjusting metabolic heat production, such as shivering to generate heat.

List the body parts that serve for insulation purposes

1. Skin

2. Feathers

3. Fur

4. Blubber

• Insulation is a major thermoregulatory adaption in mammals and birds

• It reduces the flow of heat between an animal’s body and its environment

• Insulation is especially important in marine mammals such as whale and walruses

Specify countercurrent exchange

• Is a thermoregularion mechanism where heat is transferred between fluids (usually blood) flowing in opposite directions to reduce heat loss and conserve body heat.

Key points:

• Blood vessels are arranged so that warm blood leaving the body core flows next to cooler blood returning from the extremities.

• Heat moves from the warm blood to the cooler blood, warming the blood going back to the core.

• This helps maintain body temperature while minimizing heat loss to the environment.

Ex:

• Found in marine mammals, birds, sharks, fishes, and some insects.

• It helps animals keep vital organs warm, especially in cold environments.

Related thermoregulation processes:

• Vasodilation: Blood vessels widen → more blood flows to the skin → heat loss increases.

• Vasoconstriction: Blood vessels narrow → less blood flows to the skin → heat loss decreases.

What are the cooling mechanisms in mammals?

• Evaporative cooling – When the environmental temperature is higher than body temperature, evaporation helps prevent the body from overheating.

• Sweating or bathing – Moisture on the skin evaporates and removes heat from the body, helping cool the animal.

• Panting – Rapid breathing increases evaporation from the respiratory surfaces (mouth and lungs), which helps cool the body.

• Vasodilation – Blood vessels near the skin widen, increasing blood flow to the surface so more heat can be lost to the environment.

Name the thermoregulation center in mammals and list its functions

Thermoregulation center in mammals:

• Hypothalamus

Functions of the hypothalamus in thermoregulation:

1. Acts as the body’s thermostat by sensing changes in body temperature.

2. Receives signals from temperature sensors in the body and skin.

3. Triggers heat-loss mechanisms when the body is too warm (for example sweating and vasodilation).

4. Triggers heat-producing mechanisms when the body is too cold (such as shivering and vasoconstriction).

5. Regulates fever during infections by raising the normal temperature set point.

6. Coordinates responses that help maintain a stable internal body temperature (homeostasis).

Specify Bioenergics

• the overall flow and transformation of energy in an animal

• determines an animal’s nutritional needs, and it relates to an animal’s size, activity, and environment

Specify Metabolic Rate

• the sum of all the energy an animal uses in a unit of time

Can be determined by:

• animal’s heat loss

• the amount of oxygen consumed or carbon dioxide produced

• Measuring energy content of food consumed and energy lost in waste products

Define Basal Metabolic rate and Standard metabolic rate

• Basal Metabolic Rate (BMR): The metabolic rate of an endotherm at rest, with an empty stomach, not under stress, and measured within a comfortable temperature range.

• Standard Metabolic Rate (SMR): The metabolic rate of a fasting, non-stressed ectotherm at rest measured at a specific temperature.

• Key point: Ectotherms generally have much lower metabolic rates than endotherms of similar size.

List the factors that influence metabolic rate

1. Age

2. Sex (gender)

3. Body size (mass)

4. Activity level

5. Temperature

6. Nutrition

Additional points:

• Metabolic rate is roughly proportional to body mass³⁄⁴ (m³⁄⁴).

• Smaller animals have higher metabolic rates per gram than larger animals.

• Because of this, smaller animals also have:

  • Higher oxygen delivery rates

  • Faster breathing rates

  • Faster heart rates

  • Greater relative blood volume

Define torpor, hibernation and estivation

• Torpor: A physiological state of reduced activity and metabolism that helps animals conserve energy during unfavorable conditions. Many small mammals and birds show daily torpor.

• Hibernation: A long-term form of torpor used to survive winter cold and food shortages. During hibernation, metabolic rates can be about 20 times lower than normal.

• Estivation: Also called summer torpor, it allows animals to survive high temperatures and lack of water during hot seasons.