Exam 3 Study Guide
It is important for the cells of an animal’s body to communicate to ensure proper functioning of the whole organism.
Methods of communication:
Direct- Ex. Ions flowing between cardiac muscle cells
Synaptic- Ex. Acetylcholine, dopamine
Paracrine- Ex. Prostaglandin, histamine
Endocrine- Ex. Insulin, estrogen, growth hormone
Be sure to study Table 38-1.
In direct communication- gap junctions link the cytoplasm of adjacent cells, allowing ions and electrical signals to flow between them. This type of communication is very fast but requires the cells to be intimate contact with one another.
- In the other types of communication the “sending” cells release chemical messengers. Receptors- specialized proteins located either on the surface of or inside the receiving cells. Target cells- cells with receptors that bind a messenger molecule and respond to it
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Synaptic communication- electrical signals within individual nerve cells may travel to nearby cells, throughout the brain, or to muscles in the farthest reaches of the body of the body in a fraction of a second
Hormone - chemical messenger that is secreted by the interstitial fluid or bloodstream to target cells.
Paracrine communication- cells release local hormones that diffuse through the interstitial fluid and affect nearby cells.
Endocrine communication- cells, usually in discrete glands, release endocrine hormones that travel in the bloodstream throughout the body.
Prostaglandis- modified fatty acids secreted by cells throughout the body - Endocrine communication begins with the secretion of hormones by endocrine glands.
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Negative feedback- a response to a change that tends to counteract a change and restore the system to its original condition.
Positive feedback- the response to a change enhances the change
Mammalian endocrine system- consists of the endocrine glands and the hormones they produce.
- Hypothalamus-pituitary complex. The hypothalamus is a part of the brain that contains clusters of specialized nerve cells called neurosecretory cells. The Pituitary gland is a pea-sized gland connected to the hypothalamus. Consists of the anterior pituitary and posterior pituitary. If you want to learn more check out What is the objective of merchandising and manufacturing companies?
- Thyroid gland- lies at the front of the neck and produces two hormones: thyroxine and calcitonin.
- Pancreas- produces bicarbonate and several enzymes that are released into the small intestine, promoting the digestion of food.
- Sex organs- produce both gametes and sex hormones.
- Adrenal glands- secrete hormones that regulate metabolism and responses to stress. Consists of the adrenal cortex and the adrenal medulla.
Study figure 38.4, 38.2, and 38.5.
Follicle- stimulating hormone (FSH) and luteinizing hormone (LH) stimulate the production of sperm and testosterone in the testes of males and the production of eggs, estrogen, and progesterone in the ovaries of females.
Thyroid- stimulating hormone (TSH)- stimulates the thyroid gland to release its hormones.
Adrenocorticotropic hormone (ACTH)- causes the release of the hormone cortisol from the adrenal cortex.
Prolactin (PRL)- stimulates the development of milk-producing mammary glands in the breasts during pregnancy We also discuss several other topics like How did andy warhol influence the american pop art?
Growth hormone (GH)- acts on nearly all the body”s cells by increasing protein synthesis, promoting the use of fats for energy, and regulating carbohydrate metabolism.
The hypothalamic regulatory hormones are called releasing hormones or inhibiting hormones, depending on whether they stimulate or inhibit the release of a particular pituitary hormone. Don't forget about the age old question of What are the two components of autonomic nervous system?
Study figure 38.6.
Antidiuretic hormone (ADH)- helps prevent dehydration by causing the kidneys to absorb water and return it to the bloodstream.
Study figure 38.8, 38.9. Know statistics about diabetes.
Atrial natriuretic peptide (ANP)- inhibits the release of ADH and aldosterone and increases the excretion of sodium.
Nervous system has two principle cell types :
- Neurons- receive, process, and transmit information, and control body movements - Glia- assist neuronal function by providing nutrients, regulating the composition of the interstitial fluid that bathes the neurons, protecting against infection, helping to repair damage, fine-tuning communication among neurons, and speeding up the movement of electrical signals within neurons.
Neurons four major structures:
- Dendrites- branched tendrils protruding from the cell body that perform the “receive information” function.
- A cell body- processes signals from the dendrites.
- An axon- extends outward from the cell body and conducts action potentials from the cell body to synaptic terminals at the axon’s end.
- Synaptic terminals - a swelling at the end of an axon of the “sending” neuron. Study figure 39-1, table 39-1, figure 39-2, figure 39-3, figure 39-4. If you want to learn more check out What is required for idea to be facilitated?
Resting potential- an inactive neuron maintains a constant electrical voltage difference, or potential, across its plasma membrane.
Sensory neurons- respond to stimuli from inside or outside the body.
Interneurons- receive signals from the sensory neurons, hormones, and neurons that store memories.
