Unit 2 bio test

PNS

Peripheral Nervous System, consisting of all nerve structures outside the brain and spinal cord which controls involuntary bodily functions.

CNS

Central Nervous System, brain and spinal cord, responsible for processing and transmitting information throughout the body.

Sensory Neurons

carry to stimulus info into the CNS

Motor Neurons

Carry the signal to the proper effector to produce the required response

Neurotransmitters

chemicals produced to make the effector carryout the response

regulation

The process of controlling body systems to maintain ideal function and homeostasis: depends on two systems: Nervous/Endocrine

Stimulus

a detectable change (physical or chemical) in the environment (external or internal) of an organism that results in some activity in response

Control Center

Brain/gland that senses stimulus message and decides on a response: sends a message to an effector by nerve signal or hormone message

Effector

organ/gland/muscle that performs an action; sweat glands begin secreting sweat

Response

any behavior of a living organism that results from an external or internal stimulus

Accessory digestive organs are

Pancreas, gallbladder, and liver

Mouth

Food is broken into smaller pieces: saliva moistens food to form bolus (ball); Amylase enzyme starts breakdown of carbohydrates to sugars (mechanical and chemical digestion)

Pharynx

Area behind uvula: bolus moves through pharynx to esophagus (no digestion)

Esophagus

muscular tube that uses peristalsis to squeeze the bolus from the pharynx to the stomach

Stomach

Bolus mixed/ground by strong muscles contractions; enzymes (pepsin) and HCI acid react to start break down of protein molecules; chyme= soupy mixture (both mechanical and chemical) 

Liver

Produces bile; bile emulsifies (separates into droplets) fats to promote digestion

Gallbladder

Stores bile that was produced in liver; bile moves into small intestine through duct

Pancreas

Produces digestive enzymes including: amylase, lipase, nuclease, protease; enzymes enter small intestine through duct (contributes to chemical digestion for “everything”

Small Intestine

First section (duodenum) completes most enzymatic digestion; produces enzymes that join pancreatic enzymes

Second section (jejunum) finalizes digestion and absorption begins

Final section (Ileum) completes absorption, aided by villi/microvilli

Large intestine

Water reabsorption occurs; feces formed

Mechanical digestion

increases surface area for chemical digestion to occur (no change in chemical identity of the substance

Chemical digestion

chemical processes that break food particles down into simpler molecules; require enzymes and other digestive agents (change in chemical identity)

Villi/microvilli

maximize surface area in the small intestine for absorption of digested food

epiglottis

small flap, closes over trachea while swallowing

trachea

wind pipe

Bronchi

two short tubes that take air into right and left lungs

Bronchioles

smaller air tubules within the lungs

Diaphragm

sheet-like muscle that separates the thoracic cavity from the gut

alveoli

location of gas exchange; tiny air sacs found at the ends of the bronchioles

hemoglobin

protein molecule in red blood cells responsible for carrying oxygen

red blood cells

contain hemoglobin that bonds to oxygen to carry it throughout the body (made in bone marrow)

white blood cells

immune response, made in bone marrow, spleen, and lymph nodes, several types (engulf microorganisms, produce antibodies)

Platelets

help form blood clots; fragments of cells produced by bone marrow

what are the three types of blood vessels?

arteries, veins, and capillaries

arteries

large, muscular vessels that carry blood away from the heart; very elastic to deal with high pressure of pumped blood

veins

much less muscular, carry blood under low pressure back to heart; contain one-way valves which keeps blood moving toward the heart

capillaries

smallest blood vessels; walls are only 1 cell thick, diffusion of O2, CO2, nutrients, wastes, ect

Hormone

delivered by bloodstream, chemical substances that act like messenger molecules in the body

Negative Feedback loop

Nerve or endocrine response that negates stimuli to help maintain homeostasis in the body

Positive Feedback loop

initial stimulus is amplified ex. body needs to dispose of waste, body amplifies it so the person has to release the waste.