Body Systems

Chapters 35-40

35.1 Organization of the Body

• Nervous System– Structures:

• Brain• Spinal cord• Peripheral nerves

– Function:• Recognizes &

responds to Δs in external & internal env.

35.1 Organization of the Body

• Integumentary System– Structures:

• Skin• Hair• Nails• Sweat & oil glands

– Function :• Barrier against infection• Protect against radiation• Regulate temp.

35.1 Organization of the Body

• Respiratory System– Structures:

• Nose• Pharynx• Larynx• Trachea• Bronchi• Bronchiols• Lungs

– Function:• Oxygen for respiration• Remove CO2

35.1 Organization of the Body

• Digestive System– Structures:

• Mouth• Pharynx• Esophagus• Stomach• Small & large intestines• rectum

– Function:• Break down food• Absorb nutrients• Eliminate waste

35.1 Organization of the Body

• Excretory System– Structures:

• Skin• Lungs• Kidneys• Ureters• Urinary bladder• Urethra

– Function:• Eliminate waste

35.1 Organization of the Body

• Skeletal System– Structures:

• Bones• Cartilage• Ligaments• Tendons

– Function:• Support body• Protect organs• Allow movement• Store minerals• Site of blood cell formation

35.1 Organization of the Body

• Muscular System– Structures:

• Skeletal muscle• Smooth muscle• Cardiac muscle

– Function:• Voluntary movement• Circulate blood• Move food through digestive system

35.1 Organization of the Body

• Circulatory System– Structures:

• Heart• Blood vessels• Blood

– Function:• Bring oxygen, nutrients, & information to

cells• Remove wastes• Regulate body temp.

35.1 Organization of the Body

• Endocrine System– Structures:

• Hypothalamus• Pituitary• Thyroid• Parathyroids• Adrenals• Pancreas• Ovaries/testes

– Function:• Control growth• Development• Metabolism• Maintain homeostasis

35.1 Organization of the Body

• Reproductive System– Structures:

• Testes• Epididymis• Vas deferens• Urethra• Penis• Ovaries• Fallopian tubes• Uterus• Vagina

– Function:• Reproductive cells• Nurtures/protects embryo

35.1 Organization of the Body

• Lymphatic/Immune System– Structures:

• White blood cells• Thymus• Spleen• Lymph nodes• Lymph vessels

– Function:• Protect from disease• Return fluid to circulatory system

Organization of the Body

• Multicellular organisms– Organ system: group of organs that

perform closely related functions–Organs: group of tissues that work

together to perform a complex function

–Tissues: group of similar cells that perform a single function

–Cells: basic unit of life

Goal of all body systems

• HOMEOSTASIS!– Balance w/in the body– Maintain a stable environment– Feedback inhibition

• Negative feedback• Shuts off original signal• Thermostat/hypothalamus example

Homeostasis & feedback inhibition

Room temp. increases Room temp. decreases

Senses temp change & turns on

heating system

Senses temp change & turns off

heating system

35.3 Central Nervous System

• Brain & spinal cord– Protected by skull & vertebrae– Meninges wrapped around 3x

• Note: meningitis

– Cerebrospinal fluid• Protects (shock absorber)• Nutrients & waste exchange

Parts of the Brain

• Cerebrum– Voluntary & conscious thought– Intelligence, learning, judgment

• Cerebellum– Coordinates movement– Balance

• Brain Stem– Connects brain to spinal cord

• Thalamus & Hypothalamus– Thalamus: gets sensory info & directs it– Hypothalamus: hunger, thirst, fatigue, anger,

temp

Reflexes

• Automatic response to stimuli• Allow body to respond w/o thought

– Esp important in danger situations

• Ex: blinking & sneezing

35.2 Nerves

• Communication network– Send & receive signals throughout body– Monitors & controls internal conditions – Respond to stimuli

• 3 types– Sensory

• organ spinal cord

– Motor• Brain muscles

– Interneurons• Sensory motor

Nerves

nucleuscell body

dendrites

axon

myelin sheath

nodes

axon terminals

• At rest– Na+ ions pumped out,

K+ ions pumped in but leak out

– Outside cell has a + charge

– Inside cell has a – charge

• Moving impulse– Stimuli– Reverses charge (+

inside, - outside)

The Impulse

• All or nothing– Threshold

• Below = no response• Above = response

• The Synapse– Where message transferred– neurotransmitters