Intro to Animal Physiology Flashcards
pp 920 - pp 940
What is the relationship between organisms and their external environments?
Organisms are SHAPED by their external environments.
They must cope with the challenges posed by their immediately surrounding environments.
What is adaptation?
Beneficial adjustments, recorded as genetic changes, in populations, across generations.
What two types of stresses do organisms face?
Those that are short-term, and others that are long-term.
The external environment is constant and favourable. Is the organism in A+ shape?
Nope! The organism must maintain the optimal INTERNAL environment, by coordinating and balancing numerous systems.
What is the relationship between form and function?
The FORM (size & shape) of an organism influences they way in which they interact with their environment (FUNCTION)
Physiological functions are tightly integrated and permit organisms to cope with environmental challenges.
Why is exchange so crucial to organisms and their individual cells?
Nutrients, waste products, and gases must move in and out of the cell. Typically, this is across a cell membrane.
_________ govern the strength/rate of diffusion, movement, and heat exchange
Physical laws
Why is it more challenging for bigger organisms to fulfill their basic exchange processes?
In multicellular animals, these processes often require specialized structures.
What is the relationship between the internal and external environment?
The internal environment accommodates and tolerates the challenges posed by the external environment, by the means of multiple processes and tightly integrated systems.
What is the hierarchical structure organization of an animal?
- Organism;
- Organ systems: Groups of organs that work together, providing further organization and coordination.
- Organs: Functional units containing different types of tissues.
- Tissues: Groups of cells with a similar appearance and a common functions.
- Cells
Why do we have different types of tissues?
They have different structures, suited to their functions
What are the four main categories of tissues?
Epithelial;
Connective;
Muscle;
Nervous
Epithelial tissue: Definition
Tissue that covers the outside of the body, while lining organs and cavities within the body.
Epithelial tissue: Structure and sub-types
Often sheet-like, comprised of closely-packed, connected cells. They often have tight junctions.
There are three main types (shapes):
- Cuboidal (like dice): Specialized for secretion.
- Found in the kidney and many glands - Columnar (like bricks on end): Where secretion or active absorption is important.
- Found in the intestine - Squamous (like floor tiles): Exchanges material by diffusion
- Found in the lungs
Epithelial tissue: Function
These form ‘seamless barriers’ with the surrounding internal/external environment. Shields the inside from the outside.
Barrier against mechanical injury, pathogens, fluid loss.
Form active interfaces with the environment.
What are the six main types of connective tissue?
- LOOSE
Binds epithelia to underlying tissues and holds organs in place. Found in the skin, throughout the body. - FIBROUS
Found in tendons (attach muscles to bones), and ligaments (connects bones at joints)
Firm structure - collagenous fibres. - BONE
Mineralized, forming the skeleton - CARTILAGE
- Strong, flexible support material
- Can act as cushions between vertebrae - ADIPOSE
- Stores fat for insulation and fuel - BLOOD
- Composed of blood cells and cell fragments in blood plasma
CONNECT physical, solid, and liquid structures.
What are the three main types of muscle tissue in vertebrates?
- Skeletal muscle (striated)
Voluntary movement
Optimized for directional contraction (movement of limbs) = Pushing and pulling = Force
Muscle lengthens and relaxes (horizontal)
Fibres, giving a striped appearance - Smooth muscle
Involuntary movement
Optimized for squeezing (digestive track)
Muscle compresses and relaxes - Cardiac muscle
Contraction of the heart, which is a nonstop job!
Loaded with mitochondria, so they don’t fatigue
What types of cells does nervous tissue contain?
- Neurons (nerve cells): Transmit nerve impulses
- Glial cells (glia): Nourish, insulate, replenish neurons
These two types are tightly integrated.
Which type of tissue is to the outermost part, etc.?
Epithelial;
Nervous;
Connective;
Muscle;
What are the sub-components of neurons?
- Dendrites: Root-like, “sensory”, receives signals
- Cell body
- Axon: Carries nerve impulses and signals
What is a basic requirement, for all living organisms?
Energy!
What is the energy used for?
Energy allows…
New biochemical processes to synthesize!
It also powers cell functions!
What is the primary currency for storing and releasing energy in organisms?
ATP. Some of the chemical energy is used to do WORK; the other part used to SYNTHESIZE organic molecules.
What happens to a considerable amount of energy from the food we consume?
It is lost in organic waste, or as heat
What is metabolism?
The chemical processes surrounding the conversion and the consumption of energy, and the synthesis of organic material within a living organism.
How do different animals vary in relation to energy?
They allocate energy in different ways;
They vary in their total energy use;
They vary in their rate of energy consumption for different functions (ie. Growth vs Maintenance)
The fraction of an animal’s energy budget devoted to activity depends on…
- Environment;
- Behaviour
- Size
- Thermoregulators or not
What two benchmarks can be used for metabolic rates?
BASIC METABOLIC RATE (BMR): The metabolic rate of an ENDOTHERM at rest, at a “comfortable” temperature.
aka regulators!
Minimum metabolic rate of a nongrowing, unstressed endotherm at rest, with an empty digestive tract.
STANDARD METABOLIC RATE (SMR): Metabolic rate of an ECTOTHERM at rest, at a specific temperature.
aka conformers!
What are the measurement units of energy?
