Bio Exam 3

Immune System

What is the immune system?

The body’s defense system against small organisms that try to parasite you

How does the immune system work?

Innate Immunity + Adaptive Immunity

Why does the immune response work?

Immunological Memory + Vaccines

Why does the immune response not work?

Allergies, autoimmunity, immunodeficiency (sometimes body reacts to much)

Pathogens

Bacteria, Fungi, Viruses

Innate Immunity

• Barrier Defenses

• Internal Defenses

• All animals

• Rapid response

Adaptive Immunity

• Humoral response

• Cell-mediated response

• Vertebrates only

• Slower but more powerful response

If infection spreads which immunity is the 2nd defense?

Adaptive (acquired) immunity

Examples of barrier defenses

• Skin, tears, ear wax

• Mucous membranes

• Secretions

Examples of internal defenses

• Phagocytic cells

• Natural killer cells

• Antimicrobial proteins

• Inflammatory response

Humoral response

• B cells + antibodies

• Antibodies defend against infection in body fluids

Cell - mediated response

• T cells

• Cytotoxic cells defend against infection in body cells

Inflammatory response

Local response - when skin gets red around splinter

Mast cells release…

• histamines

• triggers blood vessel dilation

• sends out distress signals

Macrophages release…

• cytokines

• signals molecules that recruit more white blood cells

Leukocytes

General term for white blood cells

Which 2 recruit white blood cells?

Mast cells and Macrophages

Phagocytosis

Cells that eat cells/bacteria

Phagocytic cells include…

macrophages localizes in certain body tissues and neutrophils that circulate in the blood stream

Antimicrobial peptides

proteins that recognizance and target pathogens

Inflammatory response ends in the accumulation of?

• Pus

• Evidence of warzone

Pus

Fluid rich in white blood cells, dead pathogens, and cell debris

Lymphatic system

Series of lymphatic vessels that meet at lymph nodes

Lymphatic vessels

• Screens for intruders

• Funnels any pathogens to lymph nodes

Lymph Nodes

• Identify pathogen

• Remove harmful substances like bacteria and viruses

• Store white blood cells to fight infection

• Swell when fighting illness

  • Ex: When testing for strep, doctors check neck lymph nodes to see if they are swollen

Adaptive immunity relies on 2 types of lymphocytes

• B-Cells

• T-Cells

Lymphocytes

• Specific kind of white blood cells

• B and T cells

Antigen receptors

• On surface

• Each lymphocyte has 1 type of antigen receptor

• B Cells have 2

• T Cells have 1

Antigen

Any substance on or secreted by a pathogen that can give an immune response

• B Cells have antigen receptors

Clonal Selection

• B-cell matches foreign antigen, that specific cell activates, divides rapidly (proliferates), and creates many identical copies (clones) of itself to fight the specific pathogen

• Ensures that only B cells capable of binding to a pathogen are expanded

Effector Cells

• Plasma B Cells

• Produce Antibodies

• Fights active infections

Memory B-cells

• long-term

• protection against future repeat exposures to the same pathogen

Neutralization

• Prevents infection

• Naturalize and kills pathogen

Opsonization

• Tags foreign bodies for phagocytosis

• Can flag pathogens for death

T-cells

• Look for infected cells

• Recognize antigen fragments presented by host cells

Host proteins are called…

• MHCs

• Present antigen fragments on a cell surface for recognition

MHC

Major histocompatibility complexes

Helper T-cells

• can bind the antigen fragment proliferate (clonal selection)

• promote proliferation of B-cells

• signal cytotoxic T-cells to kill infected host cells

• memory T - cells

4 reasons why adaptive immunity is powerful

• Diversity of antigen receptors

• B+T cells proliferate (clone) after activation

• Self- tolerance

  • Not binding random cells

• Immunological memory

  • Remembering past infections to attack in future

Autoimmunity

Body looses self tolerance and attacks ones self

Self-reactive lymphocytes undergo…

apoptosis

Gene rearrangement

Cutting out parts of a template to give to a unique antigen receptor

Vaccine

Part of nonliving pathogen so body can remember and identify strains allowing for immediate help

