sensory neuron

type of nerve cell that receives information

from sensory receptors and conveys signals to central

nervous system

stimulus (pI. stimuli)

signal to which an organism

responds

interneuron

: type of neuron that processes information

and may relay information to motor neurons

motor neuron:

 type of nerve cell that carries directions

from interneurons to either muscle cells or glands

response

ganglion (pI. ganglia):

cerebellum

: part of the brain that coordinates movement

and controls balance

cerebrum:

part of the brain responsible for voluntary activities

of the body; "thinking" region of the brain

exoskeleton

: external skeleton; tough external covering

that protects and supports the body of many invertebrates

ligament:

tough connective tissue that holds bones

together in ajoint

oviparous:

species in which embryos develop in eggs outside

a parent's body

ovoviparous:

species in which the embryos develop within

the mother's body but depend entirely on the yolk sac of their eggs

placenta

: specialized organ in placental mammals through

which respiratory gases, nutrients, and wastes are exchanged between the mother and her developing young

viviparous:  

animals that bear live young that are nourished

directly by the mother's body as they develop (822)

nymph:

immature form of an animal that resembles the

adult form but lacks functional sexual organs

pupa:

stage in complete metamorphosis in which the larva

develops into an adult

amniotic egg

 egg composed of shell and membranes that

creates a protected environment in which the embryo can develop out of its mother's body

mammary gland:

 gland in female mammals that produces

milk to nourish the young

endocrine gland:

 gland that releases its secretions (hormones)

directly into the blood, which transports the secretions

to other areas of the body

ectotherm:

animal whose body temperature is determined

by the temperature of its environment

endotherm:

animal whose body temperature is regulated,

at least in part, using heat generated within its body

Sensory systems range from individual

sensory neurons to sense organs that contain both sensory neurons and other cells that help gather information .

hydrostatic skeleton:

skeleton made of fluid -filled body

segments that work with muscles to allow the animal to

move

endoskeleton:

internal skeleton; structural support system

within the body of an animal

Animals have three main kinds of skeletal systems:

hydrostatic

skeletons, exoskeletons, and endoskeletons.

molting:

process of shedding an exoskeleton and growing a

new one

Joint:

Sexual reproduction

maintains genetic diversity in a

population by creating individuals with new combinations of genes

internal fertilization,

eggs are fertilized inside the body of the eggproducing

individual.

external

fertilization,

eggs are fertilized outside the body of the egg-producing

individual.

metamorphosis:

process of changes in shape and form of a

larva into an adult

Amnion

a fluid·filled sac that surrounds and cushions

the developing embryo. It

produces a protected, watery

environment.

Chorion

regulates the transport of oxygen from the

surface of the egg to the embryo and

the transport of carbon dioxide,

one product of respiration, in the

opposite direction .

Yolk Sac

This baglike structure

contains a yolk that

serves as a nutrient-rich

food supply for the embryo.

Allantois

stores the waste produced by the

embryo. It later fuses with the chorion and serves

as a respiratory organ

The three groups of mammals

-monotremes, marsupials,

and placentals-

Reproduction - monotremes

combines reptilian and mammalian traits. Like a reptile, a female monotreme lays soft-shelled, amniotic eggs that are incubated outside her body. The eggs hatch in about ten days. But like other

mammals, young monotremes are nourished by milk produced by the mother's mammary glands. Female monotremes secrete milk, not through well-developed nipples like other mammals, but through pores on the surface of the abdomen

Marsupials

 bear live young that usually complete their development in an external pouch. Marsupial young are born at a very early stage of development.

Inside the marsupium, the young spend months attached to a nipple.

Placental mammals

 named for the placenta, which allows nutrients,

oxygen, carbon dioxide, and other wastes to be exchanged between the embryo and the mother. The placenta allows the embryo to develop

for a long time inside the mother and allows it to be born at a fairly advanced stage of development .