Human Systems
Chapters 27-33
Body Terms
• Anatomy: the study of the structure of an
organism and its parts
• Physiology: study of the function of structures
• Cell --> Tissue --> Organ --> Organ System --
> Organism
Tissues
• Epithelial
– Closely packed cells that
cover surface of body and form
lining of organs
• Connective
– Hold together and support
other tissues
– Cushion, insulate, and connect organs
• Nervous
– Forms the communication system
– neuron: nerve cell; transmits signals
• Muscle
– skeletal muscle (voluntary); cardiac muscles (involuntary);
smooth muscles (involuntary)
Integumentary System
• The body’s outer
covering
– Separates the body
from the external
environment
Skin
• 2 mm thick
• Epidermis: outer layer
– Mostly dead cells
– Bottom layer produces
melanin
• Dermis: second layer
– Connective tissue
– Hair follicles, sweat
glands, muscles, nerves,
blood vessels
• Hypodermis: below
dermis
– Adipose tissue
Hair and Nails
• Hair
– covers body
– Made of keratin
– Formed in hair
follicles
• Nails
– Keratin
– Grow by cells
underneath pushing
up
Homeostasis
• Homeostasis: internal stability maintained by
your body
• Skin
– Barrier against dirt and microbes
– Insulation
– Water (sweat)
• Hair
– Protects from UV rays
– Insulation
– Barrier against dirt and microbes
Skeletal and Muscular System
Skeletal System
• Maintain body
shape
• Protect organs
• vertebrae: column
of small bones that
form the backbone
– Cartilage in between
– Connective tissue
Bones
• Made of connective tissue
• Bone matrix: surrounds bone cells
– Fibers
• Collagen (protein)
• Calcium and phosphate
• Fibrous connective tissue
– Forms new bone
• Cartilage (at ends)
– Cushions and prevents rubbing
• Marrow
– Yellow: stored fat and energy reserve
– Red: blood cells
Joints
• Joint: area where
one bone meets
another
– Immovable joints
– Movable joints
• Held together by
ligaments
Movable Joints
• Pivot Joint
– Rotate around another
bone
– Skull
• Ball-and-socket
– Rotate and move back
and forth
– shoulder
• Gliding Joint
– Slide over each other
– wrist
• Hinge Joint
– Back and forth
– knee
Bone Disorders
• Osteoporosis
– Deterioration of bone
structure
– Lack of calcium
• Arthritis
– Inflammation of joints
Muscular System
• 600 + muscles
• Connective, nervous
and muscle tissue
• Tendon: connects
bone to muscle
• Work in pairs
Muscle Types
• Cardiac Muscle
– Heart
– Involuntary
• Smooth Muscle
– Lining of organs
– Stomach, uterus, blood
vessels
– Involuntary
• Skeletal Muscle
– Movement
– Voluntary
Muscle Structure
• Muscle =
– bundles of parallel
muscle fibers
– nerves
– blood cells
• muscle fiber: single
long cylindrical
muscle cell that
contains many
nuclei
Muscle Fiber
• Myofibrils: smaller
bundles
– Striated
– Sarcomere: unit of action
• actin: (protein) thin
filaments
• myosin: (protein) thick
with myosin heads
• Contraction
– Myosin heads bind to
actin filaments
– Heads bend and pull
Muscle Contraction – ATP binds to myosin
head to release it
Nervous System
• Central nervous system
(CNS): brain and spinal
cord
– Main info processing
center
• Peripheral nervous
system (PNS): other
nervous tissue
– Delivers info to and from
CNS
– Nerve: one or more
bundles of neuron fibers
surrounded by
connective tissue
Functions
1. Sensory Input
– stimulus: environmental change
(ex color)
• Received by PNS
– sensory neurons: carry info about
stimuli
• Some sense pain
– sensory receptors: receive stimuli
2. Integration
• CNS interprets info
• interneurons
3. Motor Output
