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185 Cards in this Set
- Front
- Back
What is the advantage of a closed circulatory system over an open one?
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It can move blood more efficiently.
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Which heart chamber supplies oxygenated blood to the heart muscle
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left ventricle
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A three-chambered heart
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) has two atria and one ventricle
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Which heart chamber is the most muscular?
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the left ventricle
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In humans, the tricuspid valve is found
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between the right atrium and the right ventricle
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Why is it important that the atrioventricular (AV) node produce a delay between the contraction of the atria and the contraction of the ventricles?
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It allows the ventricles to fill to capacity
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Ventricles force blood directly into
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arteries.
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The cardiac cycle is
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the alternating relaxation and contraction of heart chambers.
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Which blood constituent makes up more of the volume of blood?
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) plasma
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Erythrocytes are produced in the
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) bone marrow.
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WBC's
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) protect body from microbes.
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Which of the following does NOT play a role in blood clotting?
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albumin
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All hormones are
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delivered to their target tissue by the bloodstream
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) You go to the doctor and are given a shot of hormone as treatment for your condition. The doctor tells you that the shot won't start to work for about 18-24 hours. Based on the amount of time that it takes for the hormone to work, which of the following categories is the hormone most likely to belong to?
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) steroid hormones
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Hormones that react with protein receptors on the surface of the target cell are
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peptide and amino acid
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Proteins which identify a cell as a target cell for a hormone are called
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receptors.
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Water-soluble hormones bind to molecules in the ________ of the target cell
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plasma membrane
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Most of the steroid hormones are synthesized from
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) cholesterol.
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Which of the following is an example of a positive feedback control system?
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During birth, the baby's head presses against the cervix and stretches it; stretch of the cervix stimulates the release of oxytocin; oxytocin causes contractions of muscles in the uterus; this pushes the baby against the cervix harder, increasing the stretch of the cervix.
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The ________ pituitary releases hormones produced from cells in the hypothalamus.
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posterior
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Which of the following secretes releasing and inhibiting hormones?
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hypothalamus
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The cells that control the secretion of all of the hormones produced by the pituitary are in the
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hypothalamus.
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) Which is NOT an effect of thyroxine
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) increasing body temperature
B) stimulating metabolic rate C) stimulating growth of the nervous system D) triggering the metamorphosis of tadpoles |
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Which hormone decreases blood glucose concentrations
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) insulin
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Glucagon increases blood glucose by activating an enzyme which breaks down glycogen which has been stored primarily in the
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) liver.
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Which of the following stimulates the storage of glucose
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) insulin
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Which portion of the neuron typically receives information
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dendrite
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Which portion of the neuron contains receptor proteins
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dendrite
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Which of the following is an important similarity between the endocrine system and the nervous system
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The transmitters from both cause a change in target cells throughout the body.
B) Both involve both electrical and chemical aspects. C) The speed of response is the same. D) Both transmit their compounds into the bloodstream. |
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Which of the following represents the direction a nerve impulse travels within a single neuron?
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dendrite cell body axon synaptic terminal
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An excitatory postsynaptic potential will stimulate
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) the opening of sodium channels.
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The negative resting potential of a neuron is due to
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the action of the sodium-potassium pump.
B) the trapping of large negative organic molecules inside the cell. C) diffusion of potassium ions out of the cell. |
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) Neurons (and most other animal cells) have a negative inside potential because
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) they leak potassium through open channels in the plasma membrane.
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) In neurons, ________ ions are at higher concentration inside the cell and ________ ions are at higher concentration in the extracellular fluid.
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K; Na
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In a nerve cell at its resting potential ________ are closed
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sodium channels
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The resting potential of neurons is between ________ millivolts.
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-40 and -90
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) The sodium-potassium pump pumps
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potassium in and sodium out of the cell
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) Axons
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carry an action potential in the direction of a synapse.
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The intensity of the stimulus is indicated by the ________ of action potentials
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) frequency
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Which of the following most accurately describes why your brain can distinguish lights from sounds.
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Because the brain monitors which action potentials come from the eye and which action potentials come from the ear.
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The kinds of peripheral neurons that are responsible for involuntary responses to extreme danger or stress are the
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) sympathetic.
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Which of the following are found in the human central nervous system?
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) spinal cord
B) forebrain (cerebrum) C) hypothalamus D) all of these |
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In a goldfish, information from the eyes is processed by the
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) midbrain.
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Most brain cells are ________ neurons
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) association
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What type of neuron will activate the biceps muscle in your arm?
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) motor
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The cell bodies of motor neurons are located
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) in the gray matter of the spinal cord.
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) The autonomic nervous system controls
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contraction of involuntary muscles
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If an animal is especially coordinated in its movements, it will probably have a larger than normal
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) cerebellum.
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The part of the brain that controls involuntary actions, such as breathing is the
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hindbrain.
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The structure responsible for transferring short-term memories into long-term memories is the
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) hippocampus.
. |
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Which of the following is a mechanoreceptor
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) hair cell
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) The fovea of the human eye is
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the part of the retina that produces the sharpest image.
