Post on 27-Dec-2015
I. Chapter 35-2 & 35-3: Nervous System
B. FUNCTION: Coordinates & controls body’s response to internal/external environment
A. STRUCTURES: Brain, spinal cord, nerves, sense organs, receptors
II. Nervous System – has 2 major divisions:
A.Central Nervous System (CNS)
• analyzes & interprets messages received from neurons
• Brain & spinal cord
1) Cerebrum – Largest, voluntary activities, senses, intelligence, learning & judgment. Consists of approx. 10 billion neurons!
a. Parts
B. Peripheral Nervous System (PNS)- has 2 parts
• nerves outside the brain and spinal cord.
•Send and receive messages with the CNS
2. Autonomic Nervous System - INVOLUNTARY
• Relays info from
CNS internal organs
• ex. Heart rate, breathing
-REFLEX ARC – rapid, involuntary muscle movement
• Involves only neurons & spinal cord
• Brain gets bypassed!!
III. Structure of a NEURON (nerve cell)
1. DENDRITES – 1st to receive impulse
3. NUCLEUS
2. CELL BODY -surrounds nucleus
4. AXON – carries impulse away from cell body
5. MYELIN SHEATH – insulates/ prevents loss of impulse
6. AXON TERMINAL – end of neuron
IV. Types of Neurons
A. SENSORY neuron – from body to CNS (sense stimuli)
B. INTERNEURONS –from CNS to motor neurons(connect)
C. MOTOR neuron – from CNS to muscle/gland (move)
V. Neuron Organization
A. Neurons don’t touch!
C. SYNAPSE = space between 2 neurons
B. IMPULSE = electrochemical messages
Receptors and Sense OrgansReceptors and Sense Organs Sensory receptors are neurons that are specialized
to detect a stimulus.
They are found in HIGH concentration in the sense organs (eyes, ears, nose, mouth & skin).
They are found in LOW concentration throughout the rest of the body.
TypesTypes of Sensory Receptors
1. Mechanoreceptors: Respond to movement, pressure, tension
2. Photoreceptors: Respond to variations in light
3. Chemoreceptor: Respond to chemicals
4. Thermoreceptors: Respond to changes in temperature
5. Nociceptors: Respond to tissue damage &pain
b. Increase the speed of messages being sent
- Feeling of energy and wellness
c. After effect wears off fatigue & depression
2. Depressantsa. Alcohol, Barbiturates,
muscle relaxers, sleeping pills
b. Slows down messages
- Feeling of being relaxed, calm, sleepy
Section 36-3: I. Integumentary System (Skin)
A. Includes skin, hair & nails
B. Skin is largest organ of human body
C. Functions of the Skin:
1. Regulate body temperature
a. Blood vessels• When hot, vessels dilate & release heat
2. Senses – sensory neurons
3. Vitamins – when exposed to UV light, makes vitamin D
•detects hot/cold, pressure
helps absorb calcium
4. Remove Wastes • Sweat – releases excess water, salts & urea
5. Protection from…• Physical & chemical damage• Disease (1st line of defense)
D. 3 Layers of Skin: 1.Epidermis – outermost layer made of dead cells & constantly replaced
a. Keratin – protein that…• makes nails• gives tough texture• “waterproof” quality
b. Melanin – pigment that…
• colors the skin• protects cells from sun damage• more sun exposure makes more melanin
2. Dermis – inner, thicker portion of skin
Contains:• Nerves • Blood vessels • Hair follicles (warmth & protects)• Sweat glands• Oil glands – soften skin
3. Subcutaneous Layer (Hypodermis)
• Mostly fat deposits• Absorb impact• Retain heat• Store food/ energy
E. How Cuts Heal 1) Blood clots & cut closes
2) New cells push damaged cells to surface
3) Scab forms & WBC fight wound infection
4) New cells fill in gap of scab
Ch. 39-1 & 39-2: I. Endocrine System
A. FUNCTION: Transmit chemical messages to control growth, development & metabolism
B. Hormones & Glands1. Hormone = secreted chemical in blood stream or ducts that affects cells
Ex: Human growth hormone (HGH), insulin
2. Gland = organ that releases hormones into body
C. Compared to nervous system1. Message delivered throughout the body
2. Body’s response is slower than nerve impulse
1) EXOCRINE gland – secrete substance through ducts (Ex: sweat, tears)
D. Two Gland Types:
2) ENDOCRINE gland – secretes hormones into bloodstream
E. Endocrine Glands:1. Pituitary gland (in brain)
•regulates other glands
• most important (master gland)
2. Thyroid (in neck)• makes thyroxine; regulates metabolism
3. Adrenal glands (above each kidney)
• makes epinephrine (adrenaline) ; response to stress (fight or flight)
4. Pancreas • makes insulin; regulates glucose levels
Ex. Thyroid thyroxineThyroid gland controlled by hypothalamus & pituitary gland
Hypothalamus sense low levels of thyroxine in blood & sends a message to pituitary releases hormone
Pituitary signals the thyroid to produce & release thyroxine
Thyroxine sent to cells to speed metabolism