• CNS orders reponse
• motor neurons: carry signals
away
Neurons
• Neuron: specialized cell in
brain
• dendrite: receive signals
• axon: carries electrical
impulses
• myelin sheath: axon’s
insulation
• node: uninsulated part of
axon where signal travels
• axon terminal: info is
transmitted to next neuron
Nerve Signals
• resting potential:
voltage across the
membrane of a resting
neuron
• depolarization: voltage
changes
• action potential: start of
a nerve signal
• 5 meters per second
Synapses
• synapse: junction between
terminals and another neuron
– Electrical : heart and digestive
organs
– Chemical: brain
• Synaptic cleft: space where
chemical signal is transmitted
• Neurotransmitter: chemical
signal
– Nitrogen-containing organic
compounds
– Contained in vesicles
– Serotonin, epinephrine,
dopamine, etc
Somatic Nervous System
• Motor neurons carry signals from CNS to skeletal
muscles
• Voluntary
• Some are reflexes
Autonomic Nervous System
• Carries signals to
organs
• Mostly involuntary
• Sympathetic and
parasympathetic
– Opposing effects
Sympathetic and
Parasympathetic Divisions
• Sympathetic Division
– Increases general level
of activity and energy
– Prepares for intense
activities
– “fight-or-flight”
• Parasympathetic
– Calms body
– Returns to normal
function
The Brain
• 100 billion neurons
• Cerebrum: largest part
of brain
• corpus callosum:
connects 2
hemispheres
• cerebral cortex: outer
region (5mm)
– 40% of mass
– Divided into lobes
Cerebral Cortex
• Frontal = motor,
speech
• Parietal= sensory,
speech, taste,
reading
• Occipital= vision
• Temporal= hearing
& smell
Brain
• cerebellum: coordination
center for movement and
position of parts
• brainstem: lower section;
filters info
– Regulates sleep, breathing,
coordination
– Medulla oblongata, pons,
midbrain
• thalamus: sorts info
• hypothalamus: regulate
temp, blood pressure,
hunger, thirst
– Endocrine system
Memory
• Short-term to long-
term
• Limbic system:
connection between
memory, emotions,
and senses
– Amygdala,
hippocampus, parts
of cortex, thalamus
and hypothalamus
Sensory Receptors
• Pain receptors
– sensed by free nerve
endings
• Thermoreceptors: skin
and internal organs
– temperature
• Mechanoreceptors
– Touch, pressure, stretch,
motion
• Chemoreceptors
– Nose and taste buds
• Photoreceptors
– eyes
Vision
• cornea: helps focus
light; secretes mucus
• iris: coloring and blood
vessels
• pupil: controls amount
of light (aperture)
• lens: focuses images
onto retina (lens)
• retina: inner surface
(film)
– Cones: blue, red, green
– Rods: light sensitive
Hearing and Balance
• Outer Ear
– auditory canal: tunnel-like opening
– Collects sound waves
– eardrum: tissue that separates outer
from middle
• Vibrations
• Middle Ear
– Hammer, anvil, and stirrup receive
vibrations and pass through oval
windows
– auditory tube: equalizes pressure
• Inner Ear
– cochlea: fluid-filled channel •Helps maintain balance
• Small hairs inside initiate action
potentials •fluid
Smell and Taste
• Smell
– Chemoreceptors
have cilia with mucus
• Trigger action
potentials
• Taste
– 3,000 taste buds
• With specialized cells
– Sweet, bitter, salty,
sour
Digestion
4 Stages of Food
Processing
• Ingestion
– Act of eating/drinking
• Digestion
– Breaking down into
smaller molecules
• Absorption
– Absorb and transport
• Elimination
Digestive Organs
• Alimentary canal:
tube where
digestion occurs
• Accessory glands
and organs
– Salivary glands,
pancreas, liver, gall
bladder
Mouth and Pharynx
• Mouth
