Physiology Test 1

RBC are made of:
Iron, Vitamin B12 and Folic Acid. Lack of these could cause anemia, (pernicious anemia= Vit. B12 deficiency)
-plasma protein
-attracts water into the blood
-general carrier for steroid hormones in the blood
-ppl w/ kidney problems lack albumin causing edema
Plasma Proteins serve as:
-A reserve of amino acids for cell nutrition
-Maintain osmolarity
-Carrier for hormones and lipids
-Zymogens (inactive enzymes) that when activated cause blood to clot
- Buffer for pH
Blood Types A, B, O
AB: universal acceptor, no antibodies
B: antibodies against A
A: antibodies against B
O: antibodies against A, B, universal donor
WBC, multi-lobed nucleus and include:
Neutrophils, eosinophils and basophils
Two lobed, act against parasites
type of granulocyte
Tri-lobed granulocyte
antibacterial proteins, die on contact and form pus
first line of defense (50-70% of WBCs)
rare, IgE on surface, allergic reactions to release histamine and heparin, Is a granulocyte
A granulocytes
WBC, simple nucleus
Include Monocytes and Lymphocytes (T and B)
type of agranulocyte, digest bacteria and foreign substances (innate immunity) and present antigen to lymphocytes (acquired immunity)
T and B cells (differentiate into plasma cells which secrete antibodies)
acquired immunity
20-40% of WBCs in the body
Platelets release:
Serotonin (vasoconstrictor)
Thromboxane A2 (vasoconstrictor)
Thromboplastin (initiates blood clotting cascade)
Lymphoid progenitor cell (stem cell) produces:
Myeloid Progenitor cells (stem cell) produces:
Erythrocyte, Megakaryocyte (forms platelets), Eosinophil, Basophil, Neutrophil and Monocytes (forms macrophages)
Iron in the blood is needed to:
Bind oxygen (it's part of the Hb molecule in RBC)
Folic Acid:
essential for formation of DNA, Lack of this causes fewer RBCs
Vitamin B12
Essential for action of folic acid
requires intrinsic factor for absorption by GI tract
Lack of this causes pernicious anemia
Converts fibrinogen to fibrin, which makes fibers to add to the second clot (the "definitive clot")
Heparin inhibits blood clotting by:
inhibiting conversion of prothrombin to thrombin, which therefore prevents the activation of fibrinogen to fibrin
Prevents making prothrombin (which needs Vitamin K)
Plasmin works to:
dissolve clots. it's a protease released from inactive plasminogen.
4 Processes in Hemostasis:
1. Vasoconstriction: requires Calcium
2.Platelet Aggregation: release thromboxane A2, serotonin, thromboplastin and ADP
3.Blood coagulation: need Ca+ and Vit K (thrombin -> fibrin)
4.Clot Retraction: lysis of clot by plasmin
plasma without fibrinogen
the clotting of intravascular blood (within a blood vessel)
Hemostasis is the:
-Clotting of extravascular blood
-Includes vasoconstriction, platelet aggregation and blood coagulation.
-Dependent on Calcium and Vitamin K
Types of glial cells:
1. Schwann cells (PNS): isolate neuron from blood, forms myelinated cover around axon.
2. Oligodendrocyte (CNS): myelinated, forms around multiple axons
3. Astrocytes: isolates the blood stream from the neuron
Sodium Potassium ATPase function to:
- Sets up a small electrical gradient by pumping 2 Na+ out and 1 K into the cell (membrane potential at -70)
- establishes chemical concentration gradient
Graded Membrane potentials:
- are proportionate to stimulus strength
- decay over distance due to leakage of K+
- undergo temporal and spacial summation
-no refractory period
Voltage Gated Channels
- open at -50mV (due to graded membrane potentials)
- allow sodium in during depolarization (positive feedback)
- allows K out during re-polarization (causes hyperpolerization)
Axon hillock
Contains the highest # of voltage gated Na+ channels
Lowest threshold = initiates action potential
"integrative zone"
Parts of Neuron:
Dendrites:ligand gated ion channels= graded potential
Soma: cell body, graded potentials
Axon Hillock= voltage gated Na+ channels
Axon: voltage gated Na+ channels= action potential
Excitatory post synaptic potential (EPSP)
Excitatory event
Allows either Ca+ or Na+ into the cell to depolarize and continue to propagate a message through an action potential
Inhibitory post synaptic potential (IPSP)
Inhibitory, stops message
Allows Chloride inside the cell or K+ out to hyperpolarize the cell
Equilibrium Potential
when the chemical gradient and the electrical gradient are equal in magnitude but opposite in direction
-transmit signals over minutes to hours by activating second messenger cascades in the post-synaptic cell.
