Human Nervous System
- • Nervous system
- – System of
interconnected nerve cells (neurons)
- – Extends through
entire body
- – Central
nervous system (CNS)
- – Peripheral nervous
system (PNS)
- • Higher nervous
system functions (thought, language, learning)
- • Less complicated
integration (reflex)
- – Occurs in the
spinal cord
The Neuron
- • Dendrites – Long,
thin, highly branched extensions
- • Cell body –
Contains nucleus & cell organelles
- • Axon – Single long
extension of cell body
• Resting potential – Voltage between cell
interior & extracellular fluid
• Action potential generation
(nerve cell impulse) – Neuron responds to stimulus
The Synapse
- • Synapse –
Junction between neuron & another cell
- • Neurotransmitter
– Chemical messenger
- • Chemical synapses
– Slowest points in any nervous system pathway
The Human Nervous System
- • Peripheral nervous
system
- – Somatic NS
- • Voluntary
actions of body
- – Automatic NS
- • Involuntary
actions of body
-
Hormones
- • Cells of animals’
bodies communicate via chemical messengers – hormones
- • Hormones are
found in many organisms, such as other animals & fungi
- • Hormones are
regulated by feedback control mechanisms
- • Tissues in body
that produce & secrete hormones constitute endocrine system
The Hypothalamus
- • Hypothalamus
- – Separate from
parts of brain where higher thought originates
- – Small part of
total brain (~ 1/300 of total mass)
- – Is involved in
regulating many physiological processes
- – Is controlled by
feedback loops that regulate production & release of hormones
The Pituitary
- • Pituitary
- – Posterior (rear
part)
- • Antiduretic
hormone (ADH)
- • Oxytocin
- – Anterior
(forward part)
- • Releasing
hormones
- •
Release-inhibiting hormones
The Human Digestive System
- • Breaking down
& taking in food is accomplished by 4 processes in digestive system
- – Digestion
- – Secretion
- – Motility
- – Absorption
From the Mouth – Intestine
- • Mouth – where
process of digestion begins
- – Saliva, enzymes
- – Chewing
- • Esophagus – tube
leading from mouth to stomach
- – Epiglottis
- – Peristalsis
From the Mouth – Intestine
- • Stomach –
digestive system’s storage compartment
- – Protein digestion
begins in stomach
- • Intestine – where
the most of digestion & absorption of nutrients occur
- – Small intestine
- Final stages digestive process are carried out
- – Large intestine
- Role is to store fecal matter, absorb water from it.
Human Respiratory System
- • Respiratory
system brings oxygen-rich air in contact with moist surface &
needs 3 parts:
- – Diaphragm – a
pump for creating airflow
- – Lungs – large,
wet surface for gas exchange
- – Nose, mouth,
trachea & bronchi
- • Ventilation –
Movement of air between alveoli & environment
- • Gas exchange in
lungs – Respiratory system is designed to bring air in close proximity to
blood
- • From lungs,
oxygen-rich blood is carried to all cells of body
Human Circulatory System
- • Cardiovascular
system
- – Body’s transport
system (nutrients, gas, hormones, ions, sugars, antibodies)
- • Composed of
heart & all blood vessels
- – Heart
- • 4-chambered pump
that moves blood
- – Blood vessels
include arteries, veins, capillaries
• Human heart
- – Has 4 chambers –
2 atria & 2 ventricles
- • Moves entire
blood content (about 5 liters) for the whole life
· •
Heartbeat
- – Rhythmic
contraction of muscle cells composing heart chamber walls
- • Electrical
component
- • Mechanical
component
- Circulatory System:
Vessels
- • Arteries
- – Thick-walled,
elastic vessels
- – Carry blood
from heart to tissues
- • Arterioles
- – Arteries branch
into these smaller-diameter vessels
- • Capillaries
- – Arterioles
branch many times leading to capillaries
- • Venules &
veins
- – Capillaries converge
to to form small veins (venules) which merge into larger & larger
veins
Human Urinary System
- • Homeostasis of
body fluids – A primary function of urinary system
- • It includes –
Kidneys, urinary bladder, & tubes that connect them to each other
& outside
- • Kidneys are
organs that
- – Clean blood of
metabolic wastes
- – Also maintain
water & salt balance
- Human Urinary
System
- • Each kidney is
connected to urinary bladder by thin tube called ureter
- • Bladder opens
to outside of body through a tube called urethra
- • Nephron –
kidney’s functional unit
-
- • Three renal
processes
- – Filtration
- – Reabsorption
- – Secretion
The Reproductive Male
- • Testes
- – Paired organs
that lie outside of male abdominal cavity in a sac called scrotum
- • Each testes
packed with highly coiled seminiferous tubules in which sperm are produced
- • From seminiferous
tubule sperm enters another coiled tube - epididymis
- • Testes lie in a
sac called scrotum
- – Packed with
highly coiled seminiferous tubules
- • From epididymis –
Sperm go into vas deferens (vasa deferentia, plural), a duct behind
bladder
- • During sexual
arousal
- – Sperm enter
urethra from vasa deferentia & are mixed with secretions of glands
- • Mixture of
sperm & glandular secretions is called semen
- • As sexual stimulation
intensifies
- – Semen is
ejected from urethra by rhythmic contractions (ejaculation)
- • Ejaculation
- – Part of total
sexual response called orgasm
The Reproductive Female
- • Ovaries – Where
eggs develop
- • Uterus or womb –
Embryo implants & develops during pregnancy
- • Oviducts or
fallopian tubes – Eggs travel from ovaries to uterus
- • Vagina
-
- • Menstrual cycle
- – Menstruation,
ovulation, endometrium, corpus luteum
- • Pregnancy
The Human Immune System
The First Line of Defense
• Body has defenses from disease-causing entities – immunity
• Immune system
- – Integrated
throughout the body
- • Lymphoid tissues
- – Play a role in
immunity
- – Diffused &
integrated into tissues of other systems
- • Lymphoid tissues:
- – Red bone marrow
- – Thymus gland
- – Lymph nodes
- – Spleen
Nonspecific
Responses
- The Second Line of
Defense
- – Involves
phagocytes (eating cells) of immune system
- • Also involves
chemicals
- – In addition to
phagocytic cells
- Nonspecific
Responses
- • All of these
second-line defenses
- – Cause infected
body region to become
- • Red
- • Hot
- • Tender
- • Swollen –
inflammation
The Third Line of Defense
- • Acquired immune
responses – Recognize familiar, repeat invaders
- • Antibodies –
- – Lymphocytes that
are distinguished from one another by specific kinds of protein embedded
in their cell membranes
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