college biology human body systems chapters 35-40
TRANSCRIPT
College BiologyHuman Body SystemsChapters 35-40
Organization in Multi-cellular Organisms
1. Cell
2. Tissue – group of similar cells that perform a particular function
3. Organ – group of tissues that work together
4. Organ System – group of organs that work together
5. Organism
11 Organ Systems
Feedback Control Feedback systems - control
& regulate body processes. Organ systems work together,
use feedback to maintain homeostasis
Homeostasis = stable internal conditions
Uses the consequences of the process (too much or too little produced) to control the rate at which the process occurs
Consists of a sensor, a control center, and an effector
Feedback Control Example:
Body Temperature
Digestive System
Structures: mouth, pharynx, esophagus, stomach, small intestine, large intestine
Accessory Structures: salivary glands, pancreas, liver, gallbladder
Functions: Acquiring nutrients: Breaks down
large food molecules into simpler molecules that can be used by the cells of the body
Absorbs nutrients and eliminates waste
Pathway of Food
Mouth: Chewing mechanically (physically) breaks down foodSalivary Glands: Saliva contains enzymes that break down starch
(carbohydrate)Pharynx: Beginning of throat Connects mouth to esophagus
Esophagus: Muscle contractions
(peristalsis) push food down toward the stomach
Stomach: Churns food (mechanical
digestion) Enzymes break down
proteins Does NOT absorb any
nutrients Secretes acid
Small Intestine: Chemical digestion of carbs, proteins, and lipids
finishes Carbs, proteins, and lipids are absorbed into the blood Liver, gallbladder, and pancreas secrete enzymes into
it for chemical digestion Very long and lined with villi, “wrinkles” that increase
surface area for more absorption
Accessory OrgansFood never enters these organs!Pancreas: Secretes enzymes into small intestine to break down
nutrientsLiver: Stores extra glucose as the polysaccharide glycogen Makes bile (which breaks down fats) Filters out toxins (alcohol, drugs, bacteria, old cells) from
bloodGallbladder: Stores bile made by the liver
Large Intestine (including rectum and anus):
Absorbs water from waste and then eliminates waste as feces
Close-up of the Digestive System
Summary of Food Breakdown
Respiratory System
Structures: nose, pharynx, larynx, trachea, bronchi, bronchioles, lungs
Functions: Gas exchange
Provides oxygen needed for cellular respiration
Removes excess carbon dioxide from the bloodstream
Breathing
Inhalation: “breathing in.” Exhalation: “breathing out.”
Accomplished by expanding/contracting diaphragm muscle
Pathway of air: nose, pharynx, larynx, trachea, bronchi (lungs), bronchioles (lungs).
Tiny air sacs, alveoli, are at the end of each bronchiole, surrounded by blood capillaries.
Alveoli = site of gas exchange. Oxygen diffuses from alveoli to blood, carbon dioxide diffuses from blood to alveoli
Gas Exchange in the Lungs
Circulatory System
Structures: heart, blood vessels, blood
Functions: Transport: Brings oxygen,
nutrients, and hormones to cells
Helps fight infection Regulates body temperature
Blood Contents Plasma – fluid part of blood
that carries nutrients, enzymes, hormones, and wastes
Red blood cells – contain the iron-based protein hemoglobin, which carries oxygen Made in bone marrow
White blood cells – attack foreign substances
Platelets –help blood clot
Circulatory System: Structures
Heart - Made of muscle, pumps blood through body
Arteries – carry blood away from heart to capillaries Capillaries – tiny vessels that allow diffusion of
materials between blood and cells; where arteries and veins meet
Veins – carry blood back to heart from capillaries
Blood Flow De-oxygenated blood is
pumped from the heart to the lungs where it picks up oxygen.
Oxygenated blood flows back to the heart.
Oxygenated blood pumped out to body cells to deliver oxygen and pick up carbon dioxide.
De-oxygenated blood flows back to the heart and the cycle restarts.
