EXAM #3 Flashcards
Includes all the endocrine glands and
tissues that produce hormones
Endocrine system
Secrete cell product into interstitial fluids around cell or into stream
Endocrine glands
_ are NOT part of the endocrine system
Exocrine glands
secrete cell product onto body surface (internal or external)
- sweat glands
- saliva glands
- digestive tract glands
Exocrine glands
what does the Endocrine system do?
Controls slow, long duration responses
Endocrine system: what does it do?
Regulates _ and _ in body fluids (CA2+)
- fluid balance
- ion concentration
Endocrine system: what does it do?
Regulates absorption of _
nutrients (digestive-insulin)
Endocrine system: what does it do?
Regulates metabolism and _
growth (GH) (Thyroid)
Endocrine system: what does it do?
Regulates sexual characteristics and _
reproduction
Endocrine system: what does it do?
Regulates body’s response to _
stress
- Regulates fluid balance and ion concentration in body fluids
- Regulates absorption of nutrients
- Regulates metabolism and growth
- Regulates sexual characteristics and reproduction
- Regulates body’s response to stress
What the Endocrine system does
Intercellular communication by chemical
messages in 4 ways
- Direct through gap junctions
- Neurotransmitters
- Paracrine factors (local hormones)
- Hormones
Intercellular communication by chemical
messages:
- Released by presynaptic nerve cell
- Produce effects in adjacent postsynaptic cell
- Neurotransmitters
Intercellular communication by chemical
messages:
- Released by most cells into interstitial fluids
- Produce effects in neighboring cells within one tissue
- Paracrine factors (local hormones)
Intercellular communication by chemical
messages:
- Released by endocrine cells into interstitial fluids, diffuse into capillaries
- Produce effects in target cells elsewhere in body
Hormones
Intercellular communication:
Mechanism = _
Transmission = through gap junctions
Chemical mediators = ions, small solutes, lipid-soluble materials
Distribution of effects = Usually limited to adjacent cells of the same type that are interconnected by connexons
Direct communication
Intercellular communication:
Mechanism = Direct communication
Transmission = _
Chemical mediators = ions, small solutes, lipid-soluble materials
Distribution of effects = Usually limited to adjacent cells of the same type that are interconnected by connexons
through gap junctions
Intercellular communication:
Mechanism = Direct communication
Transmission = through gap junctions
Chemical mediators = _
Distribution of effects = Usually limited to adjacent cells of the same type that are interconnected by connexons
ions, small solutes, lipid-soluble materials
Intercellular communication:
Mechanism = Direct communication
Transmission = through gap junctions
Chemical mediators = ions, small solutes, lipid-soluble materials
Distribution of effects = _
Usually limited to adjacent cells of the same type that are interconnected by connexons
Intercellular communication:
Mechanism = _
Transmission = through extracellular fluid
Chemical mediators = Paracrine factors (i.e. histamine)
Distribution of effects = Primarily limited to local area, where concentrations are relatively high. Target cells must have appropriate receptors.
Paracrine communication
Intercellular communication:
Mechanism = Paracrine communication
Transmission = _
Chemical mediators = Paracrine factors (i.e. histamine)
Distribution of effects = Primarily limited to local area, where concentrations are relatively high. Target cells must have appropriate receptors.
through extracellular fluid
Intercellular communication:
Mechanism = Paracrine communication
Transmission = through extracellular fluid
Chemical mediators = _
Distribution of effects = Primarily limited to local area, where concentrations are relatively high. Target cells must have appropriate receptors.
Paracrine factors (i.e. histamine)
Intercellular communication:
Mechanism = Paracrine communication
Transmission = through extracellular fluid
Chemical mediators = Paracrine factors (i.e. histamine)
Distribution of effects = _
Primarily limited to local area, where concentrations are relatively high. Target cells must have appropriate receptors.
Intercellular communication:
Mechanism = _
Transmission = through the circulatory system
Chemical mediators = Hormones
Distribution of effects = Target cells are primarily in other tissues and organs and must have appropriate receptors
Endocrine communication
Intercellular communication:
Mechanism = Endocrine communication
Transmission = _
Chemical mediators = Hormones
Distribution of effects = Target cells are primarily in other tissues and organs and must have appropriate receptors
through the circulatory system
Intercellular communication:
Mechanism = Endocrine communication
Transmission = through the circulatory system
Chemical mediators = _
Distribution of effects = Target cells are primarily in other tissues and organs and must have appropriate receptors
Hormones
Intercellular communication:
Mechanism = Endocrine communication
Transmission = through the circulatory system
Chemical mediators = Hormones
Distribution of effects = _
Target cells are primarily in other tissues and organs and must have appropriate receptors
Intercellular communication:
Mechanism = _
Transmission = across synaptic clefts
Chemical mediators = Neurotransmitters
Distribution of effects = limited to very specific area. Target cells must have appropriate receptors
Synaptic communication
Intercellular communication:
Mechanism = Synaptic communication
Transmission = _
Chemical mediators = Neurotransmitters
Distribution of effects = limited to very specific area. Target cells must have appropriate receptors
across synaptic clefts
Intercellular communication:
Mechanism = Synaptic communication
Transmission = across synaptic clefts
Chemical mediators = _
Distribution of effects = limited to very specific area. Target cells must have appropriate receptors
Neurotransmitters
Intercellular communication:
Mechanism = Synaptic communication
Transmission = across synaptic clefts
Chemical mediators = Neurotransmitters
Distribution of effects = _
limited to very specific area. Target cells must have appropriate receptors
Hormone Communications:
Hormones reach almost all body cells via _
bloodstream
Hormone Communications:
Produce effects only in _ cells that have
_ for the hormone
- “target”
- receptor
Hormone Communications:
Hormone is eventually removed by _
destruction or elimination
Hormone Communications:
Hormone is eventually removed by destruction or elimination
- Freely circulating hormones are _ removed from blood stream
rapidly
Hormone Communications:
Hormone is eventually removed by destruction or elimination
- Hormones bound to _ removed more slowly
transport proteins
Hormone effects on “target” cells
* Target cells have _ for hormone *
receptor
Hormone Communications:
Gene activation leading to synthesis of an
_ or structural _
- enzyme
- protein
Hormone Communications:
- _ of synthesis of an enzyme or structural protein
- Turn an existing enzyme “on” or “off”
Increase or decrease rate
Reflex control of endocrine activity:
_ feedback control mechanism
Negative
Reflex control of endocrine activity:
Negative feedback control mechanism
- in response to changes in composition of
_
interstitial fluids or blood
Reflex control of endocrine activity:
Negative feedback control mechanism
- Location of receptor sensitive to change
may be in the _
gland or in hypothalamus
Reflex control of endocrine activity:
Simple (direct) endocrine reflexes
- _ on gland secreting the hormone
- Example: glucose levels in blood control
insulin release by endocrine cells of
pancreas
Direct effect
Reflex control of endocrine activity:
Complex (indirect) endocrine reflexes
- _ involve hypothalamus, pituitary gland, two or more hormones
Indirect or cascade effects
Hormone communications:
3 Types of hormones
- Amines
- Peptide hormones
- Lipid derivatives
Hormone communications:
Types of hormones
- Norepinephrine, epinephrine, thyroid hormones, etc.
