Human Bio Exam 3

skeletal muscle

voluntary or involuntary, attached to skeleton for movement

cardiac

involuntary, walls of the heart

smooth

involuntary, lining of digestive tract

motor neuron

PNS neurons that receive CNS output information and carry signals to muscle cells

voluntary

conscious control of your body via skeletal muscle contraction

involuntary

unconscious reflexes control muscle contractions

tendon

tissue attaching bone and muscle

muscle fiber

muscle cell-has more than 1 nucleus

sacroplastic reticulum

ER for muscles-stores calcium ions

actin

filament for muscle contraction

myosin

motor protein for contraction- uses ATP

sarcomere

functional unit of straited muscle-actin and myosin

myofibril

contains sarcomere-rod-like tissues in muscle cells

fast-twitch

large diameter fibers, rapid short bursts of contraction, less blood supply, cannot sustain contracts for long, strength training

slow-twitch

small diameter fiber cells that can contract incrementally for a relatively long time, aerobic training

neuromuscular junction

what cause a sarcomere to contract

hypertrophy

the more stress placed on muscle fibers, adapt increasing myofibril content

atrophy

wasting away of muscles breakdown of myofibril content

calcium ions

needed to open and allow for concentration

nerve

contains axons of many neurons wrapped together in protective sheath, information carried to and from CNS

mechanoreceptors

action potential from mechanical change in dendrite region

thermoreceptors

action potential from heat or cold

nociceceptors

action potential from tissue damage or excessive heat

chemoreceptors

action potential from presence of chemicals

cone cells

detect different colors and require brightly lit enviornments

rod cells

detect dim light and are used for low light

lens

change shape to allow for the eye to focus light

fovea

central vision, high clarity

retina

light sensitive sheet of neuronal tissue lining the eye

optic nerve

sends signals to the brain

sound

pressure wave of air

endocrine system

makes hormones used for communication via the bloodstream

hormones

chemical messengers, act on target cells

hypothalamus

control center, maintains homeostasis by sensing changes and issuing commands

thyroid gland

part of the bodies thermoregulation system

pituitary gland

major endocrine gland, controls growth and development and functioning of other endocrine glands

homeostasis

maintenance of constant, optimal internal enviornment

anterior pituitary

makes hormones

posterior pituitary

stores hormones

releasing hormones

stimulate release of other hormones

inhibiting hormones

reduce production of other hormones

puberty

the physical ability to reproduce

chondro

cartilage

osteo

bone

blasts

builder cells

clasts

dissolving cells

cytes

mature cells

chondroblasts

build cartilage

osteoclasts

break down bone

osteocytes

are mature cells in bones

soma

body cells

germline

reproductive cells, egg and sperm

sexual reproduction

2 parents

asexual reproduction

single parent

corpus luteum

produces progesterone that prepares the uterus for the possibility of pregnancy

anisogamy

different size of sex cells that drives different reproductive interests between males and females

gene dosage

the # of copies of a gene present in a cell of an organism

trisomy

three copies of the same chromosome instead of two

monosomy

only one chromosome is present

meiosis

produces cells that may participate in sexual reproduction

crossing over

occurs between chromosomes and creates a new combo of genes

independent assortment

chromosomes are not dependent on one another and assort randomly

gene locus

location of a specific pair of genes

alleles

alternative versions of the same gene, arise by mutation or can be introduced via migration

mutation

generates diversity by adding new alleles to the population if transmitted through the germline

gene flow

the movement of alleles from one population to another

genetic drift

random fluctuations of allele frequency change in a population

evolution

when the genetic composition of a population changes over time

natural selection

organisms with traits better suited to their environment survive and produce more