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The hormones produced by the pituitary that are primarily responsible for the onset of puberty are
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luteinizing hormone (LH) and follicle stimulating hormone (FSH).
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What is the function of Sertoli Cells?
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regulate sperm production
) nourish the developing sperm |
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What is the function of an acrosome
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) It contains enzymes used to dissolve the protective layers around the egg.
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Which hormone stimulates the production of testosterone
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) luteinizing hormone
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Sperm are stored in the
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epididymis.
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The epididymis connects
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testis and vas deferens.
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In humans, oogenesis is halted in the ________ until pituitary hormones stimulate a continuation of division.
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) first meiotic division
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) The egg that is released from the ovary during ovulation is known as a(n)
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secondary oocyte.
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In humans, fertilization normally occurs in the
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) oviduct.
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Ovulation occurs due to a surge in
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LH concentrations.
. |
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) In which structure would a corpus luteum be located?
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ovary
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Gonadotropin releasing hormone (GnRH)
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stimulates the release of FSH and LH.
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Which of the following reproductive events occurs only in females?
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) Gamete production results in both gamete and polar body formation
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Erection of the penis occurs by
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increased blood flow into it.
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Vasectomy and tubal ligation result in
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an interruption of the path taken by egg or sperm
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) If each of the vas deferens of a male human were cut, his semen would not contain
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sperm.
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A fertilized oyster egg develops into a free-swimming larval stage called a veliger. The veliger later settles and grows a shell. This is an example of
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) indirect development.
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Which of the following statements regarding extraembryonic membranes is TRUE?
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The amnion encloses the embryo in a watery environment
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Which extra-embryonic membrane lies immediately beneath the shell of a reptile embryo?
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chorion
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) Which is the BEST definition of cleavage (as applied to embryos!)?
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) early rapid division of the zygote
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At the blastula stage, the embryo consists of
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a hollow ball of cells.
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If an animal is missing its outer layer of skin upon birth, which of the following might cause it?
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) loss of ectoderm
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The nervous system forms from the
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ectoderm.
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The result of gastrulation is
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) a three-layered embryo.
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Humans are not born with webs between their fingers due to the process of
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) programmed cell death.
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If a cell divides by mitosis so that one cell eventually becomes part of the brain and the other cell becomes part of a salivary gland, the cells have
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differentiated.
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Which of the following is TRUE of stem cells?
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They can become other, specialized kinds of cells.
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) Induction refers to
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) substances from one embryonic cell influencing the development of other cells.
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A human embryo is known as a fetus after
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) 8 weeks.
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) At what stage does a human embryo implant in the uterus?
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) blastocyst
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Which portion of the blastula becomes the embryonic placenta
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chorion
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Which of the following cannot cross the placenta?
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) alcohol
B) cocaine C) AIDS virus D) nicotine E) All of these cross the placenta. |
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Most fetuses can first survive outside the womb after a minimum of
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seven months.
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Deoxygenated
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Vena Cava
R. Atrium R. Ratrioventricular Valve R. Ventrical R. Semiluar Vavle Pulmonary Artery Lung |
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Oxygenated
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Pulmoniary Veins
L Atrium L Ratroventricular Valve L. Ventrical L. Semilunar Valve Aorta Body |
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Homeostasis
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maintaines eternal balances by telling the body what to do. It maintains through the nervous system and the endocrine system.
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Endocrine System
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helps regulate mood, growth and development, tissue function, metabolism, as well as sexual function and reproductive processes.
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Extracellular Fluid (Outside of Cell)
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the volume of body fluid excluding that in cells. ECF includes the fluid in blood vessels (plasma) and fluid between cells (interstitial fluid).
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Interstitial fluid
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Fatty fluid between cells, too much fluid will cause swelling.
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Plasma
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Used to Treat Clotting
Major portion of blood. contains albumin |
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Albumin
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A protein manufactured by the liver
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Mechanisms of Homeostasis
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Sensory receptors
Detect stimulus (ie., nerve ending) Integration Selects response (such as the brain) Effector Carry out response (a muscle or gland) Note: If a neg feedback the system cancels or conteracts the effect. |
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Negative Feedback
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NOte: You have more neg feedback than pos.
Analogy for your body is like a furnance thermostat. (Maintain the body temp) Helps maintain normal body ranges. |
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hypothalamus
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small structure at the base of the brain that regulates many body functions, including appetite and body temperature.
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Positive Feedback
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Intensifies the changes. (i.e, childbirth, sexual intercourse)
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Cells construct tissues and there are only 4 types of tissues
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Epithelia - Membranes that cover the outside of a body and line its cavities (2 types, external is a barrier, no water can get into your body. Internal allows for movement of gases) continual replacement., they form glands (Exocrine glands like sweat glands and Endocrine glands those that produce hormones. Very thin, one cell thick.