Amines (Amino acid derivatives)
Hormone communications:
Types of hormones
- Insulin, glucagon, growth hormone, etc.
Peptide hormones (chains of amino acids)
Hormone communications:
Types of hormones
- Steroids-structurally related to cholesterol
- Estrogen, testosterone, aldosterone
Lipid derivatives
Amine hormone, Peptide hormone & Protein hormone all have similar _
mechanisms of action
Hormone class _
Components: Amino acids with modified groups
Example: Norepinephrine
Amine hormone
Hormone class _
Components: Short chains of linked amino acids
Example: Oxytocin
Peptide hormone
Hormone class _
Components: long chains of linked amino acids
Example: Human growth hormone
Protein hormone
Hormone class _
Components: Derived from the lipid cholesterol
Example: Testosterone & progesterone
steroid hormones
Mechanisms of hormone action:
Peptide hormones
- Receptors in cell membranes of target cell if
hormone _
cannot cross cell membrane
Mechanisms of hormone action:
Peptide hormones
- Receptors in cell membranes of target cell if
hormone cannot cross cell membrane
- Amines, peptide hormones
- Produce effect via _
G protein-coupled receptors and 2nd messengers
Mechanisms of hormone action:
Peptide hormones
- Produce effect via G protein-coupled receptors and 2nd messengers
- 2nd messenger is _
- Rapidly removed from body
cyclic AMP or calcium
Mechanism of hormone action:
Lipid hormone and Thyroid hormone
- Receptors in the _ for lipid soluble hormones
cytoplasm or nucleus
Mechanism of hormone action:
Lipid hormone and Thyroid hormone
- Thyroid & steroid hormones _ then bind to receptor inside
cross membrane
Mechanism of hormone action:
Lipid hormone and Thyroid hormone
- Produce effect by _ and ATP synthesis
controlling gene expression
Mechanism of hormone action:
Lipid hormone and Thyroid hormone
- Lipid hormones are bound to transport
proteins, so removed from body _
more slowly
Protein hormones (Peptide, Amine):
_, move freely dissolved in plasma
soluble
Protein hormones (Peptide, Amine):
- _ at target cell, binds to G protein-coupled receptor
- activates 2nd messenger
- cAMP
- Ca2+
CANNOT cross cell membrane
Protein hormones (Peptide, Amine):
_ removed from blood stream
rapidly
Lipid hormones & Thyroid (cholesterol, steroid):
- _, must be bound to transport protein in plasma
insoluble
Lipid hormones & Thyroid (cholesterol, steroid):
- _, binds to receptor in cell
CAN cross cell membrane
Lipid hormones & Thyroid (cholesterol, steroid):
Removed _ from bloodstream
slowly
Connected to hypothalamus by
infundibulum
Pituitary Gland (Hypophysis)
Pituitary Gland (Hypophysis):
_ – posterior portion
- developed as outgrowth of CNS
Neurohypophysis
Pituitary Gland (Hypophysis):
_ – anterior portion
- developed as outgrowth of glandular tissue of pharynx
Adenohypophysis
Pituitary Gland (Hypophysis):
Neurohypophysis – posterior portion
- developed as outgrowth of _
CNS
Pituitary Gland (Hypophysis):
Adenohypophysis – anterior portion
- developed as outgrowth of _
glandular tissue of pharynx
Pituitary Gland (Hypophysis):
Releases _ peptide hormones
9
Pituitary Gland (Hypophysis):
Releases 9 peptide hormones
- All 9 bind to membrane receptors and use _ as a second messenger
cAMP or Ca+2
Pituitary Gland (Hypophysis):
_ hormones from Anterior pituitary lobe
7
Pituitary Gland (Hypophysis):
_ hormones from Posterior pituitary lobe
2
Hypothalamus neurons release regulatory
hormones into fenestrated capillaries of
_
hypophyseal portal system
Hypophyseal portal system:
Blood entering the portal system goes to intended _ before returning to general circulation
target cells
Feedback control of hormones of the
adenohypophysis:
Hormone release from adenohypophysis
is controlled by _ secreted by _
- regulatory hormones
- hypothalamus
Thyroid gland produces
C cells (parafollicular cells) and follicle cells
Thyroid gland:
C cells (parafollicular cells)
- Produce _ in response to high calcium ion levels
calcitonin
Thyroid gland:
C cells (parafollicular cells)
_ inhibits osteoclasts and increases Ca2+ excretion by kidney
Calcitonin
Thyroid gland:
Release thyroid hormones
- thyroxine (T4)
- triiodothyronine (T3)
Follicle Cells
Function of thyroid hormones:
Produce strong, immediate, short-lasting
increase in the _
rate of cellular metabolism and use of energy
Function of thyroid hormones:
Cross cell membrane and bind to _ receptors
intracellular
Function of thyroid hormones:
Cross cell membrane and bind to intracellular receptors
- Bind to _ and increase rate of ATP production
mitochondria
Function of thyroid hormones:
Cross cell membrane and bind to intracellular receptors
- Bind to receptors activating genes that
control _ utilization Function of thyroid hormones
energy
Thyroid hormones:
Amino acid with attached _ ions
iodide
Thyroid hormones:
90% of secretions are _ with 4 iodide ions
T4 (thyroxine)
Thyroid hormones:
T4 is converted to _ by enzymes in peripheral tissues
- T3 is the _ of the hormone
- T3 (tri-iodothyronine)
- active form
Thyroid hormones:
Thyroid hormones in bloodstream are attached to transport proteins, creating large reserve supply of _
T4 and T3
Thyroid hormones:
Synthesis and release controlled by _ from
_
- TSH
- adenohypophysis
Function of thyroid hormone:
Essential for normal development of _ during childhood
- Cretinism
skeletal, muscular and nervous systems
Function of thyroid hormone:
Essential for normal _ in adults
- Hypothyroidism
- Hyperthyroidism
- Goiter
metabolic control
Four glands embedded in the posterior
surface of the thyroid gland
Parathyroid glands
Parathyroid glands:
Secretes _ in response to lower than normal
calcium concentration
parathyroid hormone (PTH)
Parathyroid glands:
Secretes parathyroid hormone (PTH) in response to _ than normal _ concentration
- lower
- calcium
Parathyroid glands:
PTH _ concentration
increases
Parathyroid glands:
PTH increases concentration
- Stimulate osteoclasts
- Inhibit osteoblasts
- Decrease Ca2+ excretion by kidneys
- Stimulate formation of _ by
kidneys
calcitriol
Homeostatic regulation of calcium ion
concentration:
_ concentration affects nerve & muscle cell excitability
Ca2+
Homeostatic regulation of calcium ion
concentration:
Ca2+concentration maintained by _ feedback system involving both _ and _
- negative
- PTH & calcitonin
Homeostatic regulation of calcium ion
concentration:
PTH & calcitonin have
effects:
- _ – storage of calcium ions
- Osteoblasts and osteoclasts
Bones
Homeostatic regulation of calcium ion
concentration:
PTH & calcitonin have
effects:
- _ – absorption of calcium
ions
- Calcitriol
