Animal Physiology I - Body Plans and Nervous Systems

Comprehensive vocabulary flashcards covering animal body plans, bioenergetics, homeostasis, and the physiology of the nervous system based on lecture notes.

Proximate level of causation

Focuses on the mechanisms responsible for a function.

Ultimate level of causation

Focuses on how physiological systems evolved and how they impact fitness.

Gradients

Exist when the concentration of an ion or molecule, or the amount of electrical charge, differs from one area to another.

Radial symmetry

An arrangement where body parts are organized around a central axis and can be bisected into two equal halves in any 2-D plane.

Bilateral symmetry

An arrangement where the body has right and left halves that are mirror images, and only the sagittal plane bisects the animal into two equal halves.

Surface area-to-volume ratio

A physical constraint on cell size that decreases as a cell gets larger, necessitating multicellularity in larger organisms.

Porifera

Sponges that lack defined tissues and organs and possess the ability to disaggregate and aggregate their cells.

Eumetazoa

Animals with distinct, well-defined tissues and irreversible differentiation for most cell types.

Basal Metabolic Rate (BMR)

The average amount of energy used by an organism in a non-active state.

Sagittal plane

A plane that divides the body into right and left portions.

Frontal (Coronal) plane

A plane that separates the front of the body from the back.

Transverse (Horizontal) plane

A plane that divides an animal into upper and lower portions, also called a cross section.

Epithelia

A type of animal tissue that lines cavities, open spaces, and surfaces.

Simple Epithelium

Epithelial tissue consisting of a single layer of cells.

Stratified Epithelium

Epithelial tissue consisting of multiple layers of cells.

Connective Tissue

Tissues consisting of cells called fibroblasts embedded in a non-cellular matrix, used to connect other tissues or provide structure.

Fibroblasts

Cells found within connective tissue that secrete the ground substance fibers.

Skeletal muscle

Striated muscle tissue under voluntary control.

Smooth muscle

Involuntary muscle tissue with no striations, typically having tapered fibers and being mononucleate.

Cardiac muscle

Involuntary, striated muscle tissue containing intercalated discs.

Homeostasis

The process of maintaining internal conditions around a set point.

Acclimatization

Changes in one organ system to maintain a set point in another organ system, such as adjustments at high altitudes.

Negative Feedback Loop

A biological mechanism that counteracts internal changes by reversing the direction of the change.

Positive Feedback Loop

A mechanism that maintains or strengthens a response to a stimulus, such as the release of oxytocin during childbirth.

Endotherm

An organism capable of internal generation of heat.

Ectotherm

An organism that depends on external sources for body heat.

Cephalization

The concentration of ganglia and sensory receptors in the head region of an animal.

Central nervous system (CNS)

The division of the nervous system that includes the brain and spinal cord.

Peripheral nervous system (PNS)

The division of the nervous system containing cranial and spinal nerves that lies outside the CNS.

Dendrites

Specialized structures of a neuron that receive signals from sensory receptors.

Axon

The part of a neuron that conducts nerve impulses away from the cell body.

Motor Neurons

Neurons that accept nerve impulses from the CNS and transmit them to muscles or glands.

Sensory Neurons

Neurons that accept impulses from sensory receptors and transmit them to the CNS.

Interneurons

Neurons that convey nerve impulses between various parts of the CNS.

Glial Cells

Cells that support, protect, and nourish neurons, outnumbering them 10 to 1 in the brain.

Membrane potential

The difference in total charge between the inside and outside of a cell.

Voltage-gated ion channels

Channels that regulate the relative concentrations of different ions inside and outside the cell to maintain membrane potential.

Synaptic cleft

The gap between the presynaptic neuron and the postsynaptic neuron where neurotransmitters diffuse.

Enteric nervous system (ENS)

The nervous system located in the digestive tract responsible for autonomous functions independent of the brain.