Transcript III. NEURAL SIGNALING, cont

UNIT IX – INTRODUCTION TO ANIMAL
PHYSIOLOGY
• Hillis – Ch 23, 29, 30, 34, 36
• Dual Campbell – Ch 27, 32,
37, 38, 39
• Baby Campbell – Ch 18, 20,
26, 28, 30
• Big Campbell – Ch 32, 40, 45,
48, 49, 50
I. ANIMAL PHYLOGENY
I. ANIMAL PHYLOGENY, cont
I. ANIMAL PHYLOGENY, cont
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•
Shared Characteristics
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 Most have
 Extracellular Matrix
o
 Regulatory Genes for Embryonic Development
o
Classification based on …
1.
Presence or absence of true tissues
2.
Symmetry
3.
Development of germ layers
4.
Presence of body cavity
5.
Embryonic development
I. ANIMAL PHYLOGENY, cont
1.
Tissues
•
Metazoa (Parazoa)
•
2.
Eumetazoa
Symmetry
• Asymmetry
• Radial
• Bilateral
I. ANIMAL PHYLOGENY, cont
3. Development of Germ Layers
•
Form various tissues & organs
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•
Diploblastic Organisms
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• Most animals are triploblastic
I. ANIMAL PHYLOGENY, cont
4.
Presence of Body Cavity
• Only applies to triploblasts
• Acoelomates
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•
Pseudocoelomates
 “_____________” body cavity
 Not lined with _____________
• Coelomates

I. ANIMAL PHYLOGENY, cont
5. Embryonic Development
• Applies to organisms with
bilateral symmetry, primarily
coelomates
• Protostomes
• Deuterostomes
I. ANIMAL PHYLOGENY, cont
• Recent Changes in Animal Phylogeny
 Based on molecular data including Hox genes, DNA sequences for rRNA,
mDNA
 In current classification, bilaterians are subdivided into 3 groups
 Deuterostomes
 Ecdysozoans
 Lophotrochozoans
I. ANIMAL PHYLOGENY, cont
II. PHYSIOLOGICAL REGULATION
• Importance of Feedback Control
o Cell Signaling
o Regulator
o Conformer
• Homeostasis
o Negative Feedback
II. PHYSIOLOGICAL REGULATION, cont
• Positive Feedback
II. PHYSIOLOGICAL REGULATION, cont
Thermoregulation
• Ectothermic
 Internal temperature determined by
environment
• Endothermic
 High metabolic rate generates high
body heat
III. PHYSIOLOGICAL REGULATION, cont
Thermoregulation, cont
•
Metabolism
 Sum of all energy-requiring biochemical
reactions
 Energy measured in Joules, calories, or
kilocalories (Calories)
 Metabolic rate may be determined by
 Monitoring rate of heat loss
 Measuring amount of O2 consumed
or CO2 produced
• Q10
 Used to show relationship between
temperature and biological
reaction/process
 Q10 = RT / RT-10
 Typical Q10 Range = 2 - 3
III. PHYSIOLOGICAL REGULATION, cont
Thermoregulation
II. PHYSIOLOGICAL REGULATION, cont
Thermoregulation
• Adaptations
 Torpor - Low activity; decrease in
metabolic rate
 Hibernation
 Estivation
 Brown Fat
 Insulation
 Behavioral Responses
 Countercurrent Heat Exchangers
III. PHYSIOLOGICAL REGULATION, cont
Thermoregulation
• Human Thermoregulation
III. INTRODUCTION TO HUMAN PHYSIOLOGY
• Four Types of Tissue
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


III. INTRO TO HUMAN PHYSIOLOGY, cont
• Epithelial Tissue
 Covers body and lines organs
and cavities
 Forms glands
 May secrete mucus, be
ciliated
 Held together by tight
junctions
 Basement membrane
o Anchors one side of
epithelium to tissues
beneath
o Extracellular matrix made
up of protein,
polysaccharides
 Classified according to the
number of layers of cells and
the shape of the cells
III. INTRO TO HUMAN PHYSIOLOGY, cont
• Connective Tissue
 Bind and support other tissues