-Control/change excitability.
-include Serotonin, NO, ATP and NorEpi
Cerebral Cortex
- memory storehouse
- fine tunes the lower brain center functions
- essential for thought
Regions of Cerebral Cortex:
Frontal Lobe: complex thought
Parietal Lobe: somatosensory input
Occipital Lobe: sight
Temporal Lobe: speech, hearing, taste
Diencephalon includes:
1. Thalamus: relay and integration station for sensory input to cortex, key in generating arousal.
2. Hypothalamus: master gland for homeostatic regulation; coordinates neural and endocrine function
Basal ganglia function: (subcortical nuclei)
controls skeletal movement and posture
Parkinson's Disease is a malfunction of this
Limbic System
Learning, emotion, memory, appetite, sex, endocrine integration.
Coordinates movement and balance, "learned" movements, receives input from muscles, joints, viscera, eyes and ears. Malfunction= ataxia
Brain Stem includes:
Midbrain, Pons, Medulla oblongata
Relay station between spinal cord, forebrain and cerebellum.
Controls automatic functions (reticular formation) like breathing, BP and heart rate
Afferent Sensory Axon
Sent to the spinal cord through the dorsal root to the dorsal horn and up the spinal cord
Efferent Axon
Runs down the spine, out the ventral horn to the ventral root and connects in a spinal nerve
Spinal Cord Functions
Walking, govern withdrawal of limbs from painful stimuli, support posture, control GI movement, urinary excretion
Efferent Pathway types:
Somatic (motor)
Autonomic: Sympathetic (catabolic), Parasympathetic (anabolic) ..... or Enteric (acts independently in the gut)
Somatic (Part of Efferent Nervous System)
- Innervates skeletal muscle
- Neuron cell bodies lie in brain stem or ventral horn of the spinal cord.
- Axons leave CNS and pass without synapse to skeletal muscle
- Excitatory only
Autonomic (Part of Efferent Nervous System)
- Innervates smooth & cardiac muscle, glands and GI neurons.
- Has 2 neuron chain connected by a synapse between CNS and effector organ
- Sympathetic: leaves from from the thoracic/lumbar regions of spinal cord
- Parasympathetic: leaves from the brainstem and sacral portion of spinal cord.
Ganglia location of Sympathetic/Parasympathetic
Sympathetic: lie close to spinal cord and form the sympathetic trunk.
Parasympathetic ganglia: lie close or within the organs that the post-ganglionic neurons innervate
Nicotinic acetylcholine receptor
ligand gated ion channel which gates Na entry
located in CNS and at skeletal muscles synapses
Muscarinic acetylcholine receptor
located in PNS at parasympathetic synapses in heart
Growth Hormone Releasing Hormone
Peptide hormone released by Hypothalamus that effects the Anterior Pituitary --> releases GH
Anterior Pituitary releases
Causes liver to release IGF-1, which is responsible for growth of organs
Peptide secreted by the hypothalamus to inhibit GH release from the pituitary, IGF-1 increases the secretion of somatostatin. (negative feedback)
released by liver in response to GH from pituitary
increases growth of organs
Increases secretion of somatostatin (by hypothalamus) to inhibit GH
Set point
The operating range for a given variable.
Error is the deviation from the set point.
Rebound Effect
When the absence of a hormone for a period of time causes increased cell receptors, resulting in increased sensitivity to a signal.
Inhibits secretion of GH from the anterior pituitary
Two Point Discrimination
Depends on the size of the receptor field and the number of receptor fields/acuity.
Smaller and more fields you have, the higher two point discrimination.
Lateral Inhibition
When sensory units have overlapping receptor fields, the one with the highest firing frequency will inhibit firing of the lateral neurons (via inhibitory neurons) more than they will inhibit it.
Stimulus modality
Types of stimulus: cold and warm, sound, pressure, etc. There can be submodalities: bitter, sweet, salty
slowly adapting receptors
Maintains a persistent, slowly decaying receptor potential during a constant stimulus, initiating action potentials in afferent neurons for the duration of the stimulus
Precision with which we can locate and discern one stimulus from an adjacent stimulus.
The greater the convergence, the less the acuity
somatosensory cortex
Lies in the parietal lobe behind the central sulcus (which separates the parietal and frontal lobe)
Information from the outer part of the body are carried here including skin, skeletal muscle, tendons and joints
Polymodal neurons
Part of the nonspecific ascending pathways that are activated by several different types of sensory units.
Tells "something" is happening, non-specific.
