Nervous, Integumentary & Endocrine Systems Ch. 35-2, 35-3, 36-3, 39-1 & 39-2.

Nervous, Integumentary &

Endocrine SystemsCh. 35-2, 35-3, 36-3,

39-1 & 39-2

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. Brain

• FUNCTION: Oversees daily operation of body & interprets info it receives

1) Cerebrum – Largest, voluntary activities, senses, intelligence, learning & judgment. Consists of approx. 10 billion neurons!

a. Parts

2) Cerebellum – 2nd largest. muscle coordination & balance

3) Brain stem – links the cerebrum w/ spinal cord. Breathing, swallowing controlled here

http://www.sciencebob.com/graphics/brain.jpg

http://schools.lwsd.org/Juanita/staff/kohlwes/Sensory.htm

2. Spinal Cord – links brain to body. Reflexes are processed here

Brain Spinal cord Body

B. Peripheral Nervous System (PNS)- has 2 parts

• nerves outside the brain and spinal cord.

•Send and receive messages with the CNS

1. Somatic Nervous System - VOLUNTARY

• Relays info. from senses CNS muscles

•Ex. Reach for a book

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

http://shp.by.ru/spravka/neurosci/

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

Nervous system and drugs

1. Stimulants

a. Cocaine, nicotine, caffeine, amphetamines

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

c. Can slow down the system too much body stops breathing

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

• When cold, vessels constrict & heat is conserved

b. Sweat – released by glands to cool body

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

F. Feedback Mechanism

1. adjusts to regulate amount hormone levels

2. maintains HOMEOSTASIS

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

Low Hormone Level

Increase Hormone

Production

High Hormone Level

Decrease Hormone

Production