05. Animal Form and Function [DEFINITIONS] Flashcards
Ventricles
Ventricles are the four irregular shaped cavities formed by the central canal in the brain.
Autonomic Nervous System
The nervous system that controls the involuntary activities of the body consisting of neurons which carry impulses to control activities of smooth muscles, cardiac muscles, and glands is the autonomic nervous system.
Motor System
The nervous system that consists of neurons that carry nervous impulses to skeletal muscles controlling voluntary activities is the motor system.
Resting Potential
When a neuron is at rest (when not sending a signal/non conducting), the membrane potential is called the resting potential.
Action Potential
An action potential occurs due to a change in membrane potential above a threshold value due to a stimulus.
Depolarization
Depolarization is a change in the cell’s membrane potential such that the inside of the membrane is made less negative relative to the outside which is resulted from Na+ inflow in response to a stimulus.
Repolarization
Repolarization is when sodium channels close, blocking Na+ inflow. Here, most potassium channels open permitting K+ outflow, making the inside of the cell negative.
Hyperpolarization
Hyperpolarization is when sodium channels are closed but potassium channels are opened, resulting in the inside of the membrane being more negative.
Refractory Period
A refractory period is the short time immediately after an action potential where the neuron cannot respond to another stimulus, because of the inactivation of sodium channels. This prevents the reverse conduction of an impulse in an axon.
Synapse
A synapse is the junction where a neuron (presynaptic cell) communicates with another cell (postsynaptic cell) across a narrow gap (synaptic cleft)
Postsynaptic Cell
A postsynaptic cell is a cell that may be another neuron, muscle cell or secretory cell.
Chemical Synapse
The junction where one neuron communicates with the next cell using a chemical (neurotransmitter) is called a chemical synapse.
Electrical Synapse
Some neurons can also communicate through direct electrical connections. This is called an electrical synapse.
Neurotransmitters
Neurotransmitters are the molecules that are released from the synaptic terminals of presynaptic neuron and diffuse across the synaptic cleft, bind with the receptors at the postsynaptic membrane triggering a response.
Reflex Arc
Reflex arc is the functional unit of the vertebrate nervous system.
Sensory Neuron
A sensory neuron transmits impulses from a sensory receptor to the central nervous system.
Interneuron
The central nervous system synapses with an associated neuron called interneuron.
Motor Neuron
When an impulse is transmitted to a motor neuron by the interneuron, the motor neuron conveys the signal to effector tissues/organs.
Sensory Receptor
A sensory receptor is a specialized structure such as a specialized cell, organ or a subcellular structure which can detect a specific stimulus and convert the stimulus energy to a changing membrane potential to be transmitted to the central nervous system as action potentials for sensory perception and interpretation.
Chemoreceptors
Chemoreceptors are sensory receptors that respond to chemical stimuli
Taste receptors
Receptors that detect the five basic sensations (sweet, sour, bitter, salt, and umami- savory taste) are taste receptors
Olfactory Receptors
Olfactory receptors are cells located within the epithelium of the upper portion of the nasal cavity detecting odors
Thermoreceptors
Specialized temperature sensitive receptors which detect heat and cold on the body surface and in the internal environment of the body are thermoreceptors.
Photoreceptors
Photoreceptors are sensory receptors that are sensitive to light
Mechanoreceptors
Mechanoreceptors are receptors that respond to stimuli arising from mechanical energy deformation such as pressure, touch, stretch, motion and motion.
Pain Receptors
Pain receptors detect stimuli that reflect harmful conditions that could arise from extreme pressure, temperature, and certain
chemicals that could damage the tissues.
Lens
The lens is an elastic, biconvex, transparent disc made up of protein enclosed within a transparent capsule which lies immediately behind the pupil
Retina
the retina is the innermost lining of the eye consisting of three layers (outer pigmented epithelium, middle photoreceptive layer and inner layer with neurons)
Monocular Vision
Seeing the visual field using only one eye is called monocular vision.
