66 terms

IB Biology Topic 6

Humans as organisms SL
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pathogen
any disease-producing agent (especially a virus or bacterium)
antigen
any surface protein that may elicit an immune response or cell recognition
digestion
the process where food is converted into smaller molecules that can be absorbed into the body
enzymes
globular proteins that speed up chemical reactions in the body
amylase
enzyme found in saliva and pancreatic juice that breaks the chemical bonds in starches
protease
enzyme that speeds up the breakdown of proteins into amino acids. produced by the stomach, small intestine, and pancreas.
lipase
an enzyme secreted by the pancreas that catalyzes the breakdown of fats into individual fatty acids
stomach
An organ of the digestive system that contains acid, protease enzymes and churns food.
small intestine
organ that completes the chemical digestion of food and absorbs the nutrients
large intestine
the last section of the digestive system, where water is absorbed from food and the remaining material is eliminated from the body
absorption
the process of absorbing nutrients into the body after digestion
assimilation
the process where cells absorb nutrients and use them for what the body needs
villi
fingerlike projections of the small intestine (illeum) that helps it absorb nutrients
heart
multi-chambered, muscular organ that pumps blood throughout the body
coronary arteries
arteries that supply oxygen-rich blood to the heart muscle
myogenic
Describes muscle tissue (heart muscle) that generates its own contractions.
pacemaker
a specialized bit of heart tissue that controls the heartbeat
nerves
any bundle of fibers belonging to the nervous system that transmits sensations and messages between the brain and other parts of the body
medulla
part of the brain nearest the spinal cord (base of brainstem) which controls breathing, heart rate and blood pressure.
adrenaline
affect sympathetic nervous system in stress response
arteries
thick walled, elastic blood vessels that carry blood away from the heart
capillaries
the smallest blood vessels which connect the smallest arteries with the smallest veins.
Diffusion can easily occur through the thin walls of capillaries
veins
blood vessels with valves, that carry blood back to the heart
plasma
liquid portion of blood made up of water, dissolved salts, proteins, hormones, etc.
erythrocyte
A red blood cell;
with hemoglobin, carries oxygen in the blood.
leucocyte
white blood cell
involved in immune response
platelet
a blood cell fragment that is important in forming blood clots
antibiotics
chemicals that inhibit the growth of microorganisms (bacteria and fungi)
virus
a nonliving, infectious particle composed of a nucleic acid and a protein coat.
bacteria
Prokaryotic, single celled organisms.
phagocytosis
a type of endocytosis in which substances are taken up by a cell, forming a vesicle.
antibodies
Protein that is produced by lymphocytes that attaches to a specific antigen which aids in destroying infectious diseases
HIV
the virus that causes acquired immune deficiency syndrome (AIDS); it replicates and kills Helper T-cells
AIDS
a syndrome caused by the human immunodeficiency virus (HIV) that renders immune cells ineffective, permitting opportunistic infections.
ventilation
the bodily process of inhalation and exhalation; of air - containing oxygen and carbon dioxide.
gas exchange
exchange of gases between air in alveoli and blood.
O2 for respiration and its waste product, CO2
Alveoli
tiny sacs of lung tissue specialized for the movement of gases between air and blood
trachea
The windpipe; a passage through which air moves in the respiratory system.
lungs
two spongy organs, located in the thoracic cavity enclosed by the diaphragm and rib cage.
bronchi
two short branches located at the lower end of the trachea that carry air into the lungs.
bronchioles
progressively smaller tubular branches of the airways
diaphragm
Large, flat muscle at the bottom of the chest cavity that helps with breathing
Central Nervous System
the brain and spinal cord;
Peripheral Nervous System
the sensory and motor neurons that connect the central nervous system to the rest of the body
dendrite
branching extensions of a neuron that receive messages and conduct impulses toward the cell body
axon
the extension of a neuron, which conducts impulses away from the cell body
myelin sheath
a layer of fatty tissue surrounding the fibers of many neurons;
motor end plates
Terminal filaments of motor neurons that form a synapse with a muscle cell
nerve impulse
the electrical discharge that travels along a nerve fibre
relay neuron
a neuron which connects sensory neurons to motor neurones in neural pathways
motor neuron
this carries impulses from the CNS to the muscles.
resting potential
the potential difference between the two sides of the membrane of a nerve cell when the cell is not conducting an impulse, -70mV
action potential
a neural impulse; the local voltage change across the membrane as a nerve impulse is transmitted.
endocrine system
collection of glands that secrete hormones into the blood which regulate growth, development, and homeostasis
homeostasis
process by which organisms maintain a relatively stable internal environment
negative feedback
a mechanism where the change in a physiological state triggers a response that reverses the initial change.
diabetes
a condition in which the pancreas fails to produce enough insulin or the body's cells cannot use insulin properly,
male reproductive system
Produces male sex cells (sperm) and mail hormones (e.g. testosterone), transfers sperm to the female
female reproductive system
produces female sex cells (oocytes) and female hormones (e.g. estrogen and progesterone); recieves sperm from male; site of fertilization of an oocyte; site of growth and development of an embryo and fetus.
FSH
Follicle Stimulating Hormone; a gonadotropic hormone that is secreted by the anterior pituitary and stimulates growth of Graafian follicles in female mammals, and activates sperm-forming cells in male mammals
LH
Luteinizing Hormone, a gonadotropic hormone that is secreted by the anterior pituitary; stimulates ovulation in female mammals and androgen release in male mammals
estrogen
female sex hormone, secreted by the ovary and responsible for typical female sexual characteristics
progesterone
A hormone produced by the ovaries which acts with estrogen to bring about the menstral cycle; prepares and maintains uterus for pregnancy
endometrium
the mucous membrane that lines the inner wall of the uterus
In Vitro Fertilization
The most common assisted reproduction procedure, in which a woman's eggs are mixed with sperm in culture dishes (in vitro) and then carefully inserted into a woman's uterus.
testosterone
the male sex hormone. testosterone in males stimulates the growth of the male sex organs in the fetus and the development of the male sex characteristics during puberty