Connective - provides strength and connectivity. Loose - holds tissue to make organs., fibrous - tendons, ligaments, specialized, cartlage, bone. Muscle - specialized for contraction., specalized cells are called muscle fibers, 3 types, skeletal, cardiac, smooth. Nervous - cells called neurons, transmits info |
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Tissues make organs (2 tissues that function together)
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skin, heart, kidney
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Organs make organ systems
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2 or more organs that work to perform a common function. (ie., digestive system, stomach, intestines, liver, pancreas)
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Organ system helps us
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respiring (lungs)
circulating blood (heart, arteries) feeding digesting sensory reproducing |
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Epithelial Tissues
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Cuboidal: Cube-shaped with nuclei centrally located
Found in thyroid, pancreas, salivary glands & line kidneys Function: secretion & absorption A. Squamous (simple): (lung) membranes, blood vessels Function: diffusion Squamous (stratified): on the outer surface of skin Function: protection (especially from dessication Columnar: long, column-like cells with nuclei usually located at the base of cells Function: absorption (found in the intestines) |
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Specialized Connective Tissue
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Adipose Tissue: loose, irregular arrangement of fibers. Fat cells, stores energy and cushions delicate organs
Cartilage: extensive, rigid extracellular matrix. Chondrocytes are cartilage producing cells. Function: flexible support structure, shock absorption Bone: intercellular matrix contains numerous fibers & water, and inorganic salts. Function: support structure & protection for vital organs Blood: transport gases, nutrients, waste; Four elements of blood: Erythrocytes Red cells Leukocytes - white cells immune system Platelets: blood clotting, produced in bone morrow Plasma - 90% water. |
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Muscle Tissue
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Fibrous proteins gives the muscle stripes.
Skeletal - voluntary (looks like slits)attached to the bone, closely connected. Indvidual cells are called muscle fibers, very, very thin and long, they contain myofibrils Cardiac - one nucleous per cell, involuntary connected end to end (only in the heart)Sinoatrial Node the pacemaker, give it spontanoeus activity (rate that your heart will beat. not closely attached cells., gaps in between cell for communication. has a nucleious, depends on calcium Smooth muscle - no strips. looks smooth. located in intestines, blood vessels, involuntary. closely attached, slow contractions by Autonomic Nervous Sytem. (bladder is the exception) |
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Nerve
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4 major parts, specalized for reception.
Dendrites - Rec Signal Axon - carries signal to synaptic terminals. cell body - maintains intgrety Synaptic - carries signal to other cells |
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Ectoderm
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The outer most of the three primary germ layers of the embryo, from which the skin, nerve tissue and sensory organs develop.
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Organ systems, Organs,& Tissues make up the Digestive System
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The animal body contains organ systems, each composed of several organs, which are in turn composed of several types of tissue.
Organ systems consist of 2 or more interacting organs. Organ systems: Digestive, urinary, immune, respiratory, circulatory, nervous, muscular, skeletal, endocrine, reproductive |
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External epithelia: your skin is really an organ
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Mammalian skin, a representative organ, in cross section
Dermis permeated by arterioles. Arterioles feed blood pumped from the heart into a dense network of capillaries that nourish both derma & epidermal tissue.. |
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Muscles
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exert a force by coordinated contraction (made up of fibers, different amt of fibers used based on what you are trying to do.
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Skeleton
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provides a support framework (light and rigid)
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Myofibrils
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Contractile cylinders that extend the length of the fiber
Each myofibril is surrounded by a sarcoplasmic reticulum containing lots of Calcium ions (Ca2+) |
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plasma membrane of each muscle fiber
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is periodically indented close to the sarcoplasmic reticulum of the myofibrils and the indentations are called T tubules
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Skeletal Muscle Structure
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A muscle is surrounded by connective tissue and attached to bones by tendons. It contains from a few to thousands of muscle cells called muscle fibers, often packaged into bundles within the muscle. Each fiber is packed with cylindrical subunits called myofibrils, which contain thick and thin filaments of protein.
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Myofibril Structure and function
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The myofibril is organized into a series of subunits called sarcomeres that show precise arrangements of two special protein filaments that interact to cause a contraction.
Thin filaments are made of actin and some accessory proteins Thick filaments made of myosin; lie in between thin filaments Myosin is capable of making temporary connection to actin with structures called cross-bridges This interaction starts the contraction process which shortens the sarcomere |
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Myofibril Structure and function
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The myofibril is organized into a series of subunits called sarcomeres that show precise arrangements of two special protein filaments that interact to cause a contraction.
Thin filaments are made of actin and some accessory proteins Thick filaments made of myosin; lie in between thin filaments Myosin is capable of making temporary connection to actin with structures called cross-bridges This interaction starts the contraction process which shortens the sarcomere |
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Myofibril Structure and function (cont)
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The myofibril is organized into a series of subunits called sarcomeres that show precise arrangements of two special protein filaments that interact to cause a contraction.
Thin filaments are attached to Z lines that separate each sarcomere subunit The regular arrangement of thick and thin filaments and Z lines in each myofibril gives the striped appearance to each muscle fiber |
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Muscle fiber, myofibril, sarcomeres and filaments
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(a) Each muscle fiber is surrounded by plasma membrane that burrows inside, forming T tubules. The sarcoplasmic reticulum surrounds each myofibril within the muscle cell. (b) Each myofibril consists of a series of subunits called sarcomeres, attached end to end by proteins called Z lines.