Binocular Vision
Seeing the visual field using two eyes with greater overlapping fields of view is called binocular vision.
Epidermis
Epidermis is the outermost layer of skin which consists of stratified keratinized squamous epithelium. It’s not supplied with blood vessels.
Dermis
Dermis is composed of areolar connective tissue with a matrix that contains collagen fibers interlaced with elastic fibers.
Endocrine Glands
Endocrine Glands are ductless glands consisting of groups of specialized cells which secrete hormones (chemical messengers) that diffuse directly into the bloodstream and reach the specific target organs/tissues that may be located quite distantly.
Hormone
Hormones are specific types of signaling molecules secreted by an endocrine gland/endocrine cells and travels in the blood on specific target cells elsewhere in the body, changing the target cell functioning.
Homeostasis
Homeostasis is a steady state condition where body’s internal environment remains relatively constant within narrow physiological limits despite significant changes in the external environment.
Osmoregulation
Osmoregulation is the process of maintaining water and salt balance (osmotic balance) across membranes within the body’s fluids relative to the surrounding.
Reproduction
Reproduction is a biological process through which a new generation of individuals is produced from the existing organisms.
Asexual Reproduction
Asexual reproduction is a mechanism through which new individuals are generated from a single parent without the fusion of egg and sperm. It allows the rapid multiplication of individuals from single parents and relies entirely on mitotic cell division.
Budding
Budding is a form of asexual reproduction in which new individuals arise from outgrowths of an animal
Fragmentation and Regeneration
This is a form of asexual reproduction which involves breaking of the body or part of the body into several pieces, followed by the growth of a separate individual from each piece. Here, each fragment develops into a complete animal by the regrowth of lost body parts (regeneration)
Parthenogenesis
Parthenogenesis is an unusual form of asexual reproduction in which an egg develops into a complete individual without being fertilized.
Sexual Reproduction
Sexual reproduction is a mechanism through which a new individual is developed from a diploid zygote as a result of the fusion of two haploid gametes (the sperm and the egg) which are produced by two individuals (the male and the female parents respectively)
Fertilization
The union of an egg and a sperm (gametes) culminating in fusion of their nuclei is called fertilization. This could be internal or external
Internal Fertilization
In internal fertilization, sperms are deposited in or near the female reproductive tract and fertilization occurs within the female reproductive tract.
Spermatogenesis
Spermatogenesis is the process of male gamete formation which includes formation of spermatocytes from a spermatogonium, meiotic division of the spermatocytes, and transformation of the four resulting spermatids (from each spermatocyte) into spermatozoa (sperm)
Semen
Semen is the fluid that contains a mixture of sperms and the secretions of three sets of accessory glands discharged from the urethra during ejaculation.
Seminal Vesicles
The seminal vesicles are a pair of two small pouches that produce a thick, yellowish fluid that is expelled during ejaculation.
Prostate Gland
Prostate gland is found below the urinary bladder and secretes a thin, milky fluid directly into the urethra through small ducts.
Bulbourethral Glands
Bulbourethral glands are a pair of small glands found along the urethra below the prostate and secrete a clear alkaline mucus that is able to neutralize any acidic urine remaining in the urethra and lubricates the lining of the urethra.
Ovaries
Ovaries are organs found on either side of the uterus and held in place in the abdominal cavity by ligaments.
Oviducts
The oviduct or the fallopian tube is a structure that extends from the uterus toward a funnel like opening at each ovary.
Uterus
The uterus or the womb is a thick, pear shaped chamber with a highly vascularized inner lining (endometrium) and muscular walls which allows it to expand during pregnancy to accommodate the fetus
Vagina
The vagina is a muscular but elastic chamber with a stratified epithelium connected to external and internal organs of reproduction. This is the site where sperm is deposited and also serves as the birth canal.
Uterine cycle
The uterine cycle consists of changes that occur about once a month in the uterus.
Ovarian Cycle
The cycle that controls the cyclic changes in the uterus is the ovarian cycle.