Calories or joules
For most terrestrial animals, the average daily rate of energy consumption (BMR) for endotherms is _________ times _____ than the SMR for ectotherms, of comparable size, at a given temperature.
2-4 times higher!
What is a mass-specific metabolic rate?
Metabolism, as a function of animal size!
Metabolic rate is proportional to (body mass)^(0.75)
What does mass-specific metabolic rate tell us about the animal size and energy expenditure?
Smaller animals have HIGHER mass-specific metabolic rates, meaning that they are more expensive to operate.
Larger animals run more EFFICIENTLY!
What does the higher metabolic rate of smaller animals translate to?
- Higher oxygen delivery rate
- Higher breathing rate
- Higher heart rate
- Greater relative blood volume
What is acclimation?
The process of adjustment to a SINGLE environmental factor
What is acclimatization?
The process of adjustment to MULTIPLE environmental factors
How do animals respond to changes in the external environment?
They can temporarily remodel their cells and tissues!
Changes in…
- Blood cell count
- Plasma (fluid) composition
- Capillary density
Example: Being at a high altitude
What is the difference between acclimatization and adaptation?
Acclimatization is a PHYSIOLOGICAL PROCESS that occurs in individuals.
Adaptation occurs in populations; it refers to EVOLVING characteristics due to NATURAL SELECTION
What changes over time?
Setpoints and normal ranges! This can be systematical with age, or through a cyclic variation.
What is circadian rhythm?
The cycle that governs physiological changes, occurring roughly every 24 hours.
What is torpor?
A physiological state in which activity is low and metabolism decreases.
Why is torpor important?
It enables animals to SAVE ENERGY while avoiding difficult and dangerous conditions.
What is hibernation?
Long-term torpor - an adaptation to winter cold and food scarcity
What is estivation?
Summer torpor, enabling animals to survive long periods of high temperatures and scarce water
Who exhibits daily torpor?
Small endotherms, who live on ‘rapid’ timelines. They need to do this in order to minimize the costs when feeding isn’t possible!
How do small endotherms exhibit daily torpor?
They drastically reduce their body temperatures, which slows down oxygen consumption.
What is the range of animal forms limited by?
The laws of physics and chemistry.
What are the rates of exchange between the internal and external environments governed by?
-Nutrients, waste products, gases: Proportional to membrane surface are
What is the amount of material exchanged to sustain life governed by?
Cell volume
The opportunity for exchange depends on the _____________ in the body.
Organization of cells
How does exchange differ, between single-celled organisms and multi-cellular organisms?
Single-celled organisms: Has a sufficient membrane surface area in contact with its environment, to carry out all necessary exchange = DIRECT EXCHANGE
Multicellular organisms: Each cell must exchange materials. Can only work if every cell has a suitable aqueous environment.
What is interstitial fluid?
The spaces between cells that are filled with this fluid, which link exchange surfaces to body cells.
What are the two ways in which we can view the body’s organization?
- Bottom-up (Cells –> Organ systems)
2. Top-down: Multilayered basis of specialization and the need for regulation.
What is a particularity of epithelia tissue?
Epithelia is POLARIZED.
- The apical surface faces the lumen (cavity) / outside of the organ = Exposed to fluid, air
- Specialized projections often cover this surface
-Opposite side = Basal surface
What is connective tissue?
A sparse population of cells scattered through an extracellular matrix.
It holds many tissues and organs together and in place.
What are the contents of the extracellular matrix of connective tissue?
Fibroblasts: Secrete fibre proteins
Macrophages: Engulf foreign particles and cell debris
What is the function of nervous tissue?
Functions in the receipt, processing, and transmission of information.
How are responses coordinated and controlled in animals?
HORMONES: Signaling molecules, released from endocrine cells into the blood.
NEURONS: Use electrical signals to carry messages throughout the body.
How does signaling by hormones work?
Stimulus –> Endocrine cell –> Hormone –> Signal travels everywhere via the bloodstream
Response: Limited to cells that have the receptor for that hormone signal
- Can be very fast, or very slow
- Long-lasting effects - hormones remain in bloodstream
How does signaling by neurons work?
Stimulus –> Cell body of neuron –> Signal travels along the axon (nerve impulses)
Response: Limited to cells that connect by specialized junctions to an axon that transmits an impulse
-Signals not broadcasted through entire body - nerve impulses travelling to specific target cells
Most physiological processes in the body are regulated by the _________ systems.
Both the endocrine and nervous systems.
What types of cells can receive nerve signals?
Other neurons, muscle cells, endocrine cells, exocrine cells
What types of signals are involved in nervous system communication?
- Electrical signals: Nerve impulses travel along axons (long-distance)
- Chemical signals: Short-range neurotransmitters
**Very fast signaling!
What are the endocrine and nervous systems best suited for?
Endocrine system: Coordinating gradual changes that affect the entire body
Nervous system: Directing immediate and rapid responses to the environment.
What is bioenergetics?
The overall flow and transformation of energy in an animal, that determines nutritional needs and is related to the animal’s size, activity, and environment.
What are the bioenergetics of an animal?
The external environment provides…
-Organic molecules in food
In the animal body…
- Digestion and absorption
- Nutrient molecules in body cells
- Cellular respiration –> ATP –> Cellular work
- Carbon skeletons –> Biosynthesis: Growth, storage, reproduction
What influences metabolic rate?
- Age
- Sex
- Size
- Activity
- Temperature
- Nutrition
