Module 9: Homeostasis of Organ Systems Flashcards
Define: Homeostasis
the ability to maintain stable internal conditions despite changes in internal or external environment
Define Steady State and Set Points
Steady State: a small range of internal conditions balanced within the body as a whole
setpoints: ideal internal conditions that are necessary to keep the body healthy
i. e. body temp 37C, blood pH 7.4
General Pathway of Homeostatic Control
- Stimulator
- Sensor
- Control Center
- Effector (target)
- Response
- Negative Feedback: counteracts
- Positive Feedback: amplifies
Endocrine System: Major Structures, Organs, and Functions
- Structures and major organs
- hypothalamus
- anterior and posterior pituitary
- thyroid gland
- parathyroid glands
- adrenal medulla and adrenal cortex
- pancreas
- gonads
- Functions:
- hormonal regulation of growth, metabolism, reproduction, organ system regulation and changes, homeostasis (on a long time scale)
Define: hormone
chemical released into the blood to regulate distant target cells
Define: Endocrinology
The study of hormones and endocrine glands
- Pineal Gland
- Hypothalamus
- Pituiatry Gland
- Thyroid Gland
- Parathyroid Gland
- Thymus
- Adrenal Gland
- Pancreas
- Gonads
- Ovary
- Testes
General Hormone Pathway
Stimulus: Variable(s) that trigger a change in the pathway
Sensor: detects change in variable
Control Center: endocrine gland(s) produce and release hormones
Effector (target): organ(s) or systems that change in response to hormone
Response: Change in variables
Organization of the Peripheral Nervous System
(nerves and receptors outside of the CNS)
- Afferent Division (into the brain/spinal cord)
- somatic sensory receptors/neurons
- visceral receptors/neurons
- special sensory receptors/neurons
- Efferent Divison (out of brain/spinal cord)
- somatic motor neurons/effectors
- autonomic neurons/effectors
- sympathetic
- parasympathetic
Afferent Division
(into the brain/spinal cord)
- somatic sensory receptors/neurons
- visceral receptors/neurons
- special sensory receptors/neurons
Efferent Divison
(out of brain/spinal cord)
- somatic motor neurons/effectors
- autonomic neurons/effectors
- sympathetic
- parasympathetic
Definition and Function: Autonomic Nervous System
- part of the efferent nervous sytem which controls responses of organs and glands
- sympathetic
- parasympathetic
- Function:
- involuntary regulation of homeostasis
- controls responses in cardiac muscle, smooth muscle, endocrine glands, adipose tissue
Sympathetic Nervous System Functions
Part of autonomic nervous system
- INCREASE BLOOD FLOW TO MUSCLES
- increase HR
- increase force of heart contraction
- increase BP
- OPEN AIRWAYS
- increase oxygen
- INCREASE DISTANCE VISION
- dilate pupils
- INCREASED METABOLIC PREPARATION
- increased release of blood sugar and fat
- increased sweat to anticipate excess heat production
Sympathetic Nervous System Targets
- sweat glands: increased secretion
- arrector pili muscle: goosebumps
- cardiovascular system:
- increased blood flow to brain, heart, lungs, muscles, skin
- decreased blood flow to urinary, digestive system
- increased heart rate, heart contraction, blood pressure
- respiratory system: increased airflow
- digestive system: decreased activity and secretions, breakdown nutrient stores
- skeletal muscle: increased contraction force, increased acetylcholine release
- adipose tissue: fat breakdown
- urinary system: decreased urine output due to decreased GFR
- Reproductive System: increased secretion, male ejaculation
SNS and the Adrenal Medulla
- timing and intensity of the SNS response is enhance dby the Adrenal Medulla
- leads to longer lasting effect
- SNS pre-ganglionic neurons target the adrenal medulla
- the adrenal medulla releases catecholamines: epinephrine and norepinephrine (and some dopamine) into the blood stream
- Epi and NorEpi effects enhances at SNS targets!!
Parasympathetic Nervous System Functions
- CONSERVE ENERGY
- decreased HR
- decreased force of contraction of heart
- constrict airways
- INCREASED DIGESTION
- increased mucus, saliva and digestive secretions
- increased digestive motility and relax sphincters
- ADJUST FOR NEAR VISION
- constrict the pupils
- PREPARE FOR SEXUAL ACTIVITY
- increased blood flow to erectile tissues
- increased apocrine (stinky) sweat glands (armpits and genitals)
PSNS Targets
PSNS =parasympathetic nervous system
- l_acrimal glands_: increased tear production
-
cardiovascular system: decreased HR,
- decreased contraction
- decreased BP
- Respiraotory system: decreased airflow
- Salivary Glands: increased secretion
-
Digestive System: increased activity, motility
- increased secretion
- increased nutrient storage
-
Reproductive System: increased secretion
- erection
Chemical Signaling in the SNS
- pre-ganglionic neurotransmitter: acetylcholine
- post-ganglionic neurotransmitter: norepinephrine aka “noradrenaline”
- this is why this is called adrenergic signaling
Chemical Signaling of the PSNS
Parasympathetic Nervous System
- pre-ganglionic neurotransmitter: acetylcholine
- post-ganglionic neurotransmitter: acetylcholine
- this is why this called cholinergic signaling
Cholinergic Receptors
Parasympathetic Nervous System
- cholinergic receptors are specific to acetylcholine
-
Nicotinic Receptors (nAChR’s):
- skeletal muscle
- 5 subunits in various combinations
- receptor ion channels
-
Muscarinic Receptors:
- form G-protein coupled receptor complexes
- 5 types: M1-M5
-
Nicotinic Receptors (nAChR’s):
Adrenergic Receptors
Sympathetic Nervous System
- adrenergic receptors are specific to norepinephrine and epinephrine
- 5 types: alpha1, alpha 2, beta 1, beta 2, beta 3