– Chemical and
mechanical digestion
– saliva: contains
amylase to break
down starch
• Pharynx
– bolus: chewed
clump of food
Esophagus and Stomach
• Esophagus ~ 7 sec
– Muscle-encased tube
– peristalsis: muscle
contractions that push
down food
• Stomach ~4 hrs
– 2 L of food
– Gastric juice: mucus,
HCl, enzymes
– chyme: acidic
liquid/paste
– Pyloric sphincter:
regulates flow
Small Intestine
• ~5.5hrs
– 6m/ 20 feet
• Digestion
– Duodenum
• Liver: produces bile
(separates fat)
• Bile stored in gallbladder
• Pancreas: pancreatic juice
• Neutralizes acid chyme
and hydrolizes carbs,
proteins, lipids
• Absorption
– Villi: finger-like projections
• Microvilli
• Capillaries and lymph
vessel
Large Intestine (Colon)
• ~ 18 hrs
• Undigested material
passes through
• Reabsorb water
– Reclaim ~ 90%
• Vitamin K and B vit
• Remainder as feces
Nutrition
• Carbohydrates
– Primary fuel
• Fats
– Build cellular membranes
• Proteins
– Make enzymes and other
proteins; fuel
• Vitamins
– Various; aid enzymes
• Minerals
– various
• Water
Excretory Questions
1. Name the 2 main organs of the
excretory system.
2. What is the general function of this
system?
Excretory System
• Kidneys: excrete waste
products and regulate
water and salt balance
– urine: water, urea, and
wastes
– urea: ammonia and CO2
produced in liver
– ureter: tube that
connects kidney to
bladder
• urinary bladder: stores
urine
• urethra: carries out
urine
Kidney Structure
• Renal cortex (outer)
and renal
medulla(inner)
• nephrons: filtering
tubule
– One tubule and
blood vessels
– 1 million
Processing
• Blood is processed and urine
excreted
1. Filtration
• glomerulus: ball of capillaries
• Filtrate forced out into Bowman’s
capsule
• Water, urea, glucose, salts,
amino acids
2. Reabsorption
• Water, nutrients, and salts
reabsorbed
3. Secretion
• Remove substances from blood
into filtrate
4. Excretion: 1.5 L per day
Circulatory System
• Delivers nutrients and
oxygen
• Transports hormones
• Carries waste away
• Repairs tissues and
fights infection
• Three Components
– Blood
– Heart
– Blood vessels
Blood Vessels
• Capillaries
– Microscopic blood
vessels; one cell thick
• Arteries
– Thick-walled vessels
– Take blood to capillaries
– Smooth muscle and
connective tissue
• Veins
– Blood returns from
capillaries
– Very little pressure
Chemical Exchange
• Substances in
capillaries go
through interstitial
fluid before tissues
• Oxygen and CO2
diffuse across
membrane
Blood Flow
• 5 L of blood; 1 min
• pulmonary circuit:
carries oxygen-depleted
blood to lungs and back
to heart
– Right side
• systemic circuit: carries
oxygen-rich blood to
body and back to heart
– Left Side
– aorta: artery that
supplies oxygen to body
The Heart
• 4 Chambers
– Right parts are on left
side of pictures/ right side
of body
• Atria: receives
• Ventricles: pump out
• Valves: prevent
backflow
• pacemaker: sets
contraction rate
– Wall of right atrium
– Electrical impulses
– AV node: impulses to
contract ventricles
Blood
• Plasma: liquid connective
tissue
– 55% of blood
– 90% water
• Salts, proteins, other
• Red Blood Cells (erythrocytes)
– 25 trillion
– Carry oxygen
– Hemoglobin: protein that
stores oxygen for delivery
• White Blood Cells:(leukocytes)
– Fight infection and prevent
cancer
• Platelets: clotting
Circulatory and Respiratory
Systems
Respiratory System
• Mouth, nose, pharynx,
larynx, trachea, lungs
• pharynx: throat;
trachea and esophagus
meet
• epiglottis: covers
trachea
• larynx: voice box
• trachea: windpipe
• bronchi: connect
