Download Word Notes - Eric Hamber Secondary

N1. CENTRAL AND PERIPHERAL SYSTEMS
Central Nervous System (CNS):
- the brain and spinal cord in vertebrate animals
- protected by bone (skull and vertebrae)
- information processing
Peripheral Nervous System:
- nerves and ganglia that lie outside the central nervous system.
- projects towards and away from the central nervous system.
- carries impulses to and from the CNS
The peripheral system is divided into two groups of nerves
i) Somatic Nervous System:
- nerves that serve the musculoskeletal system (voluntary)
- nerves that serve the exterior sense organs
- gives you information about the external environment and allows you to
respond to it
ii) Autonomic Nervous System:
- Controls the internal organs automatically and without “awareness”
N2. SYMPATHETIC AND PARASYMPATHETIC SYSTEMS
1 Sympathetic System:
- Fight or flight
- dilates pupils, accelerates heartbeat and breathing rate, inhibits
digestive tract.
- Neurotransmitter is Noradrenalin
- Postganglionic is longer than preganglionic
- Come from middle of spinal cord
2 Parasympathetic System:
- Normal activity (opposite to Sympathetic system)
- maintains a “relaxed” body state
- Neurotransmitter is Acetylcholine
- Preganglionic is longer than post ganglionic
- Come from brain, lower part of spinal cord
Both Systems - function automatically, and activate internal organs
- have 2 motor nerves and 1 ganglia
- arise in different areas of the spinal cord and have quite different
structure and chemistry.
NERVOUS SYSTEM
OUTSIDE CNS
AWARE
UNAWARE (smooth muscle)
skeletal muscle
EMERGENCY
NORMAL
N3. ADRENAL GLAND
Adrenalin is a hormone produced by the medulla (inner layer) of the adrenal
glands (one on top of each kidney). It is responsible for maintaining the “fight or flight”
response. It is secreted in times of emergency or stress. Some affects of adrenalin are
- dilated pupils
- increased heart rate
- decreased blood flow and peristalsis in digestive tract
- increased blood flow to the CNS and skeletal muscles
It continues the affect of sympathetic nerve impulses, and is used as a neurotransmitter
substance in this system as well.
N4. BRAIN PARTS AND FUNCTIONS
Medulla Oblongata:
- Unconscious part
- Closest to the spinal cord
- centers for heartbeat, breathing
- vomiting, coughing, sneezing, hiccoughing, swallowing
- Control of internal organs
Cerebrum
- Responsible for consciousness
- largest portion of the brain (human)
- Outer layer: Cortex
Thalamus:
- “Gatekeeper” to cerebrum
- Last stop before the cerebrum
- Central relay station for sensory impulses (sorts out messages to cerebrum)
- Channels impulses to appropriate regions of the brain
Cerebellum:
- Resembles a butterfly
- 2nd largest portion of brain
- lets body have smooth and graceful motions (muscle coordination)
- maintains body position in space (proprioception)
- in charge of balance
Hypothalamus:
- Homeostasis
- hunger, sleep, thirst, body temperature, blood pressure
- link between nervous and endocrine systems (controls pituitary gland)
- Control of internal organs
Corpus Callosum:
- Horizontal tract, first nerve connection between L. & R. hemispheres
- Connects the two cerebral hemispheres to share information
Pituitary gland:
- link between nervous system and Endocrine system
Label the parts of the brain listed in sect. N4 of learning outcomes
N5. HYPOTHALAMUS / PITUITARY INTERACTION
The Hypothalamus is the part of the brain that is concerned with homeostasis
(maintaining a constant internal environment). The pituitary is a small gland (2 parts,
anterior and posterior lobes) that produces a large number of hormones, many of which
control the release of hormones from other glands in the body. For this reason it is often
called the “master gland”.
i) Posterior Pituitary
The posterior pituitary gland releases the
hormones that are actually made in the
Hypothalamus, but are stored in the Post.
Pit. The hormones are transferred and stored
in special hollow nerve fibres that run from
the hypothalamus to the post. pit.
eg. ADH and Oxytocin
ii) Anterior Pituitary
The anterior pituitary gland makes and
releases its own hormones. It is stimulated
to release its hormones by releasing
hormones from the hypothalamus. There is
a blood connection between the
hypothalamus and the ant. pit.
Hormones made in the Ant. Pit. include:
Growth hormone
Prolactin
FSH & LH
Thyroid Stimulating Hormone (TSH)
Adrenal Cortex Stimulating Hormone (ACTH)
Melatonin
The level of all the Pituitary hormones in the blood are monitored by the hypothalamus
and are controlled by a negative feedback system (except Oxytocin!), so the level of these
hormones remains relatively constant. The sex hormones FSH & LH vary in the female.
Assignment:
Read Ch. 17, P. 317-329, 334-337, Ch.20, 394-395 399
Test Yourself P.341, 1 – 19, 14
Study Questions
1. What are the three classes of nerve cells? How are they alike? How are they
different? (p. 318 – 319)
2. What is resting potential and how is it maintained? (p. 320)
3. What are the 2 phases of an action potential, and how are they brought about?
What is the refractory period and why is it important? (p. 320 -321)
4. Discuss the structures involved and steps that occur for an impulse to move from
1 nerve cell to another. (p. 322 – 323)
5. What is a Neurotransmitter substance and how do they work? How are they
destroyed? Name 2 important neurotransmitters. (p. 323)
6. Name the major parts of the brain and give a function for each. (p. 326 – 329)
7. Outline the path of a nerve impulse through a reflex arc. (p. 335)
8. What is the autonomic nervous system and what are its 2 main divisions? List
several differences between these two divisions. (p. 336 – 337)