Type of diseases that have vaccines

• Small Pox + Chicken Pox

• Influenza

• Measles

• Hepatitis

• Covid

4 times when the immune response doesn’t work

• Immune Rejection

• Exaggerated response

• Self-directed response

• Diminished response

Immune Rejection

• Blood transfusion

• Organ transplants

• Need to be molecularly compatible

Exaggerated response

Allergies - immune system exaggerates and thinks it’s dangerous when it is not

Self-directed response

• When body looses self tolerance and attacks ones self

• Rheumatoid arthritis

• Lupus

• Multiple sclerosis

Diminished response

• Stress, age, lack of sleep

• Antigenic variation

  • Specific to antigen so if flu mutated then you would need a different/new antigen - ie. why we need new flu shots every year

• Viral latency

  • Viruses cab lay dormant for years and you could be asymptomatic

Endocrine System

What is the endocrine system?

System of organs that coordinate hormones that influence functions and behaviors

How does the endocrine system work?

• Endocrine gland secret hormones

  • Hypothalamus, pituitary, adrenal, thyroid, gonads

• Hormones travel through circulatory system to target cells

• Hormone receptors trigger cellular response

Why does the endocrine system work?

Feedback mechanism

Coordination of biological systems requires…

cell communication

Animals have?

Both Nervous system and Endocrine system

Plants have?

Only Endocrine systems (we and plants have chemical communication)

Question:

Testosterone is an example of a chemical signal that affects

the very cells that synthesize it, the neighboring cells in the

testes, along with distant cells outside the gonads. Thus,

testosterone is an example of?

A) an autocrine signal

B) a paracrine signal

C) an endocrine signal

D) an autocrine signal, a paracrine signal, and an endocrine

signal

D) an autocrine signal, a paracrine signal, and an endocrine

signal

Endocrine signaling

Long distance form of transmitting

Endocrine glands

• Released from majority of body

• Glands main goal is to release hormones

Major endocrine glands

• Hypothalamus

• Pineal gland

• Pituitary gland

• Thyroid gland

• Parathyroid glands

• Adrenal glands

• Pancreas

• Ovaries and Testes

Organs containing endocrine cells

• Thymus

• Heart

• Liver

• Stomach

• Kidneys

• Small Intestine

• Pancreas

• Ovaries and Testes

Water-soluble hormones (hydrophilic)

• Polypeptides

  • Insulin

• Amines

  • Epinephrine (adrenaline)

Lipid-soluble hormones (hydrophobic)

• Steroids

  • Cortisol (stress hormones)

• Amines

  • Thyroxine

A single hormone can have multiple effects

• different receptors for the same hormone can trigger different transduction pathways

• same receptors for the same hormone can have different signal transduction pathways

Negative feedback

Inhibits a response by reducing the initial stimulus

• epinephrine, cortisol

Positive feedback

reinforces a stimulus to produce an even greater response

• oxytocin, estradiol

Question:

An example of antagonistic hormones controlling

homeostasis via negative feedback is?

A) oxytocin and prolactin in milk production

B) insulin and glucagon in glucose metabolism

C) thermostat controlling the temperature in a room

D) pheromonal attraction

B) insulin and glucagon in glucose metabolism

HPE (GTA) system

• Hypothalamus receives information from nervous system and secretes hormones

• Pituitary glands receives released hormones from the hypothalamus and secretes tropic hormones

• Tropic hormones trigger hormone secretion in endocrine glands (gonads, thyroid, adrenal glands)