Menopause
Menopause is the cessation of ovulation and menstruation in a woman where the ovarian supply of oocytes runs out and estrogen production by the ovary decreases.
Blastocyst
About five days after fertilization, a large fluid filled cavity is formed surrounding the ball of cells. With the formation of the cavity, this developing stage is referred to as the blastocyst. This includes the structures of inner cell mass and the trophoblast formed by the further rearrangements of the cells in the blastocyst.
Chorion
Chorion becomes the main embryonic portion of the placenta which is the structure for exchange of materials between the fetus and mother, and protects the embryo/fetus from immune responses of the mother.
Amnion
Amnion is a protective membrane surrounding the embryo/fetus creating a fluid filled cavity which serves as a shock absorber and helps prevent desiccation.
Yolk Sac
The yolk sac contributes to the cells that will become blood cells until the fetal liver takes over and is also the source of primordial germ cells that migrate to the developing gonads
Allantois
Allantois is a small outer-pouching of the yolk sac that serves as an early site for blood formation and is also associated with the development of the urinary bladder.
Placenta
The placenta is a disc shaped organ formed by two parts: embryonic/fetal portion formed by chorionic villi of the chorion and maternal portion formed by the endometrium.
Umbilical Cord
The umbilical cord is a flexible cord-like structure containing blood vessels and attaches embryo/fetus to the placenta during gestation.
Pregnancy
Pregnancy or gestation is the condition of carrying one or more developing offspring inside the uterus of a female
Labor
Labor is a series of strong, rhythmic uterine contractions that push the fetus and placenta out of the body
Lactation
Lactation is the secretion and ejection of mother’s milk from the mammary glands
Infertility
Infertility is the inability to conceive offspring.
Hydrostatic Skeleton
The hydrostatic skeleton is a fluid filled body cavity which is enclosed by the body wall.
Exoskeleton
The exoskeleton is a rigid outer covering of the body of the animal which acts as a skeleton.
Endoskeleton
The endoskeleton is a hard skeleton which is buried in the soft tissues of the animal. These can include plates of calcium carbonate (in echinodermates) or bones and cartilage (in chordates)
Sternum
The sternum is a long flat bone that forms the anterior part of the thoracic cage (which is made up of sternum, ribs and thoracic vertebrae)
Simple Squamous Epithelium
It is a single layer with plate-like cells which is thin and leaky. Found in places where materials exchange by diffusion.
Simple Cuboidal Epithelium
It is a single cell layer with dice shaped cells specialized for secretion found in kidney tubules, and glands like thyroid and salivary glands.
Simple Columnar Epithelium
It is a single layer with large brick-shaped cells often found in places where secretion or active absorption is important (ex: intestinal lining)
Stratified Squamous Epithelium
Connective Tissue
Connective tissues are the most abundant tissues in the body that help connect organs and tissues together structurally and functionally.
Loose Connective Tissue / Areolar Tissue
A generalized type of connective tissue containing fibroblasts, macrophages, mast cells, leukocytes and fat cells, loosely arranged and wavy in nature.
Fibrous Connective Tissue / Dense connective Tissue
Densely packed connective tissue containing collagen fibers where the matrix is relatively reduced with fewer cells. (fibrocytes)
Adipose Tissue
Specialized type of connective tissue packed with adipose cells.
Blood Tissue
It is a specialized type of connective tissue in which the matrix is not secreted by the cells and fibers.
Cartilage
This tissue consists of a matrix composed of chondroitin sulphate which is a rubbery protein-carbohydrate complex.
Bone
It is a mineralized connective tissue with a matrix that consists of collagen fibers and inorganic salts.
Muscle Tissue
Muscle tissues is responsible for movement and are made of cells composed of actin and myosin proteins
Nervous Tissue
A tissue containing neurons and glial cells
Neuron
Basic structural unit of the nervous system containing a cell body, dendrites and an axon.
Neuroglia / Glial Cells
Neuroglial cells are supportive cells of neurons