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myofibril, sarcomeres
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(b) Each myofibril consists of a series of subunits called sarcomeres, attached end to end by proteins called Z lines. (c) Within each sarcomere are alternating thick and thin filaments, which can be connected by cross-bridges (projections of the myosin molecules that make up the thick filaments).
(a) Repeated cycles of cross-bridge attachment, bending, release, and reattachment result in muscle contraction |
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The Neuromuscular Junction
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Motor neurons connect the brain to a muscle or parts of a muscle.
The brain determines the frequency and number of fibers stimulated, this determines the degree of contraction of the muscle. The action potential is the signal from the brain to the muscle (a) Diagram of a neuromuscular junction in cross section. Action potentials in the motor neuron stimulate the muscle fiber membrane, which lies in folds beneath the terminal. |
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The Neuromuscular Junction cont.
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The action potential is transferred into the muscle fiber and passes down the T tubules:
Causes sarcoplasmic reticulum to release Calcium ions (Ca2+) The Ca2+ unlocks the binding sites on actin Myosin cross-bridge initiates contraction using ATP for energy (a) Diagram of a neuromuscular junction in cross section. Action potentials in the motor neuron stimulate the muscle fiber membrane, which lies in folds beneath the terminal. |
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The Human Skeleton
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Vertebrate skeleton functions
Supports the body and protects internal organs (rib cage) Attachment site for muscles Produces blood cells Storage site for calcium and phosphorus Assists sensory transduction—middle ear bones, jaw bone The human skeleton, showing the axial skeleton (tinged in blue-gray) and the appendicular skeleton (bone color). |
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The Human Skeleton cont
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Vertebrate skeleton functions
Skeleton made up of two components A. Cartilage B. Bone Both types are living cells embedded in a matrix of collagen The human skeleton, showing the axial skeleton (tinged in blue-gray) and the appendicular skeleton (bone color). |
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Cartilage Structure and Function
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Cells are called chondrocytes and secrete a flexible elastic matrix of extra-cellular collagen that binds the cells together.
Provides flexible support—ears, nose, trachea, larynx, bronchi Connects bones but provides flexibility — ribs joined to sternum Provides shock absorbency Covers the ends of bones at joints Pads in the knees, inter-vertebral discs |
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Bone Structure and function
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Bones are organized into two parts:
Outer shell of compact bone that is hard, strong and dense, attaches to muscle tendons Inner spongy bone that is porous, light and filled with blood vessels and bone marrow There are three bone cell types: Osteoblasts – new bone cells, by secreting calcium phosphate into collagen Osteocytes – old bone cells trapped with hardened bone but alive and interconnected Osteoclasts – bone dissolving cells, work to re-model bones in response to demands. 5-10% of bone mass re-modeled per year . Work with osteoblasts to form osteons, a basic unit structure of compact bones, and to repair fractures |
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Bone Structure and function cont.
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2. Bone marrow
makes red & white blood cells, platelets Storage and regulation of calcium and phosphorus levels via blood stream Some fat storage |
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The Structure of Bone
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Osteoblasts and osteoclasts routinely build osteons
They also repair bone fractures (a) A typical bone, such as those in the arms and legs, is made of an outer layer of compact bone and spongy bone inside. For simplicity, blood vessels are not shown. (b) Osteons are clearly visible in this micrograph. Each includes a central canal containing a capillary. The capillary nourishes the osteocytes, embedded in the concentric rings of bone material. |
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Hinge Joint
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Ligaments and cartilage provide stability for the joint so the muscles can work smoothly
Muscles and tendons move the bones. Tendons are elastic and store energy to balance muscle effort Muscles work in opposition at joints for balance and control The human knee—a hinge joint—showing antagonistic muscles (here, the biceps femoris and the quadriceps of the thigh), tendons, and ligaments. (The tendon of the biceps femoris has been cut for viewing purposes.) The complexity of this joint, coupled with the extreme stresses placed on it during activities such as jumping, running, or skiing, make it very susceptible to injury. |
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The Steps in Bone Repair
|
Temporary callus forms at fracture
Osteoclasts and osteoblasts form new bone Osteoclasts dissolved fragments and broken areas Osteoblasts and osteoclasts reconstruct new osteons Osteoclasts then sculpt new bone into original shape |
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A sarcomere is made up of
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Thick and thin filaments
|
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A muscle fiber contracts because
|
a receptor potential causes release of Ca++
B. interaction of thick and thin filaments C. ATP energy is released |
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The degree of a muscle’s contraction is dependent on
|
The number of muscle fibers stimulated
|
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Which body structure is responsible for regulating calcium and phosphorus levels in the blood?
|
bone marrow
|
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Osteoclasts are responsible for:
|
bone dissolution
|
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Muscles cause appendages to move because the muscles are
|
in opposition.
|
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Gas Exchange
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Gases move in and out by bulk flow.