 Consists of cells loosely organized in an extracellular matrix
 Matrix is produced and secreted by cells
III. INTRO TO HUMAN PHYSIOLOGY, cont
• Nerve Tissue
 Senses stimuli and transmits signals from 1 part of the animal to another
 Two main types of cells
 Neuron
 Glia
III. INTRO TO HUMAN PHYSIOLOGY, cont
• Muscle Tissue
 Capable of contracting
when stimulated by nerve
impulses
 3 Types of Muscle Tissue
III. INTRO TO HUMAN PHYSIOLOGY, cont
NERVOUS SYSTEM
Hillis pp.673-693, 713-722
Phineas Gage
1823 - 1860
Dr. Rufus Weaver
& Harriet Cole
I. HUMAN NERVOUS SYSTEM
II. CELLS OF THE NERVOUS SYSTEM
• Glia
o Support cells
o Mostly non-conducting cells
that provide support,
insulation, protection
o Types
 Astrocytes
 Microglia
 Oligodendrocytes /
Schwann Cells
II. CELLS OF THE NERVOUS SYSTEM, cont
• Neuron
o Basic unit of function
o Three types
 Afferent Neurons
 Sensory neurons
 Convey signals from sensory
receptors to CNS
Efferent Neurons
 Motor neurons
 Convey signals from CNS
to effector cells (glands or
muscles)
 Interneurons
 Integrate, interpret data;
relay signals to other
neurons
II. CELLS OF THE NERVOUS SYSTEM, cont
III. NEURAL SIGNALING
• A Closer Look at a
Neuron
 Dendrite
 Cell Body
 Axon
o Myelin Sheath
o Nodes of
Ranvier
o Saltatory
Conduction
 Axon (Synaptic)
Terminal
• Synapse
III. NEURAL SIGNALING, cont
• Membrane Potential
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Due to selective permeability of plasma membrane
High concentration of Na + outside, K+ inside
Maintained by Na/K Pump, channels
Net negative charge of about -70mV
Known as resting potential
III. NEURAL SIGNALING, cont
•
Gated Ion Channels
 Channels that open/close
in response to a stimulus
 Seen in neurons, muscle
cells
 Hyperpolarization
o Opening of
 Depolarization
o Opening of
 Action Potential
III. NEURAL SIGNALING, cont
•
Threshold
 Stimulus strong enough to
increase voltage to ~ -50mV
 Action Potential triggered
• Sequence of Events
 Resting State
 Stimulus
 Depolarization
Na+ channels open
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
III. NEURAL SIGNALING, cont
 Repolarization
Na+ channels close; K+ channels
open slowly
K+ ions leave
cell returns to negative
 Hyperpolarization
Also known as undershoot
K+ gates close very slowly → K+
ions continue flowing out of cell
Results in brief period where cell is
more negative than resting state
Known as refractory period;
neuron is insensitive to
depolarization until resting
potential is restored
Resting potential restored by Na-K
Pump
III. NEURAL SIGNALING, cont
•
•
•
•
Movement of the action potential is self-propagating
Regeneration of “new” action potentials only after refractory period
Forward direction only
Speed of action potential related to
 Axon diameter
 Saltatory conduction
III. NEURAL SIGNALING, cont
• Chemical Synapses
 Impulses are transmitted across
the synaptic cleft by chemicals
known as neurotransmitters
 When action potential reaches
axon terminal,
o Depolarization triggers
opening of Ca2+ gated
channels
o Ca2+ ions diffuse into axon
o Results in fusion of vesicles
containing neurotransmitters
with axon terminal
membrane
o Neurotransmitters “spit out”;
diffuse across synapse
III. NEURAL SIGNALING, cont
 Neurotransmitters received by protein receptors on post-synaptic cell. Categorized
based on effect:
Excitatory Post-Synaptic Potentials (EPSPs)
Inhibitory Post-Synaptic Potentials (IPSPs)
III. NEURAL SIGNALING, cont
III. NEURAL SIGNALING, cont
Nerve Impulse Transmission - A Review
IV. ORGANIZATION OF HUMAN