Motor neurons- receive instructions from sensory neurons or interneurons and activate muscles/glands.
Effectors- perform the response directed by the nervous system
Study Figure 39-5 and figure 39-7.
Central nervous system (CNS) - consists of the brain and spinal cord
Peripheral nervous system (PNS)- consists of neurons and axons that lie outside the CNS
Somatic nervous system- motor neurons form synapses with skeletal muscles and control voluntary movement.
Autonomic nervous system- neurons innervate the heart, smooth muscles in the respiratory tract and blood vessels, and many glands, and produce mostly involuntary actions. - Consists of two divisions that innervate the same organs, but with opposing actions: -Sympathetic Division
- Parasympathetic division
Study figure 39-8.
Blood-brain barrier- a capillary system that is far less permeable than capillaries in the rest of the body and selectively transports needed materials into the brain while keeping many dangerous substances out.
All vertebrate brains consist of three major parts:
- Hindbrain- consists of the medulla, pons, and cerebellum
- Midbrain- contains clusters of neurons that contribute to movement, arousal, and emotion.
- Forebrain- includes the thalamus, hypothalamus, and cerebrum
Study figure 39-12, 39-12a, 39-13.
Limbic system- a diverse group of forebrain structures located in a ring between the thalamus and cerebral cortex
Study figure 39-14, 39-15.
Learning has two phases: short- term memory and long-term memory. Chapter 40:
Sensory perception begins with a receptor: a molecule, cell, or multicellular structure that produces a response when it is acted on by a stimulus.
Sensory receptor- a specialized cell that produces an electrical signal in response to specific stimuli.
Study table and figure 40-1, 40-2
Sense organ- a structure that includes both the sensory receptors and accessory structures that play essential roles in detecting specific stimuli.
Receptor potential- when a sensory receptor is stimulated, it produces an electrical signal Thermoreceptors- respond to heat or cold
- Generally, both heat and cold receptors fire action potentials spontaneously at usual skin temperatures of about 77–91ºF
- Cold receptors fire more rapidly at temperatures below 77ºF, whereas warm receptors fire more rapidly at temperatures above 91ºF
- Thermoreceptors in the brain detect core body temperature and activate homeostatic responses to maintain appropriate body temperature
Mechanoreceptors- respond to physical deformation such as stretching, dimpling, or bending of various body parts
Types of mechanoreceptors:
–Receptors in the skin that respond to touch, vibration, or pressure
–Stretch receptors in many internal organs, including the intestines, stomach, urinary bladder, and muscles
–Receptors in the inner ear that respond to sound, gravity, or movement Study figure 40-3.
Mammalian ear performs several different functions:
- Perceives sounds
- Determines direction of gravity
- Detects the orientation and movement of the head
Outer ear- consists of the pina and the auditory canal
Pinna- a flap of skin-covered cartilage attached to the surface of the head: it collects sound waves
Auditory canal- conducts the sound waves from the pinna to the middle ear
Middle ear- consists of the tympanic membrane (or ear drum); three tiny bones called the hammer (malleus), anvil (incus), and stirrup (stapes); and the auditory tube (Eustachian tube)
Study figure 40-4a and 40-4b.
- Small bones transmit vibrations to the inner ear.
- The hollow bones of the inner ear form a spiral-shaped tube called the cochlea. Study figure 40-4cd.
In all animals, vision begins with cells called Photoreceptors.
- These cells contain photopigments, receptor molecules that change shape when they absorb light.
Sclera- a tough connective tissue layer visible as the white of the eye and continuous with the transparent cornea at the front
- Light enters the eye through the cornea.
Aqueous humor- chamber filled with a watery fluid.
Pupil- a circular opening in the center of the colored iris.
Lens- a structure composed of transparent proteins and shaped like a flattened sphere. Vitreous humor- a clear jelly-like substance that helps maintain the shape of the eyeball. Study figure 40-7, 40-8a, 40-8bc.
Nearsighted- light from distant objects will focus in front of the retina, so you will not see them clearly
Farsighted- eyeballs that are too short or corneas that are too flat and focus light behind the retina.
About 7% of men have difficulty distinguishing red from green because they possess a defective gene on the X chromosome that codes for the red and green photopigments.
Chemoreceptors- respond to chemicals in the internal or external environments.
Terrestrial vertebrates have two separate senses that respond to chemicals from outside the body
- Olfaction- the sense of smell
- Gustation- the sense of taste
Study figure 40-11, 40-12
Human tongue bears about 5,000 taste buds.
Five known tastes:
- Umami ( japanese word loosely translated as “delicious”)
Pain is a subjective feeling arising in the brain produced by the stimulation of pain receptors (also called nociceptors).