co2 and 02 exchange in lungs by diffusion gases dissovled in blood are transported by bulk flow. 02 & co2 exchange in tussues by diffusion. |
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Features Facilitating Diffusion
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Gas exchange depends on diffusion
Exchange surface must be moist, as gases have to be dissolved in water in order to diffuse Very thin cells line respiratory surfaces Large surface area in contact with the environment Relatively easy for aquatic organisms; big challenge for terrestrial animals. |
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Evolution of Respiratory System
|
Evolutionary changes in respiratory system
Smaller organisms rely on diffusion through epidermis (flatworms) Circulatory systems move gases around (annelids, molluscs) Large animals evolved respiratory systems with very large surface areas for diffusion Internalizing the respiratory systems kept the surfaces moist Respiratory epithelia surface cells are very thin to facilitate diffusion |
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Gas Exchange cont
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Aquatic environments
gills – increased surface area Terrestrial environments Integumentary exchange – Diffusion across body surface (worms) Book lungs – Air enters air pockets that extend into blood filled chambers (spiders) Tracheae/Spiracles – internal tubes (insects) Lungs – chambers (vertebrates) The gill reaches its greatest complexity in the fish, where it is made of thin folds of tissue called filaments and is protected under the operculum, a bony flap. A one-way flow of water is maintained over the gill by the pumping of water through the mouth and out the opercular opening. |
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Exchanging Gases
|
Gills elaborately branched or folded
Lungs – chambers containing moist surfaces The gill reaches its greatest complexity in the fish, where it is made of thin folds of tissue called filaments and is protected under the operculum, a bony flap. A one-way flow of water is maintained over the gill by the pumping of water through the mouth and out the opercular opening. |
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Mechanics of Breathing
|
Mechanics of breathing: bulk flow of gases into animal
Inspiration — active inhalation of air Frogs gulp; reptiles move guts Mammals breathe with chest muscles that create negative pressure Diaphragm and rib muscles contract, making the chest cavity larger Chest expansion causes the lungs to expand; vacuum draws in air Expiration — occurs when muscles relax Flexible cartilage that connects the ribs to the sternum returns to normal position and this compresses lungs to help expel air (a) During inhalation, rhythmic nerve impulses from the brain stimulate the diaphragm to contract (pulling it downward) and the muscles surrounding the ribs to contract (moving them up and outward). The result is an increase in the size of the chest cavity, causing air to rush in. (b) Relaxation of these muscles (exhalation) allows the diaphragm to dome upward and the rib cage to collapse, forcing air out of the lungs. |
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Control of respiration
|
Regulation of breathing by carbon dioxide CO2 levels in the blood.
Respiration center in brain: medulla generates nerve impulses that stimulates contraction of diaphragm and chest muscles Respiration center tries to maintain a constant level of CO2 in the blood |
|
Control of respiration cont.
|
CO2 level in the blood monitored by CO2 receptors in medulla
Elevated CO2 levels in blood signals need for more O2, causing receptors in increase breathing rate. Increase in activity levels initiates higher breathing before CO2 rise occurs in blood; anticipates demand |
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The Human Respiratory System
|
The conducting portion
Carries air to the lungs Warms and moistens air moving through it Structural parts: nose and mouth, pharynx Larynx and epiglottis (flap that closes when swallowing); vocal cords Trachea; bronchi lead to lungs In lungs, smaller bronchioles lead to alveoli where diffusion occurs Ciliated epithelia (surface cells): Lines the trachea, bronchi, and bronchioles Filter dust particles & bacteria, passed up through trachea and expelled as mucus (phlegm) or swallowed Smoke paralyzes cilia and so they cannot remove smoke residue |
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The Human Respiratory System cont.
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(a) Air enters mainly through the nasal cavity and mouth and passes through the pharynx and the larynx into the trachea. The epiglottis prevents food from going down the trachea. The trachea splits into two large branches, the bronchi, which lead into the two lungs. The smaller branches of the bronchi, the bronchioles, lead to the microscopic alveoli, which are enmeshed in capillaries, where gas exchange occurs. The pulmonary artery carries deoxygenated blood (in blue) to the lungs; the pulmonary vein carries oxygenated blood (in red) back to the heart. (b) Close-up of alveoli (their interiors are shown in this cut-away section) and their surrounding capillaries.
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The Human Respiratory System cont.
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Gas exchange portion
Alveoli - site of gas exchange in the lungs Alveoli have an enormous surface area (75 sq. m. or 800 sq. ft) Small grape-like structures on the end of each bronchiole Thin layer of moisture on the inside surface of each alveolus Capillaries surround the alveoli, each are only one cell thick Gas exchange occurs in alveoli, because gases dissolve in a thin layer of moisture on the lung side of the alveoli Dissolved gases diffuse across alveoli membrane into adjacent capillary membrane Pulmonary arteries deliver deoxygenated blood from heart Pulmonary veins return oxygenated blood to heart |
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Mechanisms of gas exchange and transport
|
The simple story of gas exchange in alveoli:
CO2 diffuses out of blood where [CO2] is high, into the air in alveoli, where [CO2] is low. O2 diffuses from air where [O2] is high into the blood, where [O2] is low. The real story: Absorption of oxygen from plasma by hemoglobin in the RBC maintains a low concentration of oxygen dissolved in blood plasma, forcing diffusion of oxygen into blood plasma. Carbon dioxide is actually transported in blood to lungs in three forms: attached to hemoglobin (20%) dissolved in blood plasma as a gas (10%) dissolved as bicarbonate ions (70%) The diffusion of carbon dioxide out of the blood plasma and RBC into alveoli changes the shape of hemoglobin molecules allowing it to absorb the maximum amount of oxygen |
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Gas Exchange betweenAlveoli and Capillaries
|
The alveoli and capillary walls are only one cell thick, very close to one another, and the cells are coated in a thin layer of fluid. This allows gases to dissolve and diffuse easily between the lungs and circulatory system.