Nervous System
Structures: brain, spinal cord, peripheral nerves (sensory and motor)
Function: Controls and coordinates
functions throughout the body in response to internal and external stimuli
Neurons A message called an action potential is transmitted by
nervous cells (neurons). Action potentials are electrical signals. Neurons have 3 parts:
• Dendrites – receive message (action potential) • Cell body – contains the nucleus and other normal
organelles• Axon – sends action potential message to another cell
Synapse = the space between the end of one neuron and the start of the next
Neurons transmit messages by sending chemicals (neurotransmitters) across the synapse.
Muscular System
Structures: Skeletal muscle, smooth muscle, cardiac muscle
Functions: Movement
Works with skeletal system to produce voluntary movement
Helps circulate blood and move food through the digestive system
Three Types of Muscle: Skeletal: attached to bones by tendons;
voluntary Smooth: controls digestion, breathing,
circulation; involuntary Cardiac: heart muscle; involuntary
Muscles cause movement by contracting (getting shorter) or relaxing (getting longer)
Example: When the bicep muscle (a flexor) contracts and the tricep muscle relaxes, the arm bends.
When the tricep muscle (an extensor) contracts and the bicep muscle relaxes, the arm straightens.
Voluntary Muscle Contractions
Skeletal SystemInternal body framework = skeletonStructures: bones, cartilage, ligaments, tendons
Functions: Supports the bodyProtects internal organsEnables movementStores calciumMakes blood cells
Bone Structure
Bones – cells and protein fibers supported by hard calcium
Cavities within bones contain soft bone marrow, which produces blood cells.
Joints
Joints – where bones are joined together
Tendons – connect muscle to bone
Ligaments – connect bone to bone
Cartilage – a protective cushion or covering
Integumentary System
Structures: skin and its structures (hair, nails, sweat glands, oil glands)
Functions: Serves as a barrier against infection,
injury, and UV radiation from the sun Helps to regulate body temperature
(by sweating or expanding blood vessels)
Removes waste (sweat)
Close-up of Integumentary System
Excretory System
Structures: kidneys, ureters, urinary bladder, urethra (other: skin, lungs)
Functions: Eliminates waste, especially
byproducts of metabolism Regulates (controls) the amount of
water in blood, which determines blood volume and pH
Blood enters kidneys, full of excess water and nitrogenous wastes.
Excess water & wastes filtered out by the kidneys, collected as urine.
Urine travels down the ureters, gets stored in the bladder, and is expelled from the body through the urethra.
Remember: liver also filtered blood, but it removed toxins, whereas the kidneys remove wastes & water
How do the kidneys work?
Lymphatic System
Structures: white blood cells, thymus, spleen, lymph nodes, lymph vessels
Functions: Helps protect the body from disease
Maintains fluid balance in blood
Spleen – filters old blood cells from blood, stores extra blood
Immune System: Non-specific Defenses
Function: fights off invading pathogens and prevents growth and spread of cancer
Non-specific Defenses: protect body from all pathogens. Skin: physical barrier Mucous membranes: protect
interior surfaces Cilia: line bronchi to “sweep”
mucus and pathogens out of lungs
Immune System: Specific Responses
Specific Responses: defend against one certain invader (pathogen) White blood cells recognize an
invader
Create antibodies, proteins which bind to pathogens & mark them for destruction
Endocrine System
Structures: ovaries (females), testes (males), pancreas, hypothalamus, glands (pituitary, pineal, thyroid, parathyroid, thymus, adrenal)
Function: Chemical communication &
control Hormones - chemicals that are
released into the blood and signal cells to take action Actions include growth,
development, metabolism, and reproduction
Reproductive System
Male Structures: testes, epididymis, vas deferens, urethra, penis
Female Structures: ovaries, fallopian tubes, uterus, vagina
Functions: Produces reproductive cells Males: produce and deliver
gametes (sperm) to females Females: produce gametes
(eggs), maintain an environment which can support a developing embryo