Digestive tract
Homeostatic regulation of calcium ion
concentration:
PTH & calcitonin have
effects:
- _ – excretion of calcium ions
Kidneys
Hormones of the adenohypophysis “Tropic Hormones”
- Thyroid stimulating hormone (TSH)
- Adrenocorticotropic hormone (ACTH)
Hormones of the adenohypophysis “Tropic Hormones”:
Thyroid stimulating hormone (TSH) also called _
thyrotropin
Hormones of the adenohypophysis “Tropic Hormones”:
Triggers the release of hormones from thyroid gland
Thyroid stimulating hormone (TSH) (thyrotropin)
Hormones of the adenohypophysis “Tropic Hormones”:
Thyrotropin releasing hormone (TRH) from
hypothalamus promotes the release of _
TSH
Hormones of the adenohypophysis “Tropic Hormones”:
Also called corticotropin
Adrenocorticotropic hormone (ACTH)
Hormones of the adenohypophysis “Tropic Hormones”:
Adrenocorticotropic hormone (ACTH) also called _
corticotropin
Hormones of the adenohypophysis “Tropic Hormones”:
stimulates the release of glucocorticoids from adrenal cortex
Adrenocorticotropic hormone (ACTH) (corticotropin)
Hormones of the adenohypophysis “Tropic Hormones”:
Corticotropin releasing hormone (CRH) from
hypothalamus causes the secretion of _
ACTH
Hormones of the adenohypophysis:
2 Gonadotropins
- Follicle stimulating hormone (FSH)
- Luteinizing hormone (LH)
Hormones of the adenohypophysis:
Gonadotropins
- Stimulates follicle development (egg maturation) & estrogen secretion in ovaries
Follicle stimulating hormone (FSH)
Hormones of the adenohypophysis:
Gonadotropins
- Stimulates sperm production in sustentacular cells of testes
Follicle stimulating hormone (FSH)
Hormones of the adenohypophysis:
Gonadotropins
- Causes ovulation & progestin production in ovaries
Luteinizing hormone (LH)
Hormones of the adenohypophysis:
Gonadotropins
- Causes androgen (testosterone) production in testes
Luteinizing hormone (LH)
Hormones of the adenohypophysis:
Gonadotropin releasing hormone (GmRH) from hypothalamus promotes secretion of _
FSH & LH
Hormones of the adenohypophysis:
- Stimulates the development of mammary glands and milk production
Prolactin (PRL)
Hormones of the adenohypophysis:
Stimulates the development of mammary glands and milk production
- Release stimulated by _ from hypothalamus (inhibited by Inhibiting Hormone)
Prolactin Releasing Hormone
Hormones of the adenohypophysis:
Stimulates melanocytes to produce melanin pigment in skin and other locations
Melanocyte stimulating hormone (MSH)
Hormones of the adenohypophysis:
Stimulates melanocytes to produce melanin pigment in skin and other locations
- In humans, _ MSH is produced by pituitary gland
very little
Growth hormone (GH or somatotropin):
Tropic effect - Cause release of _ from liver
somatomedins
Growth hormone (GH or somatotropin):
Tropic effect - Cause release of somatomedins from liver
- Somatomedins cause increase in amino acid
uptake in skeletal muscle cells, cartilage cells – stimulates _ and cell growth
protein synthesis
Growth hormone (GH or somatotropin):
Direct effect - increase _ in epithelial & connective tissue, enhance break down of lipid & glycogen energy reserves
cell division
Growth hormone (GH or somatotropin):
_ - increase cell division in epithelial & connective tissue, enhance break down of lipid & glycogen energy reserves
Direct effect
Growth hormone (GH or somatotropin):
_ - Cause release of somatomedins from liver
Tropic effect
Growth hormone (GH or somatotropin):
Release controlled by _ and _ from hypothalamus
GH releasing hormone (GH-RH) &
GH inhibiting hormone (GH-IH)
Neurohypophysis (posterior lobe of the pituitary gland):
Contains _ of hypothalamic nerve cells - secrete hormones into blood
axon terminals
Neurohypophysis (posterior lobe of the pituitary gland):
- Decreases the amount of water lost at the
kidneys – decreases urine production
- Elevates blood pressure
Antidiuretic hormone (ADH)
Neurohypophysis (posterior lobe of the pituitary gland):
- Stimulates contractile cells in mammary
glands
- Stimulates smooth muscle cells in uterus
Oxytocin
2 Neurohypophysis (posterior lobe of the pituitary gland) hormones
- Antidiuretic hormone (ADH)
- Oxytocin
Neurohypophysis (posterior lobe of the pituitary gland):
_ hormone —> kidneys
Antidiuretic hormone (ADH)
Neurohypophysis (posterior lobe of the pituitary gland):
_ hormone —> Males: smooth muscle in ductus deferens and prostate gland; Females: uterine smooth muscle and mammary glands
Oxytocin (OXT)
secretes epinephrine and norepinephrine
Adrenal medulla (neuro-endocrine cells)
secretes steroid hormones (corticosteroids)
Adrenal cortex (gland cells)
Adrenal medulla (neuroendocrine cells):
Secretes _ (~75 - 80%)
epinephrine
Adrenal medulla (neuroendocrine cells):
Secretes _ (~20-25%)
norepinephrine
Adrenal medulla (neuroendocrine cells):
Secretes epinephrine & norepinephrine
- Produce increased availability of _
energy resources
Adrenal medulla (neuroendocrine cells):
Produce increased availability of energy resources
- Cause breakdown of glycogen in liver to release glucose for use by _
brain
Adrenal medulla (neuroendocrine cells):
Produce increased availability of energy resources
- Cause breakdown of _ for use by other cells of body
fat to release fatty acids
Adrenal medulla (neuroendocrine cells):
Produce increased rate & force of _ contractions and other _ effects
- cardiac
- sympathetic
Adrenal medulla (neuroendocrine cells) controlled by _ activity
Autonomic Nervous System
Adrenal cortex (secretes corticosteroids):
3 types
- Mineralocorticoids (aldosterone)
- Glucocorticoids
- Androgens
Adrenal cortex (secretes corticosteroids):
- Secreted if Na+ is low, K+ is high, or BP is low
Mineralocorticoids (aldosterone)
Adrenal cortex (secretes corticosteroids):
- Cause retention of Na+ and water, loss of K+
Mineralocorticoids (aldosterone)
Adrenal cortex (secretes corticosteroids):
Mineralocorticoids (aldosterone)
- Cause retention of _, loss of K+
Na+ and water
Adrenal cortex (secretes corticosteroids):
Secreted in response to ACTH release from anterior pituitary
Glucocorticoids
Adrenal cortex (secretes corticosteroids):
Glucocorticoids
- Cause decrease _ and increased rate of glycogen synthesis
- Have anti-inflammatory effects
use of glucose
Adrenal cortex (secretes corticosteroids):
- encourages bone and muscle growth, blood formation
- testosterone
Androgens
Adrenal cortex (secretes corticosteroids):
Androgens
- primary role is in _; testes of adult males produces larger amounts
children & women
Pineal gland secretes _
melatonin
Pineal gland:
Melatonin
- Increased _ exposure causes _ melatonin secretion