|
|
Gas Exchange: Transportof Oxygen from lungs
|
O2 diffusesthrough lungcapillary wall
O2 carried totissues boundto hemoglobin O2 diffusesthrough tissuecapillary wall |
|
Gas exchange in the body tissue capillaries
|
What happens at the body tissue capillaries to force oxygen into tissues and carbon dioxide out?
The simple story: High concentration of CO2 in tissues is forced into blood by diffusion High concentration of O2 in blood forces it into tissues by diffusion The real story: Enzymes in red blood cells convert dissolved carbon dioxide in plasma to bicarbonate, lowers dissolved plasma CO2 levels creating a concentration gradient, enhances diffusion of CO2 into blood The rising CO2 level in blood force it to bind with hemoglobin, changing the molecules shape and forcing it to dump O2 which raises dissolved levels, enhancing diffusion out of blood to tissues |
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Gas Exchange: Transportof Carbon Dioxide
|
1a Dissolves in plasma,
due to low concentration 1b Converted tobicarbonate in RBC 1c Bound tohemoglobin. CO2 diffusesthrough tissuecapillary wall CO2 is carriedto the lungs 3.CO2 diffuses through lung capillary wall, bicarbonate is converted back to CO2 |
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Respiration problems
|
Smoking: results in lung cancer and emphysema
Asbestos: causes lung cancer Carbon Monoxide: colorless and odorless gas that binds to hemoglobin and prevents oxygen absorption at very low concentrations. A silent killer…. Allergens and asthma: many triggers in the environment |
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Respiration Diseases
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Bronchitis
Pneumonia Emphysema Alveoli breakdown Cigarettes, marijuana Second-hand smoke Lung cancer Cystic fibrosis |
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Vertebrate CirculatorySystem: Functions
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Transport O2 and CO2 - gases from the respiratory system
Distributes nutrients - from digestive system to body Transports waste - cells to excretory system (kidney and liver) Distributes hormones - from endocrine glands & other organs Regulates body temperature – adjust blood flow Protection against disease and blood loss - delivery of white blood cells to fight infections; clotting agents to wounds |
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Circulatory System Basics
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Circulatory systems have three majors parts:
1. Fluid — blood oxygen, wastes and other components 2. System of channels — blood vessels arteries, veins, capillaries Conduct blood throughout the body 3. A pump — the heart Circulates blood through the vessels and throughout the body |
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Types of Circulatory Systems
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Open systems
Open space within the body cavity—hemocoel Arthropods (insects, spiders, and crustaceans) Most mollusks (snails and clams) Heart & vessels Closed Systems Confined blood in continuous vascular network Pumping heart & vessels Some invertebrates (earthworm, cephalopod molluscs) All vertebrates In hemocoel, tissues & organs directly bathed in blood. Open: heart valves shut, forces blood into hemocoel, relaxes and blood drawn back into vessels/heart Closed: more rapid flow more efficient transport of wastes & nutrients and higher blood pressure than in open CS |
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Vertebrate Circulatory System
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The Heart
Muscular organ capable of strong contractions to force blood to flow Works continuously About 2 billion beats in an animals life time Heart pumping sustains blood pressure throughout animal body |
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Vertebrate Circulatory System cont.
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Heart Structure
Atria –collect blood from venous system sends blood to ventricles Ventricles- send blood to lungs and body Greater complexity in heart structure among vertebrates due to challenges of life on land (larger heavier bodies) |
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Evolution of heart structures
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Fish circulatory system
Heart (atrium & ventricle) Low level of oxygen delivery Amphibian and reptile circulatory system Start of double circulation system that increased pressure to body capillaries Two atria, one ventricle Inefficient mixing of venous and arterial blood, reduced oxygen levels sent to body Reptiles have partial septum dividing ventricle Mammal and Bird circulatory system (+ crocodiles) Complete separation of arterial and venous blood (double circulation) Separate loop from heart to body capillaries allows for higher pressure keeps oxygen levels at the maximum 2 atria, 2 ventricles |
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The Evolution of theVertebrate Heart
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(a) The earliest vertebrate heart is represented by the two-chambered heart of fishes. (b) Amphibians and most reptiles have a heart with two atria, from which blood empties into a single ventricle. Many reptiles have a partial wall down the middle of the ventricle. (c) The hearts of birds and mammals are actually two separate pumps that prevent mixing of oxygenated and deoxygenated blood. Note that in this and in subsequent illustrations, oxygenated blood is depicted as bright red, while deoxygenated blood is colored blue.
