homeostasis Flashcards
what is homeostasis?
a basic characteristic of living things, it is the steady state of physiological conditions in the body
what are the basic mechanisms of homeostasis?
feedback regulation: stimulus -> response -> increase or reduce stimulus -> stimulus –>response -> increase or reduce stimulus…
what are the two types of feedback regulation?
negative feedback, which is where the response to stimulus REDUCES the stimulus (more common) and positive feedback which is when the response to stimulus AMPS the stimulus
what is osmoregulation?
the process by which organisms regulate the concentration of water & solutes in their bodies to maintain internal stability (homeostasis) in relation to the surrounding environment
what is a paramecium and how does its osmoregulation work?
a unicellular protist that is generally aquatic. in a hypotonic environment (more solute in cell than outside) the water moves inward via osmosis. the contractile vacuole is an organelle that is used to pump water out to maintain water balance and prevent lysis.
what is a jellyfish phylogeny and how does its osmoregulation work?
jellyfish belong to the phylum Cnidaria, which includes animals with simple body plans. They have a diploblastic development, meaning their bodies are composed of two adult tissue layers: the epidermis (outer layer) and the gastrodermis (inner layer). Jellyfish do not have a dedicated circulatory system like more complex animals. Instead, all internal fluids, including water, nutrients, and waste products, move through the body via diffusion.
how does homeostasis work for all organisms?
all organisms must regulate internal enviornment and exchange with outside enviornment. the mechanisms depend on enviornment and type of organism
how does osmoregulation work for humans?
humans have evolved from marine environments and must maintain conditions similar to the marine environment internally, including gasses, pH, etc. they have various adaptions for terrestrial life such as:
- the amniotic sac for reproduction/development
- scales/skin for water balance
- excretory system for waste removal
what are homeostasis constraints in animals?
constraints on animals body size/shape include limitations from physical laws like strength, diffusion, movement, and heat exchange.
what is an example of constraints on animals?
the shape of swimming animals is contrainued by the properties of water, which is denser and more viscous (thick) than air. these constraints result in animals evolving smooth and streamlined shapes to reduce drag and move more efficiently through water. there are diverse organisms in the same environment that can exhibit similar adaptions (convergent evolution)
what is the significance of animals not being closed systems?
they exchange nutrients, gases, waste, etc with the environment
how are substances like nutrients, gases, and waste exchanged with the environment?
through a process that relies on their ability to dissolve in water and move across cell membranes
what are the consequences of the exchange process on the body plan of animals?
the exchange influences the body plans
what is the difference between coelomates and acoelomates?
coelomates have a body cavity that can accomodate internal organs while acoelomates lack a body cavity
what is the hiearchial organization of animals?
starts with cells as the basic unit, groups of cells with similar structure and function make up tissues, different tissues organized into a functional unit are organs, organs that work together is an organ system
what are the four main types of tissues in animals?
epithelial, connective, muscle, and nervous
what are examples of homeostasis processes?
our bodies employ various strategies to maintain stability, or homeostasis, in response to changing external conditions. When it’s cold, we may shiver internally, generating heat through muscle contractions to maintain our internal body temperature. Conversely, when it’s hot, we might sweat externally, using evaporation to cool down and regulate our body temperature.
what are two strategies used for the maintenance of homeostasis?
regulators and conformers, many animals will regulate some conditions and conform to others
what is a regulator?
maintain internal conditions within a narrow range, regardless of external conditions. They use physiological mechanisms to control internal variables such as body temperature, blood pH, and ion concentrations. For example, humans are regulators of body temperature, maintaining it around 98.6°F (37°C) regardless of external temperature changes.
what are conformers?
. They do not actively regulate internal variables but instead conform to the external environment. For example, some aquatic organisms, like fish, allow their body temperature to match the temperature of the water they are in.
what are adaptions animals have for exchange with the environment?
branching, folding, internal fluids
how are variables maintained for regulators?
variables are kept at or near a specific value called a set point or a normal range (variable has upper and lower limit) through negative feedback mechanisms
what is the process of negative feedback in regulators?
when an internal variable deviates from the set point, a stimulus triggers a response that brings the variable back to its normal range. this process involves a sensor, control center, and response mechanism.
what are the two systems that coordinate responses to stimuli?
endocrine and nervous