trachea to lungs
Lungs
• Exchange oxygen
and CO2
• bronchioles:
branching of bronchi
• alveoli: clusters of
air sacs
– Oxygen dissolves in
film of moisture
Breathing
• diaphragm: sheet of
muscle at bottom of
chest cavity
• CO2 levels regulate
breathing
• Controlled by medulla
oblongata
Lymphatic System
• Collects and returns
interstitial fluid to
circulatory system
• Lymph: fluid in
lymphatic vessels
• Lymph nodes: help
defend against
infection
– Contain cells that
destroy bacteria and
viruses
Immune System
• pathogens: disease
causing organisms
or viruses
• infectious disease
– Common cold
– Lyme disease
– HIV
– Salmonella
– Athlete’s Foot
Defense
1. Barriers
• Nonspecific
• Skin
• Sweat and oil
2. Internal Nonspecific
• White blood cells
• Inflammation
• Proteins
3. Targeted
• Immune system
• Specific
Internal Nonspecific
• White Blood Cells (leukocytes)
– Phagocytosis
• Macrophages
– Interstitial fluid
• Neutrophils
– Smaller and numerous
– Release bleach-like chemical
– Identify proteins and carb
– Natural Killer (NK)
• Insert chemicals into viruses
• Inflammatory Response
– Mast cells release histamine
• Specialized Proteins
– Interferon: protein produced by cells
that interfere with viral reproduction
Recognizing
Invaders
• Immunity
– Resistance
• Antigen: molecule that
provokes an immune
response
– “antibody-generating”
– Found on surface of viruses,
bacteria, fungi, etc
– Markers; knobs on surface
• Antibodies: proteins that
attach to antigens
– Bind to antigen
– Bind to toxins
– Cause pathogens to clump
Lymphocytes
• Recognize specific invaders
– White blood cells
• Bone marrow
• B cells
– Develop and mature in marrow
– Produce memory cells or
plasma cells
• T cells
– Mature in thymus
– Helper or Killer cells
Nobel Prize Site
B Cells
– 100 million surfaces
– Mostly bacteria and
viruses
– Plasma cell: secretes
antibodies
– Humoral immunity:
from B cells
T Cells
• Cell-mediated
Immunity: Directly
attack infected host cell
• Receptors for antigens;
activates
• Cytotoxic T cells:
developed from clones
– Secrete perforin
• Kill cancer cells
– Weaker immune= cancer
• Helper T Cells:
recognize macrophages
– Activate cytoxic T cells
and B cells
The Man Who Couldn’t Get
AIDS
Vaccine
Dose of a pathogen
that has been
deactivated
• Active Immunity
– Body produces
antibodies
• Passive Immunity
– Receive antibodies
– Fetuses
Immune Disorders
• Allergy: abnormal over-
sensitivity to a non-
harmful antigen
(allergen)
– Pollen, dust, cat dander/
saliva
– Anaphylactic shock
• Autoimmune disease:
immune system attacks
own body cells
– MS, Rheumatoid arthritis
• Transplants
– cyclosporine
Endocrine System
• Hormones that have various
functions
• Steroid
– Sex hormones
– Some adrenal
– Moves across membrane
– Binds w ith receptor and “turns on”
genes for proteins
• Nonsteroid
– Bind to receptors at membrane
– Activates proteins
Hormones
Female Reproductive System
• Ovaries: produce egg cells
and female hormones
• Follicle: surrounds the
developing egg cell;
provides nourishment
• Oviduct(fallopian tube):
passageway to uterus
• Uterus: muscular organ
that protects developing
baby
• Cervix: neck of uterus;
connection to vagina
• Vagina: birth canal;
receives penis during
intercourse
Male Reproductive System
• Testes: development of
sperm and testosterone
• Scrotum: sac-like
structure that holds the
testes
• Epididymis: coiled tube
where sperm mature
• Semen: sperm and
other fluids
• Vas deferens: tubes
that transport semen to
urethra