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Human Heart
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The heart is drawn as if it were in a body facing you, so that right and left appear reversed. Note the thickened walls of the left ventricle, which must pump blood much farther through the body than does the right ventricle, which propels blood to the lungs. One-way valves, called semilunar valves, are located between the aorta and the left ventricle, and between the pulmonary artery and the right ventricle. Atrioventricular valves separate the atria and ventricles.
Deoxy Vena Cava R. Atrium R. Ratrioventricular Valve R. Ventrical R. Smiluar Valve Pulmonary Artery Lung Oxy Pulmonary Veins L. Atrium L. Ratrooventricular Valve L Ventrical L Semiluar Valve Aorta Body |
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The heart and its functions
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The heart beats about 100, 000 times a day.
The cardiac cycle Both atria contract at the same time A fraction of a second later the ventricles contract at the same time Then the atria and ventricles relax and cycle starts again One-way valves make sure blood goes the right direction Measuring blood pressure Systole — period of ventricle contraction Diastole — relaxation of all the chambers |
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The Cardiac Cycle
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Systole: Ventricles contract
Diastole: Heart relaxes; atria fill passively |
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Measuring Blood Pressure
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Cuff inflated until no pulse audible
Pressure released until pulse is first heard Cuff pressure is just lower than left ventricle Systolic Continue deflating cuff till pulse inaudible Cuff pressure less than lowest arterial pressure Diastolic Report pressures as: Systolic : Diastolic, 140:80 Blood pressure is measured with an inflatable blood pressure cuff and a stethoscope. The cuff is inflated until its pressure closes off the arm’s main artery, blood ceases to flow, and no pulse can be detected below the cuff. Then the pressure is gradually reduced. When the pulse is first audible in the artery, the pressure pulses created by the contracting left ventricle are just overcoming the pressure in the cuff and blood is flowing. This is the upper reading: the systolic pressure. Cuff pressure is then further reduced until no pulse is audible, indicating that blood is flowing continuously through the artery and that the pressure between ventricular contractions is just overcoming the cuff pressure. This is the lower reading: the diastolic pressure. The numbers are in millimeters of mercury, a standard measure of pressure also used in barometers. |
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Coordination of heart muscle cells
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Heart composed of cardiac muscle tissue cells
Smooth coordinated contraction of heart muscle cells controlled by electrical signals (impulses) between muscle cells Impulses cross between cells through gap junctions Cardiac muscle cells are branched. Adjacent plasma membranes meet in folded areas that are densely packed with gap junctions (pores), which connect the interiors of adjacent cells. This arrangement allows direct transmission of electrical signals between the cells, coordinating their contractions. |
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Coordination of Heart Activity
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Atrioventricular and semilunar valves
Sinoatrial node (SA node): pacemaker Atrioventricular node (AV node) Influences on heart rate Parasympathetic nervous system - decreases heart rate Sympathetic nervous system - increases heart rate Hormones |
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Coordination of Heart activity cont.
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Sinoatrial node (SA node or pacemaker)
Sends electrical impulse that starts contraction of left and right atria Impulse travels to atrioventricular node (AV node) Signal from SA to AV is delayed by about 1/10 th of a sec. Enough time for blood to leave atria and fill ventricles Impulse continues along excitable fibers (i.e., bundle of His to Purkinje fibers) to ventricles, which contract together Influences on heart rate –SA beat is about 100 per minute Parasympathetic nervous system - decreases resting heart rate (70) Sympathetic nervous system - increases heart rate during exercise (120). Caused by hormones - epinephrine or adrenalin |
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The Heart’s Pacemakerand Its Connections
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The sinoatrial (SA) node, a spontaneously active mass of modified muscle fibers in the right atrium, serves as the heart’s pacemaker. The signal to contract spreads from the SA node through the muscle fibers of both atria, finally exciting the atrioventricular (AV) node in the lower right atrium. The AV node then transmits the signal to contract through bundles of excitable fibers that stimulate the ventricular muscle.
One impulse from the SA node starts the cycle AV Node triggers the fibers to contract the ventricles Heart attacks disrupt the cycle and fibrillation occurs Defibrillators reset pacemaker |
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Composition of Blood
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Plasma—55% to 60% of blood volume
90% water, yellowish Three important proteins Albumins maintain osmotic pressure in arteries, veins Globulins transport nutrients, help immune system Fibrinogen helps form blood clots Hormones Nutrients Gases Ions Waste |
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Blood Cells
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Blood cells
Make up about 40-45% of blood volume, three types of cells: Red blood cells (RBCs) — erythrocytes, 99% of the total cellular component in the blood Carry O2 bound to hemoglobin molecules in cell Each hemoglobin can carry 4 oxygen molecules, greatly enhancing capacity of blood Hemoglobin binds O2 in lung capillaries [O2] high CO2 Hemoglobin releases O2 in tissues [O2] low |
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Hemoglobin
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A molecule of hemoglobin is composed of four polypeptide chains (two pairs of similar chains), each surrounding a heme group. The heme group contains an iron atom and is the site of oxygen binding. When saturated, each hemoglobin molecule can carry four oxygen molecules (eight oxygen atoms).