NERVOUS SYSTEM
IV. ORGANIZATION, cont
Reflex Arc
V. CENTRAL NERVOUS SYSTEM
• Consists of
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
V. CNS, cont
Human Brain
•
Forebrain
 Cerebrum
 Cerebral Cortex
 Corpus Callosum
 Thalamus
 Hypothalamus
•
Midbrain – Receives & transmits sensory
info to forebrain
•
Hindbrain
 Cerebellum
 Pons
 Medulla oblongata
V. CNS, cont
A Closer Look at the Cerebral Cortex
V. CNS, cont
The Limbic System
VI. PERIPHERAL NERVOUS SYSTEM
VI. PNS, cont
•
Nerves
 Bundles of
sensory &
motor
neurons
 12 pairs of
cranial
nerves
 31 pairs of
spinal
nerves
VII. SKELETAL MUSCLE FUNCTION
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•
Muscle tissue → muscle fibers →
myofibrils → myofilaments
Two types of myofilaments
 Thin Filaments
 Two strands of actin
 Thick filament
 Myosin
Sarcomeres
•
Sliding Filament Model
•
VII. SKELETAL MUSCLE FUNCTION, cont
•
Sliding Filament Model
 Myosin binds ATP; hydrolyzed to ADP + Pi
 Myosin head changes shape; termed high energy configuration
 Myosin head binds to specific site on actin; forms a cross bridge
 ADP and Pi released; myosin relaxes to low energy configuration
 Causes actin to slide toward center of sarcomere
 Binding of new ATP releases myosin head
VII. SKELETAL MUSCLE FUNCTION, cont
• Regulation
 Due to interactions of calcium,
tropomyosin
 Relaxation
Tropomyosin blocks myosin
binding sites on actin
Held in place by troponin
complex
 Contraction
When Ca is available, it
binds to troponin complex
Tropomyosin shifts
Myosin binding sites are
exposed
Muscle can contract
VII. SKELETAL MUSCLE FUNCTION, cont
Summary
VII. SKELETAL MUSCLE FUNCTION, cont
• Fast-twitch Fibers
• Slow-twitch Fibers
• Energy Availability Adaptations
 Creatine Phosphate
 Myoglobin
ENDOCRINE SYSTEM
Hillis pp.603-618
I. INTRODUCTION TO ENDOCRINE FUNCTION
•
Glands may be
 Exocrine
 Endocrine
Target
I. ENDOCRINE FUNCTION, cont
Regulation
II. TYPES OF HORMONES
Water-Soluble Hormones
•
•
Hydrophilic
Most common
•
Signaling involves three key events:
 Reception
 Signal Transduction
 Response
II. TYPES OF HORMONES, cont
Steroids
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•
•
Derived from cholesterol
Include sex hormones
Small, nonpolar hormones that
diffuse through cell membrane
III. ENDOCRINE SYSTEM OVERVIEW
III. GLANDS OF THE ENDOCRINE SYSTEM
Posterior Pituitary Gland
• Oxytocin
• Antidiuretic Hormone (ADH)
IV. GLANDS OF THE ENDOCRINE SYSTEM
Anterior Pituitary Gland
• Tropic Hormones
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FSH
LH
ACTH
TSH
IV. GLANDS OF THE ENDOCRINE SYSTEM
Anterior Pituitary Gland, cont
• Growth Hormone
 Gigantism
 Dwarfism/acromegaly
III. ENDOCRINE SYSTEM GLANDS, cont
•
Pineal Gland
 Melatonin
•
Thyroid Gland
 Calcitonin
 Thyroxine
•
Parathyroid Gland:
 PTH
III. ENDOCRINE SYSTEM GLANDS, cont
Pancreas
Pancreas
•
•
Islets of Langerhans
produce
 Alpha cells: glucagon~
raises blood glucose
levels
 Beta cells: insulin~
lowers blood glucose
levels
Type I Diabetes mellitus
 Insulin-dependent
 Autoimmune disorder
•
Type II Diabetes mellitus
(insipidus)
 Non-insulin-dependent
 Reduced responsiveness
in insulin targets)
III. ENDOCRINE SYSTEM GLANDS, cont
Adrenal Gland
•
Adrenal Medulla (catecholamines):
 Epinephrine/Norepinephrine
•
Adrenal Cortex (corticosteroids):
 Cortisol → Raises blood glucose
 Aldosterone → Stimulates kidneys to ↑ reabsorption of Na+, water follows
III. ENDOCRINE SYSTEM GLANDS, cont
Testes
III. ENDOCRINE SYSTEM GLANDS, cont
Ovaries