- sunlight
- decreased
Pineal gland:
Possible functions include:
– setting circadian rhythms
– anti-oxidant
– inhibiting reproductive function
Melatonin
Pineal gland:
Depression correlated with decreased sunlight exposure and increased melatonin
Seasonal Affective Disorder
99% of pancreas is _ cells
– secrete enzymes into digestive tract
exocrine
Pancreas:
Endocrine cells occur in _
small clusters
Pancreas:
Endocrine cells occur in small clusters
- Islets of Langerhans or pancreatic islets
“islands” on pancreas that are only providing hormones
Pancreas:
Endocrine cells occur in small clusters
- Secrete hormones involved in regulation of
_ level
blood glucose
Pancreas:
Alpha cells secrete _ in response to _
blood glucose levels
- low
- glucagon
Pancreas:
_ cells secrete glucagon in response to low
blood glucose levels
Alpha
Pancreas:
Beta cells secrete _ in response to _ blood glucose levels
- insulin
- high
Pancreas:
_ secrete insulin in response to high blood glucose levels
Beta cells
_ secreted by Beta (β) cells
Insulin
Insulin – secreted by Beta (β) cells:
_ blood glucose levels
lowers
Insulin – secreted by Beta (β) cells:
Increases rate of glucose uptake & utilization
in _ cells
insulin-dependent
Insulin – secreted by Beta (β) cells:
Increases rate of glucose uptake & utilization
in insulin-dependent cells
- Glucose used for energy production and/or
synthesis of glycogen and other energy storage _
macromolecules
Insulin – secreted by Beta (β) cells:
Increased uptake of _ & synthesis of _ in adipose cells
- fatty acids
- triglycerides
Insulin – secreted by Beta (β) cells:
Increased uptake of _ & synthesis of proteins
amino acids
_ secreted by Alpha (α) cells
Glucagon
Glucagon – secreted by Alpha (α) cells:
_ blood glucose levels
raises
Glucagon – secreted by Alpha (α) cells:
Increases the rate of _
glycogen breakdown
Glucagon – secreted by Alpha (α) cells:
Increases the rate of glycogen breakdown
- In liver: glucose _
released into blood
Glucagon – secreted by Alpha (α) cells:
Increases the rate of glycogen breakdown
- In muscle: glucose _ cells
remains in muscle
Glucagon – secreted by Alpha (α) cells:
Increases _ manufacture by _
– Gluconeogenesis from amino acids
- glucose
- liver
Glucagon – secreted by Alpha (α) cells:
Increased release of _ from adipose tissue
fatty acids into blood
Glucagon – secreted by Alpha (α) cells:
Increased release of fatty acids into blood from adipose tissue
- _: most cells start using FA as energy source instead of glucose
Glucose sparing
2 types of diabetes
- diabetes insipidus
- diabetes mellitus
Diabetes:
- Polyuria – excess urine production
- inadequate ADH secretion
Diabetes insipidus
Diabetes:
- _ – excess urine production
Polyuria
Diabetes insipidus:
- Polyuria – excess urine production
- inadequate _
ADH secretion
Diabetes:
- Polyuria – excess urine production
– Glycosuria – glucose in urine
– Hyperglycemia – abnormally high glucose levels in blood
– Breakdown of lipids and proteins as energy
source for cell metabolism
Diabetes mellitus
Diabetes mellitus:
_ – glucose in urine
Glycosuria
Diabetes mellitus:
_ – abnormally high glucose levels in blood
Hyperglycemia
Diabetes mellitus:
Breakdown of _ as energy source for cell metabolism
- Ketone bodies, ketoacidosis
lipids and proteins
Diabetes Mellitus:
Type _ – insulin dependent
– Inadequate insulin production
I
Diabetes Mellitus:
Type _ – non-insulin dependent
– Inadequate insulin response
II
Diabetes Mellitus:
Type I – insulin dependent
– Inadequate _
insulin production
Diabetes Mellitus:
Effects of _
- Diabetic microvascular disorders
- Diabetic cardiovascular changes
high glucose &/or low insulin
Diabetes Mellitus:
Type II – non-insulin dependent
– Inadequate insulin _
response
Adipose Tissue:
feedback control for appetit
Leptin
Adipose Tissue:
reduces insulin sensitivity
Resistin
The Endocrine Tissues of Other Systems:
coordination of digestive activities
Intestine
The Endocrine Tissues of Other Systems:
hormones regulating blood volume, blood pressure, blood calcium level
Kidneys
The Endocrine Tissues of Other Systems:
ovaries & testes secrete hormones involved in reproductive functions
Gonads
A blood test with a high TSH level might indicate _
a problem with the thyroid gland causing low thyroid hormone levels
Gastrointestinal (GI) tract or alimentary canal
- muscular tube
- Extends from oral cavity to anus
Digestive tract
Accessory organs of the digestive tract
Salivary glands, liver, gallbladder, pancreas
Functions of the digestive system:
- eating, drinking
Ingestion
Functions of the digestive system:
- mastication, churning, swallowing, peristalsis
Mechanical processing and propulsion
Functions of the digestive system:
- breakdown of ingested material via acids and
enzymes
Digestion
Functions of the digestive system:
- exocrine secretions into lumen of GI tract
Secretion
Functions of the digestive system:
- movement of nutrients, vitamins, ions, water out of lumen
Absorption
Functions of the digestive system:
- ejection of waste products
Excretion
Histological organization of digestive tract:
- inner-most layer
mucosa
Histological organization of digestive tract: inner layer
- Many exocrine & endocrine gland cells
- Epithelial cells replaced rapidly by stem cells
mucosa
Histological organization of digestive tract: inner layer
- Layer of dense irregular connective tissue
- blood vessels and lymph vessels
submucosa
Histological organization of digestive tract: Inner layer
- Outer longitudinal layer and inner circular layer
– Stomach has third oblique layer, innermost
- Provides mechanical processing and movement of materials along digestive tract
Muscularis layer - smooth muscle
Histological organization of digestive tract: Outer layer
- covers muscularis of oral cavity, pharynx, esophagus & rectum
- connects firmly to adjacent body wall
Adventitia
Histological organization of digestive tract: Outer layer
- covers muscularis of all parts of digestive tract that are free to move
Serosa (Peritoneum)
Histological organization of digestive tract: Outer layer
- Visceral and parietal peritoneum
- _ - extensions of peritoneum - connect digestive tract to body wall and other viscera
Serosa (Peritoneum)
- Mesentery
Contains sensory neurons, interneurons, and motor neurons
Enteric Nervous System (2nd brain)
Enteric Nervous System
- _ plexus
- _ plexus
- Input from parasympathetic and sympathetic ANS
- myenteric
- submucosal
_ factors control movement & gland secretions
Neural, hormonal, & local
Neural, hormonal, & local factors control movement & gland secretions:
Neural
- ANS long reflexes – control _
large areas
Neural, hormonal, & local factors control movement & gland secretions:
Neural
- ANS long reflexes – control large areas
– GI activity _ by parasympathetic
stimulated
Neural, hormonal, & local factors control movement & gland secretions:
Neural
- ANS long reflexes – control large areas
– GI activity _ by sympathetic activity
inhibited
Neural, hormonal, & local factors control movement & gland secretions:
Neural
- Short reflexes – _
- Control within the enteric nervous system
localized responses
Neural, hormonal, & local factors control movement & gland secretions:
- varies by area of GI tract
Hormonal
Neural, hormonal, & local factors control movement & gland secretions:
- varies by area, mainly
Histamine
Local
Movement of digestive materials:
- Churn and fragment a bolus of digestive contents, mixing in intestinal secretions
segmentation
Movement of digestive materials:
- waves that move a
bolus down the length of the tract
peristalsis
3 phases of regulation of gastric activity
- cephalic phase
- gastric phase
- intestinal phase
Regulation of gastric activity:
_ phase prepares stomach to receive ingested material
Cephalic phase
Regulation of gastric activity:
_ phase begins with the arrival of food in the stomach
- Neural, hormonal, and local responses
Gastric phase
Regulation of gastric activity:
_ phase controls the rate of gastric emptying
Intestinal phase
Regulation of gastric activity:
- Prepare stomach for arrival of food
- Initiated by sight, smell, taste, of food
- Produced via parasympathetic stimulation from vagus nerve (CN X)
Cephalic phase
Regulation of gastric activity:
Cephalic phase
- Produced via parasympathetic stimulation from vagus nerve (CN X)
– Excitatory to mucous cells = _
mucus released
Regulation of gastric activity:
Cephalic phase
- Produced via parasympathetic stimulation from vagus nerve (CN X)
– Excitatory to parietal cells = _
H+ & Cl- released
Regulation of gastric activity:
Cephalic phase
- Produced via parasympathetic stimulation from vagus nerve (CN X)
– Excitatory to chief cells = _
pepsinogen released
Regulation of gastric activity:
Cephalic phase
- Produced via parasympathetic stimulation from vagus nerve (CN X)
– Excitatory to G cells = _
gastrin secreted
Regulation of gastric activity:
Mechanical activity producing chyme
- Mixing of food with digestive enzymes & acid
- Maceration of food into small particles
Gastric phase
Regulation of gastric activity:
Gastric phase
- stimulated by _
stretching of stomach wall, by pH increase, by undigested protein
Regulation of gastric activity:
Gastric phase
- stimulated by stretching of stomach wall, by pH increase, by undigested protein
– Excitation of _ gland and _
- gastric
- mucous cells
Regulation of gastric activity:
Gastric phase
- stimulated by stretching of stomach wall, by pH increase, by undigested protein
– Excitation of _
G cells
Regulation of gastric activity:
Gastric phase
- stimulated by stretching of stomach wall, by pH increase, by undigested protein
– Excitation of stomach _
wall muscles
Regulation of gastric activity:
Gastric phase
- food stays in stomach _, mechanical activity increases over time
3-4 hours
Regulation of gastric activity:
Intestinal phase
- Release chyme into small intestine
– _ quantities exit via pyloric
sphincter
small
Regulation of gastric activity:
Intestinal phase
- Slow rate of emptying controlled by feedback from small intestine causing:
– Inhibition of _ gland cells
– Inhibition of _ wall muscle
- gastric
- stomach
Regulation of gastric activity:
Intestinal phase
- _ of stomach caused by:
– stretching of intestinal wall
– pH decrease in intestine
– undigested lipids and carbohydrates
Inhibition
Regulation of gastric activity:
Intestinal phase
- _ is mixed with
– Secretions and buffers
provided by pancreas, liver, gallbladder, and gland cells in intestinal epithelium
Chyme in duodenum
Regulation of gastric activity:
Intestinal phase
- Local _ slowly propel chyme forward
peristaltic movements
Regulation of gastric activity:
Intestinal phase
- As chyme is processed and
moves onward:
– inhibition _
decreases
Regulation of gastric activity:
Intestinal phase
- As chyme is processed and
moves onward:
– increased _ in stomach
releases another quantity of _
- motility
- chyme
Responsible for ~80% of stomach ulcers
- Penetrates mucus coating, releases toxins that damage epithelium
Helicobacter pylori
Helicobacter pylori:
- _ allows gastric “juices” to enter wall of stomach
– Pain, bleeding
– Perforation of wall can occur if untreated, stomach
contents leak into peritoneal cavity
Loss of epithelium
Helicobacter pylori:
- Treat with _ to kill H. pylori bacteria
- Treat with _ to improve healing
- antibiotics
- antacids & dietary restriction
Large portion of stomach and duodenum are bypassed
gastric bypass surgery
Stomach opening can be loosened over time to change the size of passage
- feel full really quickly
- loosen once new lifestyle can be maintained
stomach banding surgery
Absorption of water:
Nearly all water that is _ is absorbed
ingested or secreted into GI tract
Absorption of water:
Nearly all water that is ingested or secreted into GI tract is absorbed
- about _ per day
9,000 ml/day
Absorption of water:
- _ ml ingested
- _ ml from secretions (saliva, gastric, intestinal, liver, pancreas, colon)
- Approximately _ ml left in feces
- 2,000
- 7,000+
- 150
Absorption of water:
Water moves out of _, into body - moves down its
concentration gradient
lumen
Absorption of water:
Water moves out of lumen, into body - moves down its
concentration gradient
- osmosis = diffusion of water
- as solutes are absorbed out of lumen, _, water moves out
osmolarity increases
Nutrients - Digestion & Absorption:
Absorption of nutrients
following breakdown of
macromolecules
- Monomers absorbed on
lumen side of _
epithelial cells
Nutrients - Digestion & Absorption:
Absorption of nutrients
following breakdown of
macromolecules
- Release from _ into interstitial fluids
epithelial cells
Nutrients - Digestion & Absorption:
Absorption of nutrients
following breakdown of
macromolecules
- Diffusion from interstitial
fluids into _ of vascular system or _ of lymphatic system
- capillaries
- lacteal
Carbohydrates - Digestion & Absorption:
Oral cavity, stomach, small intestine
- Salivary and pancreatic _
– Polysaccharides → Disaccharides
amylase enzyme
Carbohydrates - Digestion & Absorption:
Oral cavity, stomach, small intestine
- Brush border enzymes (sucrase, lactase, etc.)