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Blood cells cont
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Red blood cells are made in bone marrow
Mammalian RBC’s lose their nuclei and live only about 120 days Dead cells are recycled in the liver and spleen, especially to retrieve the iron Body has a negative feedback system to ensure that enough red blood cells are present The system initiates RBC production in the bone marrow and then shuts it off Started when not enough oxygen is present (blood loss, high altitude) Kidney produces a hormone called erythropoietin Hormone production is stopped when adequate oxygen is available |
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RBC Regulation byNegative Feedback
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Red blood cell regulation by negative feedback (change initiates series of events that counteract changes and restores original state)
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The other blood cells
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White blood cells—leukocytes (WBCs) and lymphocytes
Made in bone marrow Five white blood cell types - attack bacteria and viruses as part of the immune system WBC can operate outside of capillaries to attack bacteria and viruses Act like amoeba and engulf foreign particles, then die & turn to pus. Lymphocytes make antibodies for immune system Platelets Cellular fragments from megakaryocyte Produces n bone marrow Function in blood clotting Live only 10-12 days |
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Blood clotting mechanism
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Platelets respond to irregularities in blood vessel walls, such as a tear or cut etc.
Platelets adhere to tear and starts a sequence of events An enzyme , thrombin, converts the dissolved protein fibrinogen in blood plasma to stringy insoluble fibrin The mesh of fibrin traps RBCS and more platelets Platelets contract pulling web of cells and fibrin tighter and starts pulling injured tissues together so that they can heal. Fibrin mesh and RBCs form the hard scab on top of wound |
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Blood Clotting cont
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(a) Injured tissue and adhering platelets cause a complex series of biochemical reactions among blood proteins. These reactions produce thrombin, which catalyzes the conversion of fibrinogen to insoluble fibrin strands.
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Blood Clotting (b)
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(b) Threadlike fibrin proteins produce a tangled sticky mass that traps red blood cells and eventually forms a clot.
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Blood Vessels
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Arteries and arterioles
Thick walled, elastic to withstand high pressure Carry blood away from the heart Capillaries Tiniest vessels; thin, single-cell wall for easy diffusion Exchange of materials between blood & body cells Venules and veins Thin-walled vessels surrounded smooth muscle Low resistance to blood flow Return blood to the heart Blood flow regulated by muscular walls of arterioles Influenced by: Autonomic nerves: usually in response to heat, cold, exercise Hormones Other chemicals released from nearby tissues |
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Distribution of Blood Flow
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Regulated by muscular walls of arterioles
Aterioles determine blood pressure Influenced by: Autonomic nerves Hormones Other chemicals released from nearby tissues |
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The Human Circulatory System
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Most veins (right) carry deoxygenated blood to the heart, and most arteries (left) conduct oxygenated blood away from the heart. The pulmonary veins (carrying oxygenated blood) and arteries (carrying deoxygenated blood) are exceptions. All organs receive blood from arteries, send it back via veins, and are nourished by capillaries (only lung capillaries are illustrated and these are greatly enlarged, since capillaries are microscopic).
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Muscles and connective tissues allow for regulation of blood pressure and flow
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Pre-capillary
sphincters control blood flow into capillaries Arteries and arterioles are more muscular than are veins and venules. Capillaries have walls only one cell thick. Oxygenated blood moves from arteries to arterioles to capillaries. Capillaries empty deoxygenated blood into venules, which empty into veins. The movement of blood from arterioles into capillaries is regulated by muscular rings called precapillary sphincters. |
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Distribution of Blood Flow
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Capillaries:
Tiniest vessels; thin, single-cell wall for easy diffusion Blood flow very slow to help diffusion RBC’s pass through capillary in single file. Three forces at work to move gases and nutrients in and out of capillary via interstitial fluid and then to body cells Concentration gradient: gas exchange with oxygen and carbon dioxide switching places by diffusion from high to low. Same for nutrients High hydrostatic pressure on arterial side forces out plasma fluid containing small ions, nutrients. Leaves behind large proteins, blood cells; lowers osmotic pressure Osmosis brings waste products & water in on venous side |
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Exchanges in capillary
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High hydrostatic pressure on arterial side forces out plasma fluid containing small ions, nutrients
Concentration gradients: High O2 and nutrients in blood Low O2 and nutrients in blood High CO2 and wastes in tissues |
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Lymphatic System
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(a) Lymph vessels, lymph nodes, and two auxiliary lymph organs, the thymus and spleen. Lymph is returned to the circulatory system by way of the thoracic duct, which empties into the vena cava, a large vein. (b) A cross section of a lymph node. The node is filled with channels lined with white blood cells (lymphocytes) that attack foreign matter in the lymph.
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LymphCapillary Structure
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Lymph capillaries end blindly in the body tissues, where pressure from the accumulation of interstitial fluid forces the fluid into the lymph capillaries.
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PlaquesClog Arteries
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Diagrammatic cross section of an artery with a plaque. If the fibrous cap ruptures, a clot will form that can completely obstruct the artery, or the clot can break loose and clog a narrower artery “downstream.”
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