Posterior Pituitary

ADH

• regulates water balance and blood pressure

• Target → Kidney tubules

Oxytocin

• affects social bonding behaviors, childbirth and milk secretion

• Target → Mammary glands, uterine muscles

Antierior Pituitary

Tropic effects

FSH/LH - release s3x hormones from gonads

• Target → Testes and Ovaries

TSH - releases thyroid hormones

• Target → Thyroid

ACTH - releases stress hormones

• Target → Adrenal cortex

Non-tropic effects

Prolactin - promotes milk production

• Target → Mammary Glands

MSH - promotes melanin
Target → Melanocytes

Tropic and non-tropic effects

GH - directs bone growth

• Target → Liver, bones, other tissues

Gonadal Hormones - Gonads

• Ovaries and testes

• Secret steroid sex hormones in response to anterior pituitary hormones FSH and LH

  • Androgens (testosterone) - male skewed

  • Estrogens (estradiol) - female skewed

  • Progestins (progesterone) - female skewed

Thyroid hormones - thyroid

• general metabolism and physiology

• Secretes two hormones in response to TSH

  • Triiodothyronine (T3)

  • Thyroxine (T4)

Adrenal hormones - adrenal gland

• stress response

• secretes a variety of hormones in response to stress (ACTH release)

  • steroid hormones (cortisol, aldosterone)

  • amines (epinephrine/adrenaline)

    • mediate fight or flight

Animal Reproduction

What is reproduction?

Generation of new individuals from existing individuals

How does reproduction occur in animals?

• Asexual versus sexual reproduction

• Internal versus external fertilization

• Specialized reproductive organs

  • Testes → sperm

  • Ovaries → egg

  • Accessory glands and ducts

Why does the reproductive system work?

Endocrine regulation (H-P-G axis)

Question:

Suppose you wanted to start an animal-breeding business.

For most of the following animals, you could start out with

just a single animal. Which of the animals below would

require that you start with at least two individuals?

A) Whiptail lizards

B) Hammerhead shark

C) Bullfrog

D) Komodo dragons

C) Bullfrog

Sexual Reproduction

Creation of zygote by fusion of male gamete (sperm) and female gamete (egg)

Asexual reproduction

Creation of offspring without the fusion of egg and sperm

Fission and Fragmentation

• Asexual

• Separation of a parent into two or more individuals

  • Worm like creature tearing in half and growing to be an individual

Budding

• Asexual

• New individuals arise from outgrowths of existing ones

  • moss piece taking off and moved somewhere else and begins to grow again

Parthenogenesis

• Asexual

• Development of new individual from an unfertilized egg

Eusocial Insects

• Colony - Queens do the reproduction

• Bees, wasps, ants, termites

Hermaphroditism

Sequential + Simultaneous

Sequential

• Can change sex throughout life, all typically start as male and produce sperm then switch to female

• Clownfish, blue head wrasse

Simultaneous

• Female and male at same times - make sperms and egg

• Earthworms, sea slugs, hamlet fish

Parthenogenesis with ‘mating’

• all females

• take turns acting in male+female s3x roles

Reproductive cycles

• related to changing seasons

• controlled by hormones and environmental cues

Internal fertilization

Eggs are fertilized sperm in the female reproductive tract

• requires behavioral interactions (courtship) and compatible copulatory organs

External fertilization

Eggs are fertilized by sperm in the external environment

• Requires aqueous environment and precise timing

• Sperm and egg goes into water and fertilizes

  • Bullfrogs

Gonads

Organs that produce gametes

Non-mammalian vertebrates have…

• cloaca

• fish, amphibians, reptiles, birds

Cloaca

Common opening between the external environment and the digestive, excretory, reproductive systems

Female reproductive anatomy

Egg cell production, fertilization, embryo development

• Egg cells produced in → ovaries

• Fertilization occurs in → oviducts/fallopian tubes

• Embryo develops in → uterus

Question:

In male mammals, excretory and reproductive systems

share?

A) the testes

B) the urethra

C) the seminal vesicle

D) the vas deferens

B) the urethra

Male reproductive anatomy

Sperm (gamete) and Semen (sperm+fluid) production

• Sperm are produced in → seminiferous tubules in testes

• Sperm are propelled via → the muscle vas deferens to form semen during ejaculation

Gametogenesis

Production of gametes