– Disaccharides → _
monosaccharides
Carbohydrates - Digestion & Absorption:
- Absorption of monosaccharides into epithelia by specific _
– facilitated diffusion & co-transport
transport proteins
Carbohydrates - Digestion & Absorption:
Release to _ by specific transport proteins
interstitial fluids
Carbohydrates - Digestion & Absorption:
- Diffuse into _
blood capillaries
Lipids - Digestion, Absorption & Transport:
- Bile salts in duodenum
– emulsify lipid into small droplets for better enzyme access
– complex with monomers to form _
micelles
Lipids - Digestion, Absorption & Transport:
_ diffuse into epithelial cells
Micelles
Lipids - Digestion, Absorption & Transport:
_ formed in epithelia cells
Chylomicrons
Lipids - Digestion, Absorption & Transport:
triglycerides made from monomers & combine with proteins to form
Chylomicrons
Lipids - Digestion, Absorption & Transport:
Chylomicrons released by _ from epithelial cells and enter lacteals
exocytosis
Lipoproteins (soluble complexes of lipids and
proteins):
- largest lipoprotein, mostly triglycerides
chylomicrons
Lipoproteins (soluble complexes of lipids and
proteins):
1. Chylomicrons
- Produced by intestinal epithelial cells from lipids absorbed during _
digestion
Lipoproteins (soluble complexes of lipids and
proteins):
1. Chylomicrons
Lipoprotein _ in capillary walls releases _ and
monoglycerides from chylomicrons
- lipase
- fatty acids
Lipoprotein produced by the liver:
- Transport of triglycerides to peripheral tissues
- Fatty acids released by
lipoprotein lipase
- Very low-density lipoproteins (VLDLs)
Lipoprotein produced by the liver:
- Transport of cholesterol
peripheral tissues
- Enter cells by receptor mediated endocytosis
- Low-density lipoproteins (LDLs)
Lipoprotein produced by the liver:
3. Low-density lipoproteins (LDLs)
- Transport of _ peripheral tissues
cholesterol
Lipoprotein produced by the liver:
2. Very low-density lipoproteins (VLDLs)
- Transport of _ to peripheral tissues
triglycerides
Lipoprotein produced by the liver:
4. High-density lipoproteins (HDLs)
- Transport _ diffusing
out of peripheral cells _
- cholesterol
- back into liver
Lipoprotein produced by the liver:
- Transport cholesterol diffusing out of peripheral cells back into liver
- High-density lipoproteins (HDLs)
Oral (buccal) cavity functions
- Analysis of material before swallowing
- Mastication - mechanical processing by the teeth,
tongue, and palatal surfaces - Lubrication via salivary secretions
- Initial digestion of starch (salivary amylase) and lipids (lingual lipase)
- Prevent entry of pathogens
Oral (buccal) cavity functions:
- _ of material before swallowing
Analysis
Oral (buccal) cavity functions:
- mechanical processing by the teeth, tongue, and palatal surfaces
Mastication
Oral (buccal) cavity functions:
- Lubrication via _
salivary secretions
Oral (buccal) cavity functions:
- Initial digestion of _ (salivary amylase) and _ (lingual lipase)
- starch
- lipids
Oral (buccal) cavity functions:
- Prevent entry of pathogens
- Palatine, Lingual & Pharyngeal _ –
lymphoid organs of immune system Oral (buccal) cavity functions
tonsils
Salivary glands 3 pairs
- Parotid glands
- Sublingual glands
- Submandibular glands
Salivary glands:
1. Parotid glands ( _ of saliva secretion)
~25%
Salivary glands:
2. Sublingual glands ( _ of saliva secretion)
~5%
Salivary glands:
3. Submandibular glands ( _ of saliva secretion)
~70%
Functions of saliva:
- Watery solution (99.4% water) to _
moisten food
Functions of saliva:
- _ (mucins) for lubrication
Glycoproteins
Functions of saliva:
- Buffers to maintain _
neutral pH
Functions of saliva:
- _ & lysozymes to control oral bacteria
Antibodies (IgA)
Functions of saliva:
- Salivary amylase enzymes to initiate digestion of _
complex carbohydrates
Functions of saliva:
- _ to initiate lipid digestion
Lingual lipase
Common passageway for
food, liquids, and air
pharynx
- Connects to trachea and esophagus
- Pharyngeal skeletal muscles assist in swallowing
pharynx
Carries solids and liquids from the pharynx to the stomach
Esophagus
- Skeletal muscle and smooth muscle
- Upper and lower esophageal
Esophagus
4 phases for Swallowing
(deglutition)
- Buccal phase
- Pharyngeal phase
- Bolus enters stomach
- Esophageal phase
Phases for Swallowing
(deglutition):
- voluntary, tongue moves bolus into pharynx
- Soft palate, uvula elevate to close off nasopharynx
- Buccal phase
Phases for Swallowing
(deglutition):
- involuntary control via swallowing center
- Elevate larynx and close epiglottis (Breathing stops momentarily)
- Pharyngeal muscles move bolus downward into esophagus
- pharyngeal phase
Phases for Swallowing
(deglutition):
- involuntary control via swallowing center
- Peristalsis moves bolus downward
- Lower esophageal sphincter opens and food enters stomach
Esophageal phase
Voluntary phases for Swallowing (deglutition)
Buccal phase
Involuntary phases for Swallowing (deglutition)
- pharyngeal phase
- esophageal phase
Anatomy of the stomach
Cardia, Fundus, Body, Pylorus
Anatomy and function of the
stomach:
- _ controls movement of contents of stomach into intestine
Pyloric sphincter
Function of the stomach:
- _ of undigested food
Bulk storage
Function of the stomach:
- Mechanical breakdown of food & mixing with stomach secretions
– _ via longitudinal, circular and oblique muscle layers
– _ (digested food)
- Churning
- chyme
Function of the stomach:
- Disruption of chemical bonds via acids and enzymes = _
digestion
Gland cells of the stomach:
Gastric pits
- Mucous cells produce _ to protect stomach epithelium
alkaline mucus
Gland cells of the stomach:
Gastric pits
- _ to produce new epithelial cells
stem cells
Gland cells of the stomach:
Pyloric glands
- At base of _ in pyloric region
gastric pits
Gland cells of the stomach:
Pyloric glands
- _ (enteroendocrine cells) secrete gastrin
G cells
Gland cells of the stomach:
Pyloric glands
- G cells (enteroendocrine cells)
– stimulates _ cells of gastric glands
parietal & chief
Gland cells of the stomach:
Pyloric glands
- G cells (enteroendocrine cells)
– stimulates gastric muscle _
motility
Gland cells of the stomach:
Gastric glands (body & fundus region)
- Chief cells secrete _
pepsinogen
Gland cells of the stomach:
Gastric glands (body & fundus region)
- Chief cells secrete pepsinogen
– Converted to _
pepsin
Gland cells of the stomach:
Gastric glands (body & fundus region)
- Chief cells secrete pepsinogen
– Converted to pepsin
– Pepsin is the _ of stomach
primary proteolytic (protein
digesting) enzyme
Gland cells of the stomach:
Gastric glands (body & fundus region)
- Parietal cells secrete:
– _ needed for Vitamin B12
absorption in small intestine
intrinsic factor
Gland cells of the stomach:
Gastric glands (body & fundus region)
- Parietal cells secrete:
– Hydrogen ions (H+) and Chloride ions (Cl-) which
produce _
hydrochloric acid (HCl)
Control of Acid Secretion:
_ have receptors for three stimulators of acid secretion, reflecting neural, endocrine and paracrine control
Parietal cells
3 stimulators of acid secretion, reflecting neural, endocrine and paracrine control
- Acetylcholine
- Gastrin
- Histamine
Control of Acid Secretion:
Stimulators of acid secretion, reflecting neural, endocrine and paracrine control
- _ (muscarinic type receptor) - from parasympathetic nerve fibers
Acetylcholine
Control of Acid Secretion:
Stimulators of acid secretion, reflecting neural, endocrine and paracrine control
- _ from G cells of gastric glands
Gastrin
Control of Acid Secretion:
Stimulators of acid secretion, reflecting neural, endocrine and paracrine control
- _ (H2 type receptor) – from mast cells of the mucosa
Histamine
Prilosec, Prevacid,
Protonix, etc. are _ drugs that disable the H+ ion ATPase transport protein
Proton pump inhibitor (PPI)
Tagamet (cimetidine),
Zantac, Pepsid, etc. are
_ antagonists that block
stimulation of parietal
cells
Histamine H2 receptor
Digestion and absorption in
stomach:
Preliminary digestion of _
proteins
Digestion and absorption in
stomach:
Preliminary digestion of proteins
- by pepsin from _ of gastric glands
chief cells
Digestion and absorption in
stomach:
Initial digestion of _
- by salivary amylase until pH gets too low
carbohydrates
Digestion and absorption in
stomach:
Initial digestion of carbohydrates
- by _ until pH gets too low
salivary amylase
Digestion and absorption in
stomach:
Initial digestion of _
- by lingual lipase until pH gets too low
lipids
Digestion and absorption in
stomach:
Initial digestion of lipids
- by _ until pH gets too low
lingual lipase
Digestion and absorption in
stomach:
_ kills most bacteria & living cells, breaks down cell walls, connective tissue
HCl
Digestion and absorption in
stomach:
Minimal absorption of _
- Some lipid-soluble drugs are absorbed
nutrients
Digestion and absorption in
stomach:
Minimal absorption of nutrients
- Some _ drugs are absorbed
lipid-soluble
stomach gurgling = _ reflex
vs.
Salivation while eating = _ reflex
- long reflex
- short reflex
The inner-most lining of the digestive tract is called _ layer, and is made up of _ tissue
- mucosal
- epithelial
Which of the following is likely NOT controlled by a short reflex?
- Buffering of acidic components of the stomach (chyme) upon arrival in the duodenum
- your stomach contracting, releasing acid and enzymes if filled with food
- your mouth continually produces saliva while chewing food
- getting the urge to defecate directly after consuming a meal
getting the urge to defecate directly after consuming a meal
Proteins - Digestion & Absorption:
Stomach, small intestine
- Pepsin, trypsin, chymotrypsin, brush border enzymes
– proteins → polypeptides → _
amino acids
Proteins - Digestion & Absorption:
Stomach, small intestine
- _ destroys tertiary and quaternary structure
low pH
Proteins - Digestion & Absorption:
Diffuse into _
blood capillaries
Lipids - Digestion, Absorption & Transport:
Oral cavity, stomach, small intestine
- Lingual and _
pancreatic lipase
Proteins - Digestion & Absorption:
Absorption of amino acids into epithelia by _
AA-specific transport proteins
Proteins - Digestion & Absorption:
Release to _ by AA-specific transport proteins
interstitial fluids
Small intestine:
Muscular tube _ feet long
~20
Three subdivisions of small intestine
- Duodenum
- Jejunum
- Ileum
Three subdivisions of small intestine:
- _ – first 10 inches
Duodenum
Three subdivisions of small intestine:
- _ ~8 feet long
Jejunum
Three subdivisions of small intestine:
- _ ~12 feet long
Ileum
Connection between stomach and small intestine
Pyloric sphincter
Connection between small and large intestine
Ileocecal sphincter
Pancreatic exocrine
secretions:
Released into pancreatic duct that connects to _
duodenum
Pancreatic exocrine
secretions:
Alkaline buffers to _ of
chyme
raise pH
Pancreatic exocrine
secretions:
Digestive enzymes to
breakdown _
macromolecules
Pancreatic digestive enzymes (secreted as inactive enzymes, activated in intestine)
- pancreatic amylase
- lipases
- nucleases
- proteolytic enzymes (protease, peptidases)
Pancreatic digestive enzymes:
Pancreatic amylase (starch –> _)
disaccharides
Pancreatic digestive enzymes:
Lipases (lipids –> _)
fatty acids
Pancreatic digestive enzymes:
Nucleases (nucleic acids –> _)
nucleotides
Pancreatic digestive enzymes:
Proteolytic enzymes (proteins –> polypeptides –> _)
amino acids [dipeptides]
Pancreatic digestive enzymes:
Proteolytic enzymes
- Trypsin
- Chymotrypsin
- carboxypeptidase
- proteases
- peptidases
Liver functions:
1. _
- All blood leaving digestive tract flows into liver
- Liver removes and stores excess nutrients
metabolic regulation
Liver functions:
1. metabolic regulation
- Liver removes and stores excess nutrients
- Corrects nutrient deficiencies by _
mobilizing stored reserves or performing synthetic activities
Liver functions:
2. _
- Liver cells extract nutrients & toxins from blood
- Liver produces plasma proteins
Hematological regulation
Liver functions:
2. Hematological regulation
- Liver cells _ from blood
extract nutrients & toxins
Liver functions:
3. _
Bile production
Bile from liver & gallbladder:
- _ necessary for emulsification of lipids
- Synthesized in liver from cholesterol
Bile salts
Bile from liver & gallbladder:
- Bile salts
– Necessary for _
– Synthesized in liver from cholesterol
emulsification of lipids
Bile from liver & gallbladder:
Water & ions
- Dilute & buffer acids in _
chyme
Bile from liver & gallbladder:
_
- Waste pigment formed from heme of red blood cells phagocytized and recycled by liver
Bilirubin
Bile from liver & gallbladder:
Bilirubin
- Waste pigment formed from _ cells phagocytized and recycled by liver
heme of red blood
Gallbladder – muscular,
expandable sack
- Stores, modifies and
concentrate _
bile
Gallbladder and liver share _
which connects to duodenum
- Connects at same
location as _
- common bile duct
- pancreatic duct
- Controls release of both
pancreatic secretions and
bile
Hepatopancreatic sphincter
4 Hormones secreted by duodenum
- cholecystokinin (CCK)*
- Secretin*
- Gastric inhibitory peptide (GIP)
- Vasoactive intestinal peptide (VIP)
Hormones secreted by duodenum:
Released in response to undigested food
Cholecystokinin (CCK)
Hormones secreted by duodenum:
- Stimulate secretion of pancreatic enzymes
Cholecystokinin (CCK)
Hormones secreted by duodenum:
Cholecystokinin (CCK)
- Inhibit _ & motility
stomach secretions
Hormones secreted by duodenum:
- Stimulate contraction of gallbladder
Cholecystokinin (CCK)
Hormones secreted by duodenum:
- Stimulate relaxation of hepatopancreatic sphincter
Cholecystokinin (CCK)
Hormones secreted by duodenum:
- Released in response to acid chyme
Secretin
Hormones secreted by duodenum:
Secretin
Hormones secreted by duodenum:
Secretin
- Inhibit _ & motility
stomach secretions
Hormones secreted by duodenum:
Stimulate pancreas to release buffers
Secretin
Hormones secreted by duodenum:
Stimulate liver to increase bile secretion
Secretin
Chemical digestion in small intestine - jejunum:
Exocrine secretions of intestinal glands
- Brush border enzymes for disaccharides
- Maltase
- Sucrase
- Lactase
Chemical digestion in small intestine - jejunum:
Exocrine secretions of intestinal glands
- Brush border enzymes for _
– Maltase
– Sucrase
– Lactase
disaccharides
Chemical digestion in small intestine - jejunum:
Exocrine secretions of intestinal glands
- Brush border enzymes for _
– peptidases
small peptides
Chemical digestion in small intestine - jejunum:
Exocrine secretions of intestinal glands
- Brush border enzymes for small peptides
peptidases
Chemical digestion in small intestine - jejunum:
Exocrine secretions of intestinal glands
- Brush border enzymes for _
– Nucleases
nucleic acids
Chemical digestion in small intestine - jejunum:
Exocrine secretions of intestinal glands
- Brush border enzymes for nucleic acids
Nucleases
Chemical digestion in small intestine - jejunum:
Exocrine secretions of intestinal glands
- _ to neutralize stomach acid
Buffers
Structure of the large
intestine:
Muscular tube _ feet long, 3 inches in diameter
~ five
Structure of the large
intestine:
- _ and appendix
- _ – ascending, transverse, descending, sigmoid regions
- _
– Anal canal
- Cecum
- Colon
- Rectum
Histology of the large
intestine:
- _ surface,
- Deep intestinal glands
– Many secreting cells
– Stem cells
Smooth inner
Histology of the large
intestine:
Longitudinal muscles of
muscularis layer reduced to _ bands of muscle, the Taenia coli
3 longitudinal
Functions of the large intestine:
1. Digestion - Bacterial activity
- _ produced by the large intestine
No digestive enzymes
Functions of the large intestine:
1. Digestion - Bacterial activity
- Bacteria living in large intestine breakdown various
organic molecules
– Convert _ to urobilinogens and stercobilinogens
bilirubin
Functions of the large intestine:
1. Digestion - Bacterial activity
- Bacteria living in large intestine breakdown various
organic molecules
– Digest _ to methane ga
carbohydrates
Functions of the large intestine:
1. Digestion - Bacterial activity
- Bacteria manufacture Vitamin K, biotin, and _
vitamin B5
Functions of the large intestine:
1. Digestion - Bacterial activity
- Bacteria manufacture Vitamin K, biotin, and vitamin B5
– Vitamin needed by liver to manufacture _
clotting proteins
Functions of the large intestine:
2. Absorption of _
- Movement from cecum to transverse colon takes hours
water
Functions of the large intestine:
2. Absorption
- _ – K, biotin, and B5 synthesized by bacteria of
large intestine
Vitamins
Functions of the large intestine:
2. Absorption
- Bile salts
- Organic _
– Urobilinogens (to be excreted in urine)
– Ammonia
wastes and toxins
Functions of the large intestine:
- Absorption of water and segmentation movements
in ascending colon compact material into feces
- Formation and expulsion of feces (stool)
Functions of the large intestine:
3. Formation and expulsion of feces (stool)
- _ triggered by stomach distension produces mass movements of feces through colon into rectum
Peristalsis
Defecation Reflex:
- Triggered by _ of rectal walls
distention
Defecation Reflex:
Triggered by distention
of rectal walls
- Relaxation of internal anal sphincter _ controlled by ANS
unconsciously
Defecation Reflex:
Triggered by distention
of rectal walls
- Somatic _ of relaxation of external anal sphincter
conscious control
Control of energy metabolism:
_ breaks down small carbon compounds to make ATP
Mitochondria
Control of energy metabolism:
Mitochondria breaks down small carbon compounds to
make ATP
- Which organic molecules are used depends on _ and availability of _
- hormones
- nutrients
Control of energy metabolism:
Absorptive period - _
insulin is secreted
Control of energy metabolism:
_ - insulin is secreted
- most cells use glucose for energy
Absorptive period
Control of energy metabolism:
Postabsorptive period
- _, glucocorticoids, epinephrine are secreted
- many cells use fatty acids and amino acids for energy
Glucagon
Control of energy metabolism:
_ period
- Glucagon, glucocorticoids, epinephrine are secreted
Postabsorptive
Absorptive Period:
_ enter the blood as intestinal absorption proceeds and insulin is secreted by beta cells of pancreas
Nutrients
Absorptive Period:
Insulin-dependent cells take up _
- Liver regulates glucose content of blood by absorbing excess glucose
glucose
Absorptive Period:
Liver regulates glucose content of blood by absorbing excess glucose
- Uses some for energy
- Stores glucose as glycogen
- Converts excess glucose to _
triglycerides
Absorptive Period:
Insulin-dependent cells take up _
- Muscle cells store glucose as _
- Other tissues absorb glucose to use for energy
glycogen
Absorptive Period:
Neural tissue is_ and cells take up glucose for energy
insulin-independent
Absorptive Period:
triglycerides degraded to fatty acids and monoglycerides by capillary lipases
Chylomicron
Absorptive Period:
_ are absorbed by most cells for protein synthesis, stimulated by insulin, growth hormone, androgen, and estrogen
Amino acids
Postabsorptive period:
From the end of the
absorptive state to the next
meal, body relies on _ for energy production in cells
reserves
Postabsorptive period:
Insulin secretion _
stops
Postabsorptive period:
All are secreted to control _
- Glucagon (alpha cells of
pancreas),
- glucocorticoids
(adrenal cortex),
- epinephrine
(adrenal medulla)
cellular metabolism
Postabsorptive period:
Neural tissue requires glucose for energy
- Liver cells break down glycogen and synthesize glucose (gluconeogenesis), _ into blood
releasing glucose
Postabsorptive period:
All other tissues switch to _ for energy production
- No insulin so can not take in glucose
- Muscle cells use fatty acids while at rest and use glycogen reserves when active
fatty acids
Postabsorptive period:
Tissues can make use of _ breakdown products for energy production if _ are not available
- amino acids
- fatty acids
Postabsorptive period:
Tissues can make use of amino acid breakdown
- Amino acids are de-aminated by the _ to produce ketone acids that can be used in mitochondria for ATP synthesis by most cell
liver
Postabsorptive period:
Tissues can make use of amino acid breakdown
- Liver can use amino acids for gluconeogenesis to supply glucose to _
neural tissue