Stimulus intensity can be increased by:
1. increasing firing frequency of action potentials
2. Recruitment: calling in nearby receptors to create a larger area of response.
Referred pain
Occurs because both visceral and somatic afferents often converge on the same neuron in the spinal cord.
Anterolateral pathway (somatosensory system)
1. First synapse is between the sensory receptor neuron and a second neuron located in the grey matter of the spinal cord.
2. Second neuron crosses to the opposite side and projects up the anterolateral column of the spinal cord to the thalamus. This info then gets taken to the somatosensory cortex
- Projects pain, temperature information, crude touch
Dorsal Column Pathway (somatosensory system)
1. Sensory neurons do not cross over to synapse immediately upon entering the spinal cord. They ascend to the brainstem (up the dorsal column) where the first synapse occurs
2. The second neuron then crosses over in the brain stem (in thalamus) as it ascends.
- Receptors for body movement, limb position, fine touch discrimination and pressure.
specialized nerve endings that respond to a number of different painful stimuli, like heart or tissue damage
respond to mechanical stimuli like pressure or stretch, touch, blood pressure, muscle tension
sense of smell and taste, ligand gated channels
Relay station for memory
Integrates with the rest of the limbic system including emotion, learning, appetite, etc.
Makes associations between memory and emotion
Somatic sensation
sensation from the skin, muscles, bones, tendons and joints
Initiated by a variety of sensory somatic receptors
- increased sensitivity to pain
- selective suppression of pain without effects on consciousness or other sensations
Sypathetic Nervous System (autonomic)
- Pre ganglion (CNS) and post Ganglion (PNS)
- post ganglion lie right outside CNS forming the sympathetic trunk
- uses acetalcholine for pre ganglion to post ganglion and norepinephrine from post ganglion to effector organ
Parasympathetic Nervous System (autonomic)
- Pre ganglion (CNS) and post Ganglion (PNS)
- post ganglion lie in or right next to organ it effects
- uses acetalcholine for both pre and post ganglion
The maintenance of the extracellular fluid constituents relatively constant.
Homeostatic Control: local response vs. reflexes
Steady State
the amount of substance is constant within a compartment and does not change with time
- Input = output
- not necessarily an equilibrium state
- requires energy expenditure to maintain
condition in which opposing forces are balanced
- No net transfer of substances or energy
- no barriers to movement of component between compartments
- no energy expenditure to maintain
Feed Forward
Anticipates the changes in regulated variables
Improves the speed of homeostatic responses
reduces amount of deviation from the set point
Adrenal cortex
Part of adrenal gland (sits above kidneys)
Produces steroid hormone cortisol
Tropic Hormone
A hormone that stimulates the secretion of another hormone (some of these are produced by the anterior and posterior pituitary gland- LH, FSH, TSH, GH, Prolactin, ACTH)
ACTH (adrenocorticotripic hormone)
Produced by Anterior Pituitary
CRH --> ACTH --> Cortisol
Acts on Adrenal Cortex to secrete cortisol (cortisol responds to stress, immune system, development)
Hypothalamic Hormones:
DA--> Prolactin
Secreted by fat cells
Stimulates Thyroid to produce T3 and T4 for high metabolic function (to break down fat)
Leptin -> TRH -> TSH -> T3, T4
Can be due to lack of dietary iodine -> this reduces production of T3 and T4
This causes stimulation of TRH and TSH to cause goiter (overgrowth of the thyroid gland), cretinism
Heparin: prevents prothrombin from forming thrombin
Coumadin/Warfarin: prevents production of Vit K, which is essential to create prothrombin. (3 day delay)
In vitro: Agents sequester Ca+ with citrate or oxalate to prevent it's use in coagulation
It's a protease made from Plasminogen
Dissolves clots formed in the body
Thrombocytes (platelets)
Cell fragments from megakaryocytes
Buffers H+ to control pH of ECF
Discoid shaped, no organelle or nucleus
the clotting of intravascular blood. emboli are bits of a thrombus that break off, travel and occlude other blood vessels
Hemostasis requires these molecules:
Calcium and Potassium
Adrenergic synapses
Dopamine, Norepinephrine, Epinephrine
Essential role in consciousness, motivation and BP regulation.
GABA and Glycine
Inhibitory transmitters
Effect gated chloride channels
Effect CNS (GABA- brain, Glycine- Brainstem, Spinal cord)
GHRH, GH, Somatostatin and IGF1 relationship
Somatostatin is released by the Hypothalamus to inhibit GH from being released in the pituitary.
IGF1 increases somatostatin
